Psychology & Neurosciencehttps://hdl.handle.net/10023/1302024-03-26T22:02:18Z2024-03-26T22:02:18ZDopaminergic modulation of locomotor networks in larval Drosophila melanogasterMacLeod, Jameshttps://hdl.handle.net/10023/292012024-02-10T03:05:56Z2022-06-17T00:00:00Z2022-06-17T00:00:00ZMacLeod, JamesThe representational systems for object and agent in new world monkeysZhang, Dahttps://hdl.handle.net/10023/291442024-02-03T03:01:12Z2021-11-30T00:00:00ZRepresenting the environment in its most basic components, namely objects and agents, is a fundamental feature of human cognition which we may share to different extents with nonhuman animals. This thesis explored some manifestations of these abilities in two new world monkey species, squirrel monkeys and capuchin monkeys.
We first investigated squirrel monkeys’ ability of individuating object by spatiotemporal and property/kind information with a “magic box” paradigm using both manual search and looking time measures (chapter 2). The squirrel monkeys failed both tasks with both measures, whereas capuchin monkeys showed individuating competence with exactly the same tasks and apparatus in a previous study.
Chapter 3 tested and explored the possibility that squirrel monkeys failed the “magic box” tasks that capuchin monkeys passed because they acted so fast that they didn’t form or use this type of object representations to guide their actions. In fact, in a touchscreen-based object tracking/catching game (Whack-a-cricket task), the squirrel monkeys were slower to “catch”
a moving “cricket” compared to capuchin monkeys.
In chapter 4, we tested squirrel monkeys with another individuation task that included two separate barriers instead of a single box. The squirrel monkeys preferred to search the last- visited-location first when either spatiotemporal or property/kind information suggested that only one object was present. This preference disappeared when either information indicated that there were two objects, one behind each barrier. We conclude that squirrel monkeys are therefore able to individuate objects using both kinds of information when tested with an appropriate task.
In the last chapter, we investigated whether capuchin monkeys can locate a causal agent based on an event that he initiated from a hidden location. Capuchin monkeys located the hidden agent when they saw an object pushed, raked, rolled, or thrown across a table seemingly by the experimenter behind one of two screens (agentive trials), but not when they saw an object roll down a ramp or fall off a block after a shake of the table (arbitrary control trials) that contained no information about the agent’ location. This result suggests capuchin monkeys can use motion events to infer the location of a causal agent, an ability also demonstrated by human infants.
Taken together, our studies show that squirrel monkeys and capuchin monkeys have some core abilities to represent some of the fundamental properties of objects and agents, comparable to those demonstrated by human infants, which supports the core knowledge view that such representational systems may have a long evolutionary history and exist widely in primates.
2021-11-30T00:00:00ZZhang, DaRepresenting the environment in its most basic components, namely objects and agents, is a fundamental feature of human cognition which we may share to different extents with nonhuman animals. This thesis explored some manifestations of these abilities in two new world monkey species, squirrel monkeys and capuchin monkeys.
We first investigated squirrel monkeys’ ability of individuating object by spatiotemporal and property/kind information with a “magic box” paradigm using both manual search and looking time measures (chapter 2). The squirrel monkeys failed both tasks with both measures, whereas capuchin monkeys showed individuating competence with exactly the same tasks and apparatus in a previous study.
Chapter 3 tested and explored the possibility that squirrel monkeys failed the “magic box” tasks that capuchin monkeys passed because they acted so fast that they didn’t form or use this type of object representations to guide their actions. In fact, in a touchscreen-based object tracking/catching game (Whack-a-cricket task), the squirrel monkeys were slower to “catch”
a moving “cricket” compared to capuchin monkeys.
In chapter 4, we tested squirrel monkeys with another individuation task that included two separate barriers instead of a single box. The squirrel monkeys preferred to search the last- visited-location first when either spatiotemporal or property/kind information suggested that only one object was present. This preference disappeared when either information indicated that there were two objects, one behind each barrier. We conclude that squirrel monkeys are therefore able to individuate objects using both kinds of information when tested with an appropriate task.
In the last chapter, we investigated whether capuchin monkeys can locate a causal agent based on an event that he initiated from a hidden location. Capuchin monkeys located the hidden agent when they saw an object pushed, raked, rolled, or thrown across a table seemingly by the experimenter behind one of two screens (agentive trials), but not when they saw an object roll down a ramp or fall off a block after a shake of the table (arbitrary control trials) that contained no information about the agent’ location. This result suggests capuchin monkeys can use motion events to infer the location of a causal agent, an ability also demonstrated by human infants.
Taken together, our studies show that squirrel monkeys and capuchin monkeys have some core abilities to represent some of the fundamental properties of objects and agents, comparable to those demonstrated by human infants, which supports the core knowledge view that such representational systems may have a long evolutionary history and exist widely in primates.The influence of social dynamics on the gestural communication of East African chimpanzeesBadihi, Galhttps://hdl.handle.net/10023/289782024-01-16T03:06:12Z2024-06-10T00:00:00ZGreat apes use gestural communication flexibly and intentionally to request a range of goals across diverse social contexts. The cognitive capacities required for this communication system have been compared to those underlying human language, leading some to suggest a gestural origin to linguistic communication. Both human language and great ape gesture have evolved within rich social systems. Humans adjust their use of language to specific social situations – accommodating to specific recipients or conforming to local dialects. However, the influences of social dynamics on great ape gestural communication remain highly understudied. To address this gap, I explore how individual identity, the relationship between signaller and recipient, and community membership impacts the use of specific gesture units, gesture expression, and the timing of communication across five communities of wild East African chimpanzees (Pan troglodytes schweinfurthii).
The overall structure of gestural interactions – the timing between signal and response – and the broad repertoire of gesture units was consistent across communities, suggesting that chimpanzees inherit the broad strokes of their communication as a species-typical system. Nevertheless, chimpanzees also conform to community specific preferences for regularly used gesture units and in the expression of specific gesture shapes. Signallers used different gesture units and gesture shapes depending on their social relationship to the recipient – most notably their kinship and sex relationships. Recipients also adjusted their latency to respond to specific signallers, responding faster to individuals with whom they shared weaker (less predictable) social bonds. Like humans, chimpanzees appear to conform to local dialects and adjust their gesture communication to accommodate specific communicative partners. These findings reveal previously hidden layers of social cognition used by chimpanzees during gestural communication; the decisions they make, and the distinct roles that signallers and recipients play when entering a gestural interaction.
2024-06-10T00:00:00ZBadihi, GalGreat apes use gestural communication flexibly and intentionally to request a range of goals across diverse social contexts. The cognitive capacities required for this communication system have been compared to those underlying human language, leading some to suggest a gestural origin to linguistic communication. Both human language and great ape gesture have evolved within rich social systems. Humans adjust their use of language to specific social situations – accommodating to specific recipients or conforming to local dialects. However, the influences of social dynamics on great ape gestural communication remain highly understudied. To address this gap, I explore how individual identity, the relationship between signaller and recipient, and community membership impacts the use of specific gesture units, gesture expression, and the timing of communication across five communities of wild East African chimpanzees (Pan troglodytes schweinfurthii).
The overall structure of gestural interactions – the timing between signal and response – and the broad repertoire of gesture units was consistent across communities, suggesting that chimpanzees inherit the broad strokes of their communication as a species-typical system. Nevertheless, chimpanzees also conform to community specific preferences for regularly used gesture units and in the expression of specific gesture shapes. Signallers used different gesture units and gesture shapes depending on their social relationship to the recipient – most notably their kinship and sex relationships. Recipients also adjusted their latency to respond to specific signallers, responding faster to individuals with whom they shared weaker (less predictable) social bonds. Like humans, chimpanzees appear to conform to local dialects and adjust their gesture communication to accommodate specific communicative partners. These findings reveal previously hidden layers of social cognition used by chimpanzees during gestural communication; the decisions they make, and the distinct roles that signallers and recipients play when entering a gestural interaction.Selective attention and flexible learning in ratsKnott, Tegan Saskiahttps://hdl.handle.net/10023/289622024-01-06T03:07:30Z2024-06-10T00:00:00ZAbstract redacted
2024-06-10T00:00:00ZKnott, Tegan SaskiaAbstract redactedCommonalities and group differences in the communicative efficiency of chimpanzee gesturingSafryghin, Alexandrahttps://hdl.handle.net/10023/289442024-01-05T14:03:28Z2024-06-10T00:00:00ZIn animal communication research, there is a keen interest in assessing and comparing the efficiency of communication systems with human languages. Yet, the gestural communication of our closest relatives, chimpanzees, remains underexplored. This thesis addresses this gap by investigating communicative efficiency in gestural communication across three chimpanzee communities: Sonso and Waibira in East Africa (Uganda) and Bossou in West Africa (Guinea). Employing a novel coding scheme and diverse gesture duration metrics, I examine the presence of Zipf's law of brevity and Menzerath's law, commonly expressed principles of communicative efficiency in human language, in chimpanzee gesturing. In addition, I directly assess the optimality of chimpanzee gestures using a novel linguistic metric from human language comparisons. I explore variations in gesture durations and sequence usage based on individual and social characteristics, such as familiarity, gender, age, and rank. Across these measures, a clear pattern emerges: Each chimpanzee community exhibits a distinct communicative style closely tied to their socio-ecological context. Remarkably, gestures in Bossou, the most cohesive community, demonstrate the first confirmed presence of Zipf's law of brevity and Menzerath's law, along with gesture repertoire optimisation reaching the lower bound of the distribution represented in human languages. Conversely, Waibira, the largest but least cohesive community, employs gestures with redundancy, favouring short sequences and lengthy single gestures. Sonso falls between these extremes, both in community dynamics and communicative efficiency. A consistent finding is that, as familiarity increases, gesture durations also lengthen, suggesting closer social connections lead to reduced pressure to communicate quickly or efficiently. Ultimately, each community employs a different communication style, highlighting the flexible potential of chimpanzee gestures.
2024-06-10T00:00:00ZSafryghin, AlexandraIn animal communication research, there is a keen interest in assessing and comparing the efficiency of communication systems with human languages. Yet, the gestural communication of our closest relatives, chimpanzees, remains underexplored. This thesis addresses this gap by investigating communicative efficiency in gestural communication across three chimpanzee communities: Sonso and Waibira in East Africa (Uganda) and Bossou in West Africa (Guinea). Employing a novel coding scheme and diverse gesture duration metrics, I examine the presence of Zipf's law of brevity and Menzerath's law, commonly expressed principles of communicative efficiency in human language, in chimpanzee gesturing. In addition, I directly assess the optimality of chimpanzee gestures using a novel linguistic metric from human language comparisons. I explore variations in gesture durations and sequence usage based on individual and social characteristics, such as familiarity, gender, age, and rank. Across these measures, a clear pattern emerges: Each chimpanzee community exhibits a distinct communicative style closely tied to their socio-ecological context. Remarkably, gestures in Bossou, the most cohesive community, demonstrate the first confirmed presence of Zipf's law of brevity and Menzerath's law, along with gesture repertoire optimisation reaching the lower bound of the distribution represented in human languages. Conversely, Waibira, the largest but least cohesive community, employs gestures with redundancy, favouring short sequences and lengthy single gestures. Sonso falls between these extremes, both in community dynamics and communicative efficiency. A consistent finding is that, as familiarity increases, gesture durations also lengthen, suggesting closer social connections lead to reduced pressure to communicate quickly or efficiently. Ultimately, each community employs a different communication style, highlighting the flexible potential of chimpanzee gestures.Secondary bystandership: how primary bystanders influence the subsequent responses of othersRocha Santa María, Carolina Alejandrahttps://hdl.handle.net/10023/286222023-11-03T03:03:00Z2023-11-29T00:00:00ZThe aim of this thesis is providing new insights into the social influence processes that take place between bystanders. Specifically, this manuscript presents research that explores whether the perception of group norms is the key process that allows bystanders’ actions to influence the subsequent behaviour of other bystanders.
This question is addressed with a multi-method approach. Studies 1 and 2 are online-survey experiments conducted during the COVID-19 pandemic in the United Kingdom (UK). They suggest that seeing ingroup members looking after others does not promote bystanders’ willingness to do the same when group norms already prescribe helping. Studies 3, 4, and 5 are online-survey experiments focused on Britons’ willingness to help asylum seekers and refugees. These studies suggest that when whether to help and how to help are contested issues, active bystandership inspires further solidarity. This phenomenon involves normative influence but also other processes, such as the perceived seriousness of the situation and bystanders’ sense of self-efficacy. Finally, Study 6 is an interview study conducted during a harshly repressed social uprising in Chile. This study shows that the shape and magnitude of social influence between bystanders vary over the evolution of emergencies.
This thesis argues that bystandership involves complex sense-making processes where the behaviour of other bystanders is one of multiple tools that bystanders can use to conclude what is happening, what should be done, whether they should help, and what they are capable of. Their conclusions may also be informed by other inputs, such as lessons from their personal and social history, their social identities, pre-existing group norms, and the resources and skills that they have. Thus, social influence between bystanders is presented here as a phenomenon shaped by history, time, reflexive processes, and socially mediated perceptions of reality.
2023-11-29T00:00:00ZRocha Santa María, Carolina AlejandraThe aim of this thesis is providing new insights into the social influence processes that take place between bystanders. Specifically, this manuscript presents research that explores whether the perception of group norms is the key process that allows bystanders’ actions to influence the subsequent behaviour of other bystanders.
This question is addressed with a multi-method approach. Studies 1 and 2 are online-survey experiments conducted during the COVID-19 pandemic in the United Kingdom (UK). They suggest that seeing ingroup members looking after others does not promote bystanders’ willingness to do the same when group norms already prescribe helping. Studies 3, 4, and 5 are online-survey experiments focused on Britons’ willingness to help asylum seekers and refugees. These studies suggest that when whether to help and how to help are contested issues, active bystandership inspires further solidarity. This phenomenon involves normative influence but also other processes, such as the perceived seriousness of the situation and bystanders’ sense of self-efficacy. Finally, Study 6 is an interview study conducted during a harshly repressed social uprising in Chile. This study shows that the shape and magnitude of social influence between bystanders vary over the evolution of emergencies.
This thesis argues that bystandership involves complex sense-making processes where the behaviour of other bystanders is one of multiple tools that bystanders can use to conclude what is happening, what should be done, whether they should help, and what they are capable of. Their conclusions may also be informed by other inputs, such as lessons from their personal and social history, their social identities, pre-existing group norms, and the resources and skills that they have. Thus, social influence between bystanders is presented here as a phenomenon shaped by history, time, reflexive processes, and socially mediated perceptions of reality. The role of the lateral entorhinal-hippocampal network in episodic(-like) memory and Alzheimer's diseaseAmbrozova, Veronikahttps://hdl.handle.net/10023/285772023-11-01T03:06:06Z2023-11-29T00:00:00ZAbstract redacted
2023-11-29T00:00:00ZAmbrozova, VeronikaAbstract redactedAs easy as ABC? A novel psychological approach to teacher agency: exploring the influence of affect on behaviour and cognitionPorter, Karenhttps://hdl.handle.net/10023/283762023-09-15T02:07:04Z2023-11-29T00:00:00ZDespite recognition that agency matters for teachers’ effective performance, psychological theories underlying agency have not been clearly established to date. This thesis addresses the deficit in understanding teachers’ choices to act by examining potential constructs related to agency. The thesis begins by reviewing existing theories of agency, motivation and emotions, and highlighting issues with existing research. Next, four studies are described. The first involved thematic analysis of interviews with thirteen teachers in Scottish schools about their experience of teaching during the Covid-19 pandemic. The second study surveyed 500 teachers using standardised questionnaires related to emotion, self-efficacy and agency, and resulting data were analysed using structural equation modelling and latent profile analysis. The third study involved interviewing seven teachers over four months to consider the impact of awareness of emotion on their beliefs and actions. The fourth study involved reflection on the author’s experiences as a student, teacher and researcher, examining relationships between emotional experiences, beliefs and actions. Emerging findings included that: (i) the emotional percepts of CARE, CURIOSITY, COOPERATION and CHALLENGE individually and collectively influenced teachers’ beliefs about their efficacy and choices available to them to act; (ii) deliberate inaction and collective action are forms of agency; (iii) individual differences in levels and patterns of emotional percepts reflect self-efficacy and agency levels; (iv) modes of agency differ depending on teachers’ beliefs about choices available for action; and (v) awareness of percepts facilitates reflection, leading to cognitive and behavioural change, notably improved self-care. Theory is advanced by identifying the role of emotional percepts as a route to, or driver of, teacher agency, proposing awareness of emotional experience as an effective route to action. Findings offer the potential to improve teachers’ agency as continuing changes in circumstances affect them and their students. Future studies should examine practical benefits of the theory for teachers and students.
2023-11-29T00:00:00ZPorter, KarenDespite recognition that agency matters for teachers’ effective performance, psychological theories underlying agency have not been clearly established to date. This thesis addresses the deficit in understanding teachers’ choices to act by examining potential constructs related to agency. The thesis begins by reviewing existing theories of agency, motivation and emotions, and highlighting issues with existing research. Next, four studies are described. The first involved thematic analysis of interviews with thirteen teachers in Scottish schools about their experience of teaching during the Covid-19 pandemic. The second study surveyed 500 teachers using standardised questionnaires related to emotion, self-efficacy and agency, and resulting data were analysed using structural equation modelling and latent profile analysis. The third study involved interviewing seven teachers over four months to consider the impact of awareness of emotion on their beliefs and actions. The fourth study involved reflection on the author’s experiences as a student, teacher and researcher, examining relationships between emotional experiences, beliefs and actions. Emerging findings included that: (i) the emotional percepts of CARE, CURIOSITY, COOPERATION and CHALLENGE individually and collectively influenced teachers’ beliefs about their efficacy and choices available to them to act; (ii) deliberate inaction and collective action are forms of agency; (iii) individual differences in levels and patterns of emotional percepts reflect self-efficacy and agency levels; (iv) modes of agency differ depending on teachers’ beliefs about choices available for action; and (v) awareness of percepts facilitates reflection, leading to cognitive and behavioural change, notably improved self-care. Theory is advanced by identifying the role of emotional percepts as a route to, or driver of, teacher agency, proposing awareness of emotional experience as an effective route to action. Findings offer the potential to improve teachers’ agency as continuing changes in circumstances affect them and their students. Future studies should examine practical benefits of the theory for teachers and students.Sex/gender differences in romantic jealousy in the UK and China : integrating social-cognitive and evolutionary approachesZhou, Mengxiaohttps://hdl.handle.net/10023/282102023-09-04T16:11:04Z2023-11-29T00:00:00ZMen and women differ in experiencing romantic jealousy: men are more distressed by sexual infidelity, women by emotional infidelity; men are more distressed by rivals surpassing themselves in attainment of resources, women by those who are more attractive. Evolutionary psychology proposes evolved sex-differentiated jealousy mechanisms, whereas cultural constructionism proposes effects of culturally ascribed meanings to men and women. This thesis explores gender differences in romantic jealousy in UK and Chinese populations from both theoretical perspectives, as well as other potential factors not pre-defined in previous research.
Chapter Three tests EP predictions of sex difference in jealousy response to sexual versus emotional infidelity, and the social cognitive prediction that men and women’s different interpretations of infidelity—which type of infidelity is more likely to imply co-occurrence of both types-- create the gender difference. On-line survey responses from UK and Chinese non-student samples are analysed. With t-test and ANOVA, EP predicted sex effect is consistently found by the relative criterion but not by the stringent criterion. With mediation analyses, men and women’s different interpretations of infidelity are consistently found to mediate the overall gender differences.
Chapter Four tests EP predictions of sex differences in jealousy response to different rival traits, as well as predictions derived from the social cognitive perspective. On-line survey responses from UK and Chinese non-student samples are analysed. With ANOVA, EP predicted sex difference is consistently found only for traits related to attractiveness, but not to social and physical dominance. With mediation analyses, men and women’s different speculations about each other’s mate preferences are consistently found to mediate the overall gender differences.
Chapter Five presents a qualitative, bottom-up analysis of social media comments to celebrity affairs in the UK and China. Moral evaluations and attribution, both not directly related to the mating domain, are found to influence perceptions of infidelity. Relations to the Moral Foundations theory and attributional theory of jealousy are discussed.
The Conclusion Chapter discusses the results in relation to EP and cultural constructionist theories. Implications for an integrative, domain-overlapping account of human sexual psychology are discussed.
2023-11-29T00:00:00ZZhou, MengxiaoMen and women differ in experiencing romantic jealousy: men are more distressed by sexual infidelity, women by emotional infidelity; men are more distressed by rivals surpassing themselves in attainment of resources, women by those who are more attractive. Evolutionary psychology proposes evolved sex-differentiated jealousy mechanisms, whereas cultural constructionism proposes effects of culturally ascribed meanings to men and women. This thesis explores gender differences in romantic jealousy in UK and Chinese populations from both theoretical perspectives, as well as other potential factors not pre-defined in previous research.
Chapter Three tests EP predictions of sex difference in jealousy response to sexual versus emotional infidelity, and the social cognitive prediction that men and women’s different interpretations of infidelity—which type of infidelity is more likely to imply co-occurrence of both types-- create the gender difference. On-line survey responses from UK and Chinese non-student samples are analysed. With t-test and ANOVA, EP predicted sex effect is consistently found by the relative criterion but not by the stringent criterion. With mediation analyses, men and women’s different interpretations of infidelity are consistently found to mediate the overall gender differences.
Chapter Four tests EP predictions of sex differences in jealousy response to different rival traits, as well as predictions derived from the social cognitive perspective. On-line survey responses from UK and Chinese non-student samples are analysed. With ANOVA, EP predicted sex difference is consistently found only for traits related to attractiveness, but not to social and physical dominance. With mediation analyses, men and women’s different speculations about each other’s mate preferences are consistently found to mediate the overall gender differences.
Chapter Five presents a qualitative, bottom-up analysis of social media comments to celebrity affairs in the UK and China. Moral evaluations and attribution, both not directly related to the mating domain, are found to influence perceptions of infidelity. Relations to the Moral Foundations theory and attributional theory of jealousy are discussed.
The Conclusion Chapter discusses the results in relation to EP and cultural constructionist theories. Implications for an integrative, domain-overlapping account of human sexual psychology are discussed.Title redactedUluşahin, Yaseminhttps://hdl.handle.net/10023/281272024-02-01T22:08:08Z2023-11-29T00:00:00ZAbstract redacted
2023-11-29T00:00:00ZUluşahin, YaseminAbstract redactedInvestigating the early changes in intrinsic properties and synaptic inputs in the vulnerable fast-type motoneurons of SOD1ᴳ⁹³ᴬ mouse model of Amyotrophic Lateral SclerosisGnanasampanthan, Arauthy Ginahttps://hdl.handle.net/10023/281092024-01-05T12:27:45Z2023-11-29T00:00:00ZAmyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterised by the deterioration of upper and lower motoneurons (MNs), which leads to paralysis and death. Pathophysiological alterations in MN output have been shown at early postnatal stages in ALS model mice; however, it is unclear whether these changes are due to alterations in synaptic inputs or intrinsic MN properties. Here, we investigated the mechanisms contributing to altered MN output by using whole-cell patch clamp electrophysiology to study MN properties and synaptic inputs to MNs during the first two postnatal weeks in the SOD1ᴳ⁹³ᴬ mouse model of ALS. Our study targeted delayed firing, fast- type lumbar MNs that are vulnerable and degenerate in ALS. We observed increases in the frequency of mixed postsynaptic currents (PSCs) received by SOD1ᴳ⁹³ᴬ MNs and application of tetrodotoxin also showed increased frequency of action-potential independent miniature PSCs (mPSCs). When pharmacologically characterising the origin of mPSC, we observed a decrease in excitatory mPSC frequency and increases in both frequency and amplitude of inhibitory mPSC in fast-type SOD1ᴳ⁹³ᴬ MN.
Analysis of MN intrinsic properties, including capacitance, rheobase, persistent inward currents and post-discharge activity, revealed no significant changes in fast-type MNs of SOD1ᴳ⁹³ᴬ mice. However, a significant increase in the hyperpolarisation-activated inward current (Ih), an important factor driving recruitment and rebound depolarisation, was observed in two-week-old SOD1ᴳ⁹³ᴬ mice. Next, we investigated the distribution of excitatory and inhibitory post-synaptic density (PSDs) and their subsynaptic nanoclusters (NCs) in motoneuron rich area of lamina IX of SOD1ᴳ⁹³ᴬ mice. Super-resolution microscopy revealed decreases in both excitatory and inhibitory NCs size in SOD1ᴳ⁹³ᴬ. We found that although the density of inhibitory PSD is lower in the SOD1ᴳ⁹³ᴬ, there was no difference in the excitatory: inhibitory ratio (E:I) in the second postnatal week of SOD1ᴳ⁹³ᴬ mice.
Overall, early postnatal changes observed in synaptic inputs demonstrate an early role for synaptic dysfunction in SOD1 ALS. Changes in Ih and synaptic inputs may both contribute to improper MN output as the disease progresses. These early changes together could set up the neuronal network for failure which could lead to progressive degeneration of spinal MNs in SOD1ᴳ⁹³ᴬ ALS.
2023-11-29T00:00:00ZGnanasampanthan, Arauthy GinaAmyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease characterised by the deterioration of upper and lower motoneurons (MNs), which leads to paralysis and death. Pathophysiological alterations in MN output have been shown at early postnatal stages in ALS model mice; however, it is unclear whether these changes are due to alterations in synaptic inputs or intrinsic MN properties. Here, we investigated the mechanisms contributing to altered MN output by using whole-cell patch clamp electrophysiology to study MN properties and synaptic inputs to MNs during the first two postnatal weeks in the SOD1ᴳ⁹³ᴬ mouse model of ALS. Our study targeted delayed firing, fast- type lumbar MNs that are vulnerable and degenerate in ALS. We observed increases in the frequency of mixed postsynaptic currents (PSCs) received by SOD1ᴳ⁹³ᴬ MNs and application of tetrodotoxin also showed increased frequency of action-potential independent miniature PSCs (mPSCs). When pharmacologically characterising the origin of mPSC, we observed a decrease in excitatory mPSC frequency and increases in both frequency and amplitude of inhibitory mPSC in fast-type SOD1ᴳ⁹³ᴬ MN.
Analysis of MN intrinsic properties, including capacitance, rheobase, persistent inward currents and post-discharge activity, revealed no significant changes in fast-type MNs of SOD1ᴳ⁹³ᴬ mice. However, a significant increase in the hyperpolarisation-activated inward current (Ih), an important factor driving recruitment and rebound depolarisation, was observed in two-week-old SOD1ᴳ⁹³ᴬ mice. Next, we investigated the distribution of excitatory and inhibitory post-synaptic density (PSDs) and their subsynaptic nanoclusters (NCs) in motoneuron rich area of lamina IX of SOD1ᴳ⁹³ᴬ mice. Super-resolution microscopy revealed decreases in both excitatory and inhibitory NCs size in SOD1ᴳ⁹³ᴬ. We found that although the density of inhibitory PSD is lower in the SOD1ᴳ⁹³ᴬ, there was no difference in the excitatory: inhibitory ratio (E:I) in the second postnatal week of SOD1ᴳ⁹³ᴬ mice.
Overall, early postnatal changes observed in synaptic inputs demonstrate an early role for synaptic dysfunction in SOD1 ALS. Changes in Ih and synaptic inputs may both contribute to improper MN output as the disease progresses. These early changes together could set up the neuronal network for failure which could lead to progressive degeneration of spinal MNs in SOD1ᴳ⁹³ᴬ ALS.Chimpanzee (Pan troglodytes) cognitive mechanisms for joint action and virtual environment navigationMcEwen, Emma Suvihttps://hdl.handle.net/10023/279582023-07-15T02:06:41Z2023-11-29T00:00:00ZChimpanzees have demonstrated across several experimental studies and field observations that they can successfully work together. The cognitive mechanisms that chimpanzees employ for joint action, however, remain unclear. A key component of human co-ordination is the ability to represent not only one’s own role, but also the role of a partner. In the first two studies presented, I report evidence that chimpanzees may also represent a partner’s actions during joint action. First, I present evidence that chimpanzees accommodate an experimenter’s actions when passing an object, possibly incorporating another’s actions into their own action plans. Second, I present evidence that chimpanzees learn about a partner’s actions, which may facilitate their ability to produce those actions themselves in a partial role-reversal task. Another open question about chimpanzee joint action is the motivation behind choosing to work together or alone. To investigate whether physical effort may influence chimpanzees’ apparatus choices, I present evidence from a task in which chimpanzees chose between a high and low effort puzzle-box apparatus. Chimpanzees showed no preference for either apparatus. There is also a spatial component to joint action, and how the action space is represented may affect perspective taking and how others’ actions are represented. In the final experiment, I examined chimpanzee’s spatial frames of reference in a virtual environment task. The results showed that some subjects used a simple landmark as an allocentric cue, but not more distal landmarks. Learning about how chimpanzees represent virtual spaces, and whether they could conceive of alternative perspectives, is an important first step towards virtual cooperative games with captive primates. The results of this thesis suggest that chimpanzees understand the role of their partner during joint action, may not reduce their own effort, are sometimes able to use simple virtual landmarks, and can find out-of-sight food in a virtual environment.
2023-11-29T00:00:00ZMcEwen, Emma SuviChimpanzees have demonstrated across several experimental studies and field observations that they can successfully work together. The cognitive mechanisms that chimpanzees employ for joint action, however, remain unclear. A key component of human co-ordination is the ability to represent not only one’s own role, but also the role of a partner. In the first two studies presented, I report evidence that chimpanzees may also represent a partner’s actions during joint action. First, I present evidence that chimpanzees accommodate an experimenter’s actions when passing an object, possibly incorporating another’s actions into their own action plans. Second, I present evidence that chimpanzees learn about a partner’s actions, which may facilitate their ability to produce those actions themselves in a partial role-reversal task. Another open question about chimpanzee joint action is the motivation behind choosing to work together or alone. To investigate whether physical effort may influence chimpanzees’ apparatus choices, I present evidence from a task in which chimpanzees chose between a high and low effort puzzle-box apparatus. Chimpanzees showed no preference for either apparatus. There is also a spatial component to joint action, and how the action space is represented may affect perspective taking and how others’ actions are represented. In the final experiment, I examined chimpanzee’s spatial frames of reference in a virtual environment task. The results showed that some subjects used a simple landmark as an allocentric cue, but not more distal landmarks. Learning about how chimpanzees represent virtual spaces, and whether they could conceive of alternative perspectives, is an important first step towards virtual cooperative games with captive primates. The results of this thesis suggest that chimpanzees understand the role of their partner during joint action, may not reduce their own effort, are sometimes able to use simple virtual landmarks, and can find out-of-sight food in a virtual environment.The experience of women in undergraduate physics : a proposed imposter phenomenon interventionBottomley, Ewanhttps://hdl.handle.net/10023/278822023-11-06T13:56:59Z2023-11-29T00:00:00ZAcross four studies (three quantitative and one qualitative) this thesis examines the experience of women in physics. Prior research has demonstrated gender differences amongst physicists in the perceptions of self-efficacy, belonging, perceived recognition as a physicist, and physics identity. This research suggests that men report being more confident in their abilities in physics, feeling like they belong to a greater degree, feeling more recognised as a physicist by others, and seeing themselves as a physicist to a greater extent than women. Building on these findings, I examined whether gender differences in these constructs could predict academic outcomes (specifically: academic performance (Chapter 2), identification with physics as a discipline (Chapter 3), and students’ sense of wellbeing (Chapter 4)). The results of these Chapters replicated the gender differences in physics identity, perceived recognition as a physicist, and self-efficacy, with women reporting lower levels compared to men. The results also found that self-efficacy was a strong predictor of academic performance and wellbeing for both men and women. However, to gain a deeper understanding of the problems facing women, and the ways in which I could begin to address these problems, I ran some semi-structured interviews (Chapter 5). The interviews provided support for our quantitative data, with women reporting that they doubted their abilities in physics and regularly reported imposter phenomenon. To address questions of self-doubt and imposter phenomenon I created a short imposter phenomenon intervention (Chapter 6) which focused on trying to normalise the discussion around imposter phenomenon in the physics classroom, encouraging students to reach out for help if they required it. The intervention received positive feedback in follow-up interviews; however, further development and a more comprehensive assessment of the intervention is required. This thesis takes initial steps in trying to address some of the major problems facing women in undergraduate physics.
2023-11-29T00:00:00ZBottomley, EwanAcross four studies (three quantitative and one qualitative) this thesis examines the experience of women in physics. Prior research has demonstrated gender differences amongst physicists in the perceptions of self-efficacy, belonging, perceived recognition as a physicist, and physics identity. This research suggests that men report being more confident in their abilities in physics, feeling like they belong to a greater degree, feeling more recognised as a physicist by others, and seeing themselves as a physicist to a greater extent than women. Building on these findings, I examined whether gender differences in these constructs could predict academic outcomes (specifically: academic performance (Chapter 2), identification with physics as a discipline (Chapter 3), and students’ sense of wellbeing (Chapter 4)). The results of these Chapters replicated the gender differences in physics identity, perceived recognition as a physicist, and self-efficacy, with women reporting lower levels compared to men. The results also found that self-efficacy was a strong predictor of academic performance and wellbeing for both men and women. However, to gain a deeper understanding of the problems facing women, and the ways in which I could begin to address these problems, I ran some semi-structured interviews (Chapter 5). The interviews provided support for our quantitative data, with women reporting that they doubted their abilities in physics and regularly reported imposter phenomenon. To address questions of self-doubt and imposter phenomenon I created a short imposter phenomenon intervention (Chapter 6) which focused on trying to normalise the discussion around imposter phenomenon in the physics classroom, encouraging students to reach out for help if they required it. The intervention received positive feedback in follow-up interviews; however, further development and a more comprehensive assessment of the intervention is required. This thesis takes initial steps in trying to address some of the major problems facing women in undergraduate physics.The developmental origins of joint attention in infancySalter, Gideonhttps://hdl.handle.net/10023/278002023-06-21T14:40:04Z2022-11-29T00:00:00ZDespite widespread recognition of the importance of joint attention, there are still disagreements regarding its definition and development. There are questions over when and how joint attention emerges, what exactly makes it joint, and its relation to communication. These developmental and definitional questions are closely linked, and thus to understand joint attention we must understand the very beginnings of its development and its relation to communication. This thesis aimed to further our understanding of joint attention by investigating infants’ development in the key period leading up to 9 months.
The thesis reports a comprehensive longitudinal study of infants aged 6 to 10 months (with additional data collected remotely at 11 and 12 months), using experimental, observational, interview and questionnaire methods. First, it investigated the very beginnings of infants’ capacity to initiate joint attention, finding that this ability emerges for some infants by 6 months. Next, it examined the very beginnings of infants’ gestural communication, identifying developmental processes that precede the emergence of some of infants’ earliest conventional communicative gestures. It also examined a range of other social (e.g. imitation), cognitive (e.g. means-ends understanding) and motor skills (e.g. self-locomotion) in order to identify relations between key social and non-social abilities emerging in this period. These abilities typically emerged gradually, starting before 9 months, with limited relations found amongst them. Finally, the study examined the relations between maternal and researcher assessments of communication and motor skills, identifying ways to increase consistency between these assessments.
Overall, the thesis shines new light on the very beginnings of joint attention and communication in infancy. It demonstrates that infants’ capacity to engage in joint attention emerges for some infants by 6 months of age, and highlights the importance of investigating the processes that lead to the emergence of joint attention and communicative abilities.
2022-11-29T00:00:00ZSalter, GideonDespite widespread recognition of the importance of joint attention, there are still disagreements regarding its definition and development. There are questions over when and how joint attention emerges, what exactly makes it joint, and its relation to communication. These developmental and definitional questions are closely linked, and thus to understand joint attention we must understand the very beginnings of its development and its relation to communication. This thesis aimed to further our understanding of joint attention by investigating infants’ development in the key period leading up to 9 months.
The thesis reports a comprehensive longitudinal study of infants aged 6 to 10 months (with additional data collected remotely at 11 and 12 months), using experimental, observational, interview and questionnaire methods. First, it investigated the very beginnings of infants’ capacity to initiate joint attention, finding that this ability emerges for some infants by 6 months. Next, it examined the very beginnings of infants’ gestural communication, identifying developmental processes that precede the emergence of some of infants’ earliest conventional communicative gestures. It also examined a range of other social (e.g. imitation), cognitive (e.g. means-ends understanding) and motor skills (e.g. self-locomotion) in order to identify relations between key social and non-social abilities emerging in this period. These abilities typically emerged gradually, starting before 9 months, with limited relations found amongst them. Finally, the study examined the relations between maternal and researcher assessments of communication and motor skills, identifying ways to increase consistency between these assessments.
Overall, the thesis shines new light on the very beginnings of joint attention and communication in infancy. It demonstrates that infants’ capacity to engage in joint attention emerges for some infants by 6 months of age, and highlights the importance of investigating the processes that lead to the emergence of joint attention and communicative abilities.Enrichment-dependent effects on adult hippocampal neurogenesis, episodic-like memory and place cell activity throughout the lifespanVentura, Silviahttps://hdl.handle.net/10023/277952023-06-24T02:04:54Z2023-11-29T00:00:00ZAbstract redacted
2023-11-29T00:00:00ZVentura, SilviaAbstract redactedOstension, pragmatics, and presumptions of relevance : an investigation of communication cognition in non-human primatesWarren, Elizabethhttps://hdl.handle.net/10023/275582023-06-07T08:42:57Z2023-06-15T00:00:00ZA prominent debate in the study of non-human primate cognition concerns their level of cognitive engagement with communication, and especially their capacity for pragmatic and ostensive communication. I investigated this question across four experiments, probing non-human primates’ expectations in response to ostensive behaviour and their production of context-dependent, goal-directed gestures in a cooperative setting. In the first experiment, I examined whether chimpanzees (Pan troglodytes) moderated their object choice patterns based on their differentiation between ostensive and non-ostensive displays from me, a cooperative human partner. In the second experiment, I investigated whether seven species of non-human primates acquired an expectation of relevant information when they were addressed with ostensive communication, using their gaze-following behaviour as a measure. In the third experiment, I explored whether all four species of non-human great apes moderated their expectation of action from me following ostensive address, measured by their production of requesting behaviours. This experiment used varying emotional valences within the ostensive displays, in order to examine whether subjects were sensitive to the context-setting nature of emotional tone in communication. In the fourth experiment, I examined whether chimpanzees produced requesting behaviours pragmatically depending on their past experience with me as cooperative partner. The results from these four experiments showed that certain primates are sensitive to the presumption of relevance generated by ostensive behaviour, and that their responses to ostensive communication are moderated by factors such as emotional valence. These results did not suggest, however, that primates are able to compute specific informational meanings following ostensive communication, nor that they rely on mutual common ground to imbue their own communication with meaning. I interpret these findings in context with existing theories of pragmatic and ostensive communication and analyse some theoretical and empirical factors that make a paradigm suitable for the study of ostensive communication in non-human primates.
2023-06-15T00:00:00ZWarren, ElizabethA prominent debate in the study of non-human primate cognition concerns their level of cognitive engagement with communication, and especially their capacity for pragmatic and ostensive communication. I investigated this question across four experiments, probing non-human primates’ expectations in response to ostensive behaviour and their production of context-dependent, goal-directed gestures in a cooperative setting. In the first experiment, I examined whether chimpanzees (Pan troglodytes) moderated their object choice patterns based on their differentiation between ostensive and non-ostensive displays from me, a cooperative human partner. In the second experiment, I investigated whether seven species of non-human primates acquired an expectation of relevant information when they were addressed with ostensive communication, using their gaze-following behaviour as a measure. In the third experiment, I explored whether all four species of non-human great apes moderated their expectation of action from me following ostensive address, measured by their production of requesting behaviours. This experiment used varying emotional valences within the ostensive displays, in order to examine whether subjects were sensitive to the context-setting nature of emotional tone in communication. In the fourth experiment, I examined whether chimpanzees produced requesting behaviours pragmatically depending on their past experience with me as cooperative partner. The results from these four experiments showed that certain primates are sensitive to the presumption of relevance generated by ostensive behaviour, and that their responses to ostensive communication are moderated by factors such as emotional valence. These results did not suggest, however, that primates are able to compute specific informational meanings following ostensive communication, nor that they rely on mutual common ground to imbue their own communication with meaning. I interpret these findings in context with existing theories of pragmatic and ostensive communication and analyse some theoretical and empirical factors that make a paradigm suitable for the study of ostensive communication in non-human primates.Title redactedFrancis, Jacob Ridley Johnhttps://hdl.handle.net/10023/274322023-04-22T02:02:33Z2022-11-29T00:00:00ZAbstract redacted
2022-11-29T00:00:00ZFrancis, Jacob Ridley JohnAbstract redactedLeadership impression from the face across culturesMa, Jinghttps://hdl.handle.net/10023/273862024-01-18T16:40:38Z2022-06-17T00:00:00ZPeople agree on who should be a leader based solely on static facial images, and this naive judgement is found to predict actual leadership emergence. Although many impressions correlate with leadership success, the perceived characteristics can be mapped onto two or three dimensions: dominance, trustworthiness, and attractiveness. This thesis examines cultural differences in the association of personality judgements and leadership. Chapter 1 reviews the theoretical basis for the association between facial features and leadership, reviewing evolutionary, social identity, and leadership categorization theories. Chapters 2-4 present empirical studies of leadership impressions from the face. Chapter 2 found facial judgements of leadership can be grouped into two dimensions: a prototypical leadership dimension (sensitivity, dedication, charisma, attractiveness, intelligence, strength) and an anti-prototypical leadership dimension (tyranny, masculinity, and strength). Chapter 2 also found that leadership judgments are contextual and depend on the type of leader (business, sports, moral). Averages of faces seen as good sports leaders were rated highest on the anti-prototypical leadership dimension, while averages of faces seen as good moral leaders were rated highest on prototypical leadership dimension. Chapter 3 examined the impact of facial masculinity and prototypicality on leadership perception in UK and Chinese societies. Increase of prototypicality (own ethnicity in face shape) enhanced leadership perception, particularly in Chinese subjects. Increased facial masculinity decreased leadership perception for female faces, particularly in European subjects. Seeing one’s identity as one of a hierarchical group (collectivism) drove preference for masculinity in female leaders. Chapter 4 measured the leadership perception in real-world leadership within a Chinese corporation. The faces of male leaders were judged more mature, trustworthy, and competent looking but not more attractive than the non-leaders.
2022-06-17T00:00:00ZMa, JingPeople agree on who should be a leader based solely on static facial images, and this naive judgement is found to predict actual leadership emergence. Although many impressions correlate with leadership success, the perceived characteristics can be mapped onto two or three dimensions: dominance, trustworthiness, and attractiveness. This thesis examines cultural differences in the association of personality judgements and leadership. Chapter 1 reviews the theoretical basis for the association between facial features and leadership, reviewing evolutionary, social identity, and leadership categorization theories. Chapters 2-4 present empirical studies of leadership impressions from the face. Chapter 2 found facial judgements of leadership can be grouped into two dimensions: a prototypical leadership dimension (sensitivity, dedication, charisma, attractiveness, intelligence, strength) and an anti-prototypical leadership dimension (tyranny, masculinity, and strength). Chapter 2 also found that leadership judgments are contextual and depend on the type of leader (business, sports, moral). Averages of faces seen as good sports leaders were rated highest on the anti-prototypical leadership dimension, while averages of faces seen as good moral leaders were rated highest on prototypical leadership dimension. Chapter 3 examined the impact of facial masculinity and prototypicality on leadership perception in UK and Chinese societies. Increase of prototypicality (own ethnicity in face shape) enhanced leadership perception, particularly in Chinese subjects. Increased facial masculinity decreased leadership perception for female faces, particularly in European subjects. Seeing one’s identity as one of a hierarchical group (collectivism) drove preference for masculinity in female leaders. Chapter 4 measured the leadership perception in real-world leadership within a Chinese corporation. The faces of male leaders were judged more mature, trustworthy, and competent looking but not more attractive than the non-leaders.Enhancing vision : a project on audio-visual decision-making, and a project on strengthening the visual system by short-term monocular patchingChua, Siu Fung Andrewhttps://hdl.handle.net/10023/273802023-04-12T12:00:09Z2023-06-15T00:00:00ZVision is important; two projects were conducted to explore the enhancement of vision (multisensory combination, novel procedure to improve visual functioning). In the first project, audition was combined with vision, to examine if the conjunction of two sensory modalities benefits sensory decision-making in the context of looming – a potentially dangerous motion requiring quick responses (e.g., Neuhoff, 2001). Four behavioural experiments were conducted, testing responses towards auditory, visual, or audio-visual motion-in-depth signals (i.e., looming or receding). From behavioural data, the decision-making mechanism was explored in two separate analyses: 1) a comparative approach (e.g., Innes & Otto, 2019) which compared empirical data to predictions made using probability summation (Raab, 1962), and 2) a computational modelling approach which determined the best permutation of an interactive probability summation rule (Otto & Mamassian, 2012) to fit the empirical data. Altogether, the first project revealed that decision-making had a speed benefit when auditory and visual signals were both present, compared to either modality alone, and this benefit could be explained by a probability summation rule with simple audio-visual interactions. Not found was evidence of especially quick processing uniquely towards audio-visual looming signals. For the second research direction, a pilot study was conducted to test a novel short-term monocular patching technique which purportedly induces eye dominance via latent neuroplasticity (e.g., Lunghi, Burr, & Morrone, 2011), with the idea that it could become a procedure for improving amblyopic visual functioning. In one small-scale experiment (n=4), a significant dominance effect on the patched eye was found, but the effect was short-lived. Two single-participant experiments indicated that patching durations should not be too short (10 minutes) and stereopsis sensitivity may slightly change after patching. This pilot study offered a preliminary look into patching effects, on the back of which further experiments are suggested.
2023-06-15T00:00:00ZChua, Siu Fung AndrewVision is important; two projects were conducted to explore the enhancement of vision (multisensory combination, novel procedure to improve visual functioning). In the first project, audition was combined with vision, to examine if the conjunction of two sensory modalities benefits sensory decision-making in the context of looming – a potentially dangerous motion requiring quick responses (e.g., Neuhoff, 2001). Four behavioural experiments were conducted, testing responses towards auditory, visual, or audio-visual motion-in-depth signals (i.e., looming or receding). From behavioural data, the decision-making mechanism was explored in two separate analyses: 1) a comparative approach (e.g., Innes & Otto, 2019) which compared empirical data to predictions made using probability summation (Raab, 1962), and 2) a computational modelling approach which determined the best permutation of an interactive probability summation rule (Otto & Mamassian, 2012) to fit the empirical data. Altogether, the first project revealed that decision-making had a speed benefit when auditory and visual signals were both present, compared to either modality alone, and this benefit could be explained by a probability summation rule with simple audio-visual interactions. Not found was evidence of especially quick processing uniquely towards audio-visual looming signals. For the second research direction, a pilot study was conducted to test a novel short-term monocular patching technique which purportedly induces eye dominance via latent neuroplasticity (e.g., Lunghi, Burr, & Morrone, 2011), with the idea that it could become a procedure for improving amblyopic visual functioning. In one small-scale experiment (n=4), a significant dominance effect on the patched eye was found, but the effect was short-lived. Two single-participant experiments indicated that patching durations should not be too short (10 minutes) and stereopsis sensitivity may slightly change after patching. This pilot study offered a preliminary look into patching effects, on the back of which further experiments are suggested.The effects of developmental stress on circadian rhythm ontogeny and the expression of diurnal behavioursHarvey-Carroll, Jessica-Lilyhttps://hdl.handle.net/10023/270852023-11-21T03:03:32Z2022-11-29T00:00:00ZAbstract redacted
2022-11-29T00:00:00ZHarvey-Carroll, Jessica-LilyAbstract redactedVarieties of common ground : common knowledge, common ignorance, and co-presenceLiu, Hao Lucyhttps://hdl.handle.net/10023/270822024-01-06T03:02:49Z2022-11-29T00:00:00ZCommon ground is seen as the basis for human communication and cooperation. Within common ground research, the main focus has always been on the knowledge that partners know together, i.e., "common knowledge". However, this neglects the factor of ignorance, which must be considered to be an integral component of common ground. To fill in this gap, different aspects of common ground (common knowledge, common ignorance, common privileged knowledge/ignorance) were investigated with a new coordination game in children between 4 and 8 years old. Results showed that common ignorance and common privileged ignorance were more difficult than common knowledge and common privileged knowledge: It was only by age 6 that children could use common ignorance at an equivalent level with common knowledge, and they had difficulty with “common privileged other knowledge” (i.e. self ignorance) even until age 8. Children’s understanding of ignorance was further probed with a preliminary investigation of strategic ignorance in children. As young as 4 years of age, children reported that they could actively choose not to know something, and from 5 years of age, adult-like reasons were given for things they preferred not to know. Common ground goes beyond common knowledge and ignorance states, and can also involve a feeling of co-presence. Whether physical co-presence in video calls could be simulated by partners using the same virtual background was investigated in an online study of adults. Results showed that using the same, as opposed to a different, background in video calls could enhance partners’ feelings of connectedness to some extent: They used a higher proportion of “we” pronouns, though they did not show a difference on other measurements such as perspective taking or mimicry. Taken together, this thesis contributes new knowledge about neglected aspects of common ground: the importance of common ignorance and its interplay with common knowledge in development, and the importance of markers of co-presence in the shared experience of online social interactions.
2022-11-29T00:00:00ZLiu, Hao LucyCommon ground is seen as the basis for human communication and cooperation. Within common ground research, the main focus has always been on the knowledge that partners know together, i.e., "common knowledge". However, this neglects the factor of ignorance, which must be considered to be an integral component of common ground. To fill in this gap, different aspects of common ground (common knowledge, common ignorance, common privileged knowledge/ignorance) were investigated with a new coordination game in children between 4 and 8 years old. Results showed that common ignorance and common privileged ignorance were more difficult than common knowledge and common privileged knowledge: It was only by age 6 that children could use common ignorance at an equivalent level with common knowledge, and they had difficulty with “common privileged other knowledge” (i.e. self ignorance) even until age 8. Children’s understanding of ignorance was further probed with a preliminary investigation of strategic ignorance in children. As young as 4 years of age, children reported that they could actively choose not to know something, and from 5 years of age, adult-like reasons were given for things they preferred not to know. Common ground goes beyond common knowledge and ignorance states, and can also involve a feeling of co-presence. Whether physical co-presence in video calls could be simulated by partners using the same virtual background was investigated in an online study of adults. Results showed that using the same, as opposed to a different, background in video calls could enhance partners’ feelings of connectedness to some extent: They used a higher proportion of “we” pronouns, though they did not show a difference on other measurements such as perspective taking or mimicry. Taken together, this thesis contributes new knowledge about neglected aspects of common ground: the importance of common ignorance and its interplay with common knowledge in development, and the importance of markers of co-presence in the shared experience of online social interactions.The functional significance of the sodium-potassium pump in motor control and movement disordersSorrell, Francesca Leighhttps://hdl.handle.net/10023/270772023-03-14T12:00:41Z2022-11-29T00:00:00ZThe sodium-potassium pump (NKA) is a ubiquitously expressed membrane protein. Mammalian neurons express two isoforms of the NKA’s catalytic α-subunit, the ubiquitous α1, and the neuron-specific α3. Mutations in the α3-NKA encoding protein ATP1A3 result in a spectrum of neurological disorders with pronounced motor deficits, including Rapid-Onset Dystonia Parkinsonism (RDP). The NKA has also been shown to facilitate activity-dependent changes in spinal motor networks via an ultra-slow afterhyperpolarisation (usAHP) which is thought to be an α3-NKA mediated current.
First, we provide a comprehensive characterisation of a novel mouse model of RDP harbouring the T613M mutation of ATP1A3 most commonly found in patients. We show that T613M animals are hyperactive and hyperambulatory. We show involvement of spinal motor circuit pathology in this behaviour via a complete lack of usAHPs in T613M-affected motor neurons, and a reduced capacity for isolated spinal cords to regulate rhythmic motor output in response to large increases of intracellular sodium. We show that this deficiency is likely caused by a reduced capacity for T613M-affected α3-NKA to extrude sodium and therefore maintain sodium homeostasis.
Next, we characterised post-discharge activity more generally in motor neurons from wildtype mice. We show that usAHPs are more commonly observed in the second postnatal week which may be due to an upregulation of α3-NKA protein expression in motor neurons alongside the development of weight-bearing locomotion. While the heterogenous distribution of usAHPs amongst populations of neurons was previously thought to be due to mosaicism of α3-NKA expression, we show that all lumbar motor neurons express α3-NKA. We present an alternative to this hypothesis, showing that usAHPs can be masked by competing conductances. Finally, we show that the post-discharge activity of a neuron can be modulated by extrinsic and intrinsic modulators to enhance or unmask certain post-discharge activity subtypes.
2022-11-29T00:00:00ZSorrell, Francesca LeighThe sodium-potassium pump (NKA) is a ubiquitously expressed membrane protein. Mammalian neurons express two isoforms of the NKA’s catalytic α-subunit, the ubiquitous α1, and the neuron-specific α3. Mutations in the α3-NKA encoding protein ATP1A3 result in a spectrum of neurological disorders with pronounced motor deficits, including Rapid-Onset Dystonia Parkinsonism (RDP). The NKA has also been shown to facilitate activity-dependent changes in spinal motor networks via an ultra-slow afterhyperpolarisation (usAHP) which is thought to be an α3-NKA mediated current.
First, we provide a comprehensive characterisation of a novel mouse model of RDP harbouring the T613M mutation of ATP1A3 most commonly found in patients. We show that T613M animals are hyperactive and hyperambulatory. We show involvement of spinal motor circuit pathology in this behaviour via a complete lack of usAHPs in T613M-affected motor neurons, and a reduced capacity for isolated spinal cords to regulate rhythmic motor output in response to large increases of intracellular sodium. We show that this deficiency is likely caused by a reduced capacity for T613M-affected α3-NKA to extrude sodium and therefore maintain sodium homeostasis.
Next, we characterised post-discharge activity more generally in motor neurons from wildtype mice. We show that usAHPs are more commonly observed in the second postnatal week which may be due to an upregulation of α3-NKA protein expression in motor neurons alongside the development of weight-bearing locomotion. While the heterogenous distribution of usAHPs amongst populations of neurons was previously thought to be due to mosaicism of α3-NKA expression, we show that all lumbar motor neurons express α3-NKA. We present an alternative to this hypothesis, showing that usAHPs can be masked by competing conductances. Finally, we show that the post-discharge activity of a neuron can be modulated by extrinsic and intrinsic modulators to enhance or unmask certain post-discharge activity subtypes.Decision-making, environmental enrichment and the mesolimbic dopamine system in adult and aged ratsLi, Yunkaihttps://hdl.handle.net/10023/270742024-01-06T03:02:25Z2023-06-15T00:00:00ZThe dopaminergic system plays a crucial role in learning, reward-processing, motivation, motor control and attention. The population of midbrain dopamine neurons projects extensively to many areas of the brain. This system is maintained in a homeostatic way, and it can self-regulate to maintain behavioural function in extreme cases such as Parkinson’s disease. However, Huttunen (2016) discovered a significant correlation between midbrain dopamine neuron number in male rats and their behavioural performances in a gambling task. It was unexpected that such non-clinical variation in dopamine neuron number can lead to differences in observable behaviours. Our project aims to investigate the link between dopamine structure and function in risk decision-making, and to explore possible factors that can manipulate the brain and behaviour. Chapter 1 reviewed the dopaminergic system and its adaptive role in conditions such as environmental enrichment and stress. Chapter 2 described the experiment using a modified risk task which failed to replicate the original results from Huttunen (2016). Chapter 3 examined the possible sex difference in the brain of behaviour of rats. Chapter 4 and 5 explored factors that can influence this dopamine-loss-stay relationship, including environmental enrichment and neurogenesis. We demonstrated that dopamine-expressing neurons in the rat midbrain may underlie loss-stay behaviours, which may reflect the animals’ risk-attitude. Moreover, the correlation was significant only when the age of the animal was considered. Therefore, this correlation may be a result of aging, or the compensatory mechanisms that often accompany ageing. Future research may shed light on possible treatment and interventions for neural decline in ageing and other clinical conditions.
2023-06-15T00:00:00ZLi, YunkaiThe dopaminergic system plays a crucial role in learning, reward-processing, motivation, motor control and attention. The population of midbrain dopamine neurons projects extensively to many areas of the brain. This system is maintained in a homeostatic way, and it can self-regulate to maintain behavioural function in extreme cases such as Parkinson’s disease. However, Huttunen (2016) discovered a significant correlation between midbrain dopamine neuron number in male rats and their behavioural performances in a gambling task. It was unexpected that such non-clinical variation in dopamine neuron number can lead to differences in observable behaviours. Our project aims to investigate the link between dopamine structure and function in risk decision-making, and to explore possible factors that can manipulate the brain and behaviour. Chapter 1 reviewed the dopaminergic system and its adaptive role in conditions such as environmental enrichment and stress. Chapter 2 described the experiment using a modified risk task which failed to replicate the original results from Huttunen (2016). Chapter 3 examined the possible sex difference in the brain of behaviour of rats. Chapter 4 and 5 explored factors that can influence this dopamine-loss-stay relationship, including environmental enrichment and neurogenesis. We demonstrated that dopamine-expressing neurons in the rat midbrain may underlie loss-stay behaviours, which may reflect the animals’ risk-attitude. Moreover, the correlation was significant only when the age of the animal was considered. Therefore, this correlation may be a result of aging, or the compensatory mechanisms that often accompany ageing. Future research may shed light on possible treatment and interventions for neural decline in ageing and other clinical conditions.The ontogeny of pant hoot vocalisations and social awareness in wild chimpanzeesSoldati, Adrianhttps://hdl.handle.net/10023/270662023-04-28T21:57:06Z2023-06-15T00:00:00ZWhile some scholars have regarded primate vocal communication as innate, inflexible, and insensitive to the context, recent advances suggest instead that vocal behaviours can be flexible, insofar as they are affected by individual and situational factors, notably the social context. However, whether the same is true for the acquisition of communicative capacities remains largely unknown, particularly in great apes. In my thesis, I address this by examining the ontogeny of vocal behaviours in the pant hoots of immature chimpanzees (Pan troglodytes schweinfurthii) of the Budongo Forest, Uganda. Furthermore, I investigate audience effects on pant hoot sequences used during displays to determine the extent to which these vocal structures are flexibly modulated depending on the social environment.
Pant hoots are a multi-phase vocal sequence typically used to maintain contact and coordinate movements between individuals and groups over long distances. The question of how this complex and flexible vocal signal develops is key for a better understanding of how chimpanzees navigate dynamic social interactions in fission-fusion societies from both an ontogenetic and a comparative perspective.
Results from my thesis show that chimpanzees produced rudimentary pant hoot sequences since birth, suggesting that vocal repertoires are largely innate. However, these sequences presented some structural and acoustic differences when compared to those of older individuals, suggesting they also undergo ontogenetic changes. In addition, the vocal usage and responses to pant hoots in immature chimpanzees was enhanced by greater vocal and social exposure to key group members, such as the mother and adult males, when compared to the development of less gregarious immature individuals. Finally, social context modulated the use of pant hoot phases during vocal displays, likely enhancing the communicative capacities of a species with limited vocal production learning and relatively small vocal repertoire. Taken together, findings from my thesis suggest that the ontogeny of complex chimpanzee vocalisations is socially mediated and that chimpanzee vocal communication is flexibly adjusted depending on the social environment.
2023-06-15T00:00:00ZSoldati, AdrianWhile some scholars have regarded primate vocal communication as innate, inflexible, and insensitive to the context, recent advances suggest instead that vocal behaviours can be flexible, insofar as they are affected by individual and situational factors, notably the social context. However, whether the same is true for the acquisition of communicative capacities remains largely unknown, particularly in great apes. In my thesis, I address this by examining the ontogeny of vocal behaviours in the pant hoots of immature chimpanzees (Pan troglodytes schweinfurthii) of the Budongo Forest, Uganda. Furthermore, I investigate audience effects on pant hoot sequences used during displays to determine the extent to which these vocal structures are flexibly modulated depending on the social environment.
Pant hoots are a multi-phase vocal sequence typically used to maintain contact and coordinate movements between individuals and groups over long distances. The question of how this complex and flexible vocal signal develops is key for a better understanding of how chimpanzees navigate dynamic social interactions in fission-fusion societies from both an ontogenetic and a comparative perspective.
Results from my thesis show that chimpanzees produced rudimentary pant hoot sequences since birth, suggesting that vocal repertoires are largely innate. However, these sequences presented some structural and acoustic differences when compared to those of older individuals, suggesting they also undergo ontogenetic changes. In addition, the vocal usage and responses to pant hoots in immature chimpanzees was enhanced by greater vocal and social exposure to key group members, such as the mother and adult males, when compared to the development of less gregarious immature individuals. Finally, social context modulated the use of pant hoot phases during vocal displays, likely enhancing the communicative capacities of a species with limited vocal production learning and relatively small vocal repertoire. Taken together, findings from my thesis suggest that the ontogeny of complex chimpanzee vocalisations is socially mediated and that chimpanzee vocal communication is flexibly adjusted depending on the social environment.The effect of self-correction on implicit and explicit representational change in children’s problem-solvingYuniarto, Laras Sekarrinihttps://hdl.handle.net/10023/269922023-04-29T22:02:32Z2022-11-29T00:00:00ZChildren’s understanding of problems becomes more abstract and sophisticated as they gain experience with solving them. This thesis uses the framework of the Representational Redescription Model (RRM; Karmiloff-Smith, 1992) to capture how children’s representations progress from implicit to explicit through a process of representational redescription, which progressively re-represents information in the mind to make it more conscious, manipulable, and accessible to verbal and gestural report. In particular, I focus on the RRM’s claim that redescription is triggered through a period of behavioural success without explicit understanding. The lack of opportunities to achieve such implicit, procedural success may explain why young children fail to solve causal problems that they might otherwise understand (e.g., trap-tasks). The RRM suggests that modifying such tasks to facilitate behavioural mastery, such as by incorporating correction of one’s mistakes, might improve performance and understanding amongst young children.
The empirical studies of this thesis investigated the role of self-correction on problem-solving in 2.5- and 3-year-old children. Using a physical trap-task, Study 1 showed that self-corrective practice (compared to non-corrective practice) led to significant improvements in performance when the role of the trap was reversed. Study 2 extended these findings to a digital trap-task, finding that such improvement was not unique to self-correction but could be elicited through extra remedial trials as well. In Study 1, self-correction benefited all ages, while in Study 2, only older children benefited. However, in both studies, children could explain the task appropriately for their age regardless of their performance or their practice condition. I discuss my interpretation of these findings as possible evidence of partial representational redescription, and as evidence of a more complex relationship between behaviour and explanation than predicted by the RRM, with implications for the model’s future use as well as for our understanding of representational change during problem-solving.
2022-11-29T00:00:00ZYuniarto, Laras SekarriniChildren’s understanding of problems becomes more abstract and sophisticated as they gain experience with solving them. This thesis uses the framework of the Representational Redescription Model (RRM; Karmiloff-Smith, 1992) to capture how children’s representations progress from implicit to explicit through a process of representational redescription, which progressively re-represents information in the mind to make it more conscious, manipulable, and accessible to verbal and gestural report. In particular, I focus on the RRM’s claim that redescription is triggered through a period of behavioural success without explicit understanding. The lack of opportunities to achieve such implicit, procedural success may explain why young children fail to solve causal problems that they might otherwise understand (e.g., trap-tasks). The RRM suggests that modifying such tasks to facilitate behavioural mastery, such as by incorporating correction of one’s mistakes, might improve performance and understanding amongst young children.
The empirical studies of this thesis investigated the role of self-correction on problem-solving in 2.5- and 3-year-old children. Using a physical trap-task, Study 1 showed that self-corrective practice (compared to non-corrective practice) led to significant improvements in performance when the role of the trap was reversed. Study 2 extended these findings to a digital trap-task, finding that such improvement was not unique to self-correction but could be elicited through extra remedial trials as well. In Study 1, self-correction benefited all ages, while in Study 2, only older children benefited. However, in both studies, children could explain the task appropriately for their age regardless of their performance or their practice condition. I discuss my interpretation of these findings as possible evidence of partial representational redescription, and as evidence of a more complex relationship between behaviour and explanation than predicted by the RRM, with implications for the model’s future use as well as for our understanding of representational change during problem-solving.Investigating astrocyte-synapse interactions in amyotrophic lateral sclerosisBonthron, Calumhttps://hdl.handle.net/10023/269802024-03-12T10:29:57Z2022-11-29T00:00:00ZAmyotrophic Lateral Sclerosis (ALS) is fatal neurodegenerative condition characterised by the loss of upper and lower motor neurons (MNs). Given that synapses and astrocytes regularly interact in the healthy spinal cord, and that pathology involving both has been reported in ALS, we posited that synaptic and astrocytic mechanisms may be intrinsically linked. One essential astrocytic function is synaptogenesis. Hyperexcitability of pre-MN networks has been observed in ALS, with a possible basis of this change being perturbed astrocytic synaptogenesis causing an early non-cell autonomous shift in excitatory : inhibitory (E:I) synaptic ratios. To look at this, we developed and validated a novel postnatal primary co-culture system of spinal astrocytes and neurons. These cultures were generated using multiple ALS mouse models bred with animals expressing a GFP tag on the postsynaptic density protein PSD95, with immunocytochemical targeting of presynaptic protein synapsin, and inhibitory postsynaptic protein gephyrin. We found that no combination of neuron or astrocyte genotypes altered E:I ratios in both SOD1ᴳ⁹³ᴬ and C9BAC500 co-cultures. This lack of E:I ratio change was also seen in SOD1ᴳ⁹³ᴬ spinal cords after the peak of postnatal spinal synaptogenesis, and in human ALS patient iPSC-derived MN / astrocyte cultures. Post-synapse formation, however, astrocytes also interact with mature synapses at structures called tripartite synapses. As dysfunction at tripartite synapses has previously been reported, we investigated these structures throughout disease progression in SOD1ᴳ⁹³ᴬ PSD95-eGFP animals. Using multiple markers for perisynaptic astrocytic processes, the motile elements that envelop synapses, we observed consistent loss of tripartite synapses at the early symptomatic stage of 16W. Non-tripartite synapses, however, remained similar in number to controls. This was replicated in human ALS post-mortem tissue. We therefore conclude that although we find no evidence that astrocytes are driving early E:I ratio shifts, we reveal that later in pathogenesis tripartite synapses appear to be a vulnerable fulcrum of disease in ALS.
2022-11-29T00:00:00ZBonthron, CalumAmyotrophic Lateral Sclerosis (ALS) is fatal neurodegenerative condition characterised by the loss of upper and lower motor neurons (MNs). Given that synapses and astrocytes regularly interact in the healthy spinal cord, and that pathology involving both has been reported in ALS, we posited that synaptic and astrocytic mechanisms may be intrinsically linked. One essential astrocytic function is synaptogenesis. Hyperexcitability of pre-MN networks has been observed in ALS, with a possible basis of this change being perturbed astrocytic synaptogenesis causing an early non-cell autonomous shift in excitatory : inhibitory (E:I) synaptic ratios. To look at this, we developed and validated a novel postnatal primary co-culture system of spinal astrocytes and neurons. These cultures were generated using multiple ALS mouse models bred with animals expressing a GFP tag on the postsynaptic density protein PSD95, with immunocytochemical targeting of presynaptic protein synapsin, and inhibitory postsynaptic protein gephyrin. We found that no combination of neuron or astrocyte genotypes altered E:I ratios in both SOD1ᴳ⁹³ᴬ and C9BAC500 co-cultures. This lack of E:I ratio change was also seen in SOD1ᴳ⁹³ᴬ spinal cords after the peak of postnatal spinal synaptogenesis, and in human ALS patient iPSC-derived MN / astrocyte cultures. Post-synapse formation, however, astrocytes also interact with mature synapses at structures called tripartite synapses. As dysfunction at tripartite synapses has previously been reported, we investigated these structures throughout disease progression in SOD1ᴳ⁹³ᴬ PSD95-eGFP animals. Using multiple markers for perisynaptic astrocytic processes, the motile elements that envelop synapses, we observed consistent loss of tripartite synapses at the early symptomatic stage of 16W. Non-tripartite synapses, however, remained similar in number to controls. This was replicated in human ALS post-mortem tissue. We therefore conclude that although we find no evidence that astrocytes are driving early E:I ratio shifts, we reveal that later in pathogenesis tripartite synapses appear to be a vulnerable fulcrum of disease in ALS.Investigating the role of memory errors and memory expectation conflict in the experience and reporting of déjà vuAitken, Courtney Bernadette Annhttps://hdl.handle.net/10023/261372024-01-17T12:03:28Z2022-11-29T00:00:00ZAbstract redacted
2022-11-29T00:00:00ZAitken, Courtney Bernadette AnnAbstract redactedTitle redactedDuncan, Stephenhttps://hdl.handle.net/10023/259062022-08-30T02:08:07Z2022-11-29T00:00:00Z2022-11-29T00:00:00ZDuncan, StephenThe influence of body composition on social judgementsLei, Xuehttps://hdl.handle.net/10023/236952021-08-09T11:56:11Z2020-07-31T00:00:00ZBody Mass Index (BMI; weight scaled by squared height) is a crucial determinant of
physical attractiveness, potentially because BMI signals mate value. Yet, BMI does not
contain information about body composition, namely fat and muscle, which might be a better
indication of mate value. The current thesis explored the potential influence of body
composition on attractiveness and other social judgements.
Study 1 investigated the influence of facial correlates of body composition on
perceived male facial masculinity. Facial correlates of muscle consistently enhanced facial
masculinity, whereas facial correlates of fat increased masculinity perception in underweight
to normal-weight men only.
Study 2 investigated women’s preferences for facial correlates of body composition in
short- and long-term relationships. Women have stronger preferences for facial correlates of
muscle in short- compared to long-term relationships, while no discrepancy was observed in
preferences for facial correlates of fat.
Study 3 investigated how body composition influences health and kindness
judgements from male faces. Perceived health increased with increasing fat and muscle from
underweight to normal-weight men but decreased with further increases in fat and muscle.
Increase in facial correlates of muscle dramatically diminished perceived kindness, but facial
correlates of fat showed a slight detrimental impact on perceived kindness.
Study 4 investigated whether men and women have accurate perceptions of opposite-
sex preferences for body shape. Women exaggerated the thinness that men prefer; men
exaggerated the heaviness and muscularity that women prefer. Moreover, these
misperceptions were larger for short- compared to long-term relationships.
The thesis demonstrates the distinct effects of fat and muscle on social judgements
and reveals that men and women misperceive opposite-sex preferences. These findings point
out the importance of distinguishing body composition of studies of body size.
2020-07-31T00:00:00ZLei, XueBody Mass Index (BMI; weight scaled by squared height) is a crucial determinant of
physical attractiveness, potentially because BMI signals mate value. Yet, BMI does not
contain information about body composition, namely fat and muscle, which might be a better
indication of mate value. The current thesis explored the potential influence of body
composition on attractiveness and other social judgements.
Study 1 investigated the influence of facial correlates of body composition on
perceived male facial masculinity. Facial correlates of muscle consistently enhanced facial
masculinity, whereas facial correlates of fat increased masculinity perception in underweight
to normal-weight men only.
Study 2 investigated women’s preferences for facial correlates of body composition in
short- and long-term relationships. Women have stronger preferences for facial correlates of
muscle in short- compared to long-term relationships, while no discrepancy was observed in
preferences for facial correlates of fat.
Study 3 investigated how body composition influences health and kindness
judgements from male faces. Perceived health increased with increasing fat and muscle from
underweight to normal-weight men but decreased with further increases in fat and muscle.
Increase in facial correlates of muscle dramatically diminished perceived kindness, but facial
correlates of fat showed a slight detrimental impact on perceived kindness.
Study 4 investigated whether men and women have accurate perceptions of opposite-
sex preferences for body shape. Women exaggerated the thinness that men prefer; men
exaggerated the heaviness and muscularity that women prefer. Moreover, these
misperceptions were larger for short- compared to long-term relationships.
The thesis demonstrates the distinct effects of fat and muscle on social judgements
and reveals that men and women misperceive opposite-sex preferences. These findings point
out the importance of distinguishing body composition of studies of body size.Understanding multisensory processing in a wider context using a model-based approachLiu, Yuehttps://hdl.handle.net/10023/236622021-07-28T14:30:40Z2021-07-02T00:00:00ZAn overarching goal of multisensory research is to understand multisensory behaviour in a wider context but still within a unified framework. Modelling has been a useful tool to understand how information from different senses is combined to produce behaviour. For example, different models have been used to understand the improvement in speed or precision of multisensory relative to unisensory decisions (Ernst & Banks, 2002; Raab, 1962). However, these modelling approaches are limited to address a single measure of multisensory decisions, for example, models of speed cannot explain precision and models of precision cannot explain speed. The field is still working towards developing a unified modelling framework that can link the different aspects of multisensory decisions together. In aim of this, I addressed three gaps in research on multisensory decision making, which I believe is essential to address the missing linkage between studies of multisensory behaviour. Firstly, most multisensory modelling work has used an implicit assumption, which states that processing of a unisensory signal and processing of the corresponding unisensory component of a multisensory signals are identical. However, the validity of this assumption, has not been tested. I offered a way to understand this assumption under experimental settings and proved that it is most likely violated. This suggests that studies of multisensory behaviour should rather consider the influence of context in modelling work. Secondly, I addressed that multisensory response at neuronal and behavioural level can be linked. The spatial principle, which is found in neuronal studies, can be mapped to behaviour and accounted for by a race model. Thirdly, I attempt to address the link between speed and precision of multisensory behaviour. In the past, the two have rarely been studied within a unified paradigm. I found that when both measures were required, participants are far from achieving optimality in either speed or precision, and it is possible that they are switching strategies towards favouring one of the measures in such decisions. The race model is a strong candidate to be refined and developed in future research to incorporate more aspects of multisensory decisions, as I have address it is not limited to explain speedup in simple detection task, but also influence of context, space, and precision in more complex experimental tasks.
2021-07-02T00:00:00ZLiu, YueAn overarching goal of multisensory research is to understand multisensory behaviour in a wider context but still within a unified framework. Modelling has been a useful tool to understand how information from different senses is combined to produce behaviour. For example, different models have been used to understand the improvement in speed or precision of multisensory relative to unisensory decisions (Ernst & Banks, 2002; Raab, 1962). However, these modelling approaches are limited to address a single measure of multisensory decisions, for example, models of speed cannot explain precision and models of precision cannot explain speed. The field is still working towards developing a unified modelling framework that can link the different aspects of multisensory decisions together. In aim of this, I addressed three gaps in research on multisensory decision making, which I believe is essential to address the missing linkage between studies of multisensory behaviour. Firstly, most multisensory modelling work has used an implicit assumption, which states that processing of a unisensory signal and processing of the corresponding unisensory component of a multisensory signals are identical. However, the validity of this assumption, has not been tested. I offered a way to understand this assumption under experimental settings and proved that it is most likely violated. This suggests that studies of multisensory behaviour should rather consider the influence of context in modelling work. Secondly, I addressed that multisensory response at neuronal and behavioural level can be linked. The spatial principle, which is found in neuronal studies, can be mapped to behaviour and accounted for by a race model. Thirdly, I attempt to address the link between speed and precision of multisensory behaviour. In the past, the two have rarely been studied within a unified paradigm. I found that when both measures were required, participants are far from achieving optimality in either speed or precision, and it is possible that they are switching strategies towards favouring one of the measures in such decisions. The race model is a strong candidate to be refined and developed in future research to incorporate more aspects of multisensory decisions, as I have address it is not limited to explain speedup in simple detection task, but also influence of context, space, and precision in more complex experimental tasks.Title redactedde las Heras Martínez, Áfricahttps://hdl.handle.net/10023/235562023-04-06T16:00:16Z2021-07-02T00:00:00Z2021-07-02T00:00:00Zde las Heras Martínez, ÁfricaAgeing biomarkers in the brain : exploring stress effects in traditional and non-traditional model systemsMorisaki, Mizukihttps://hdl.handle.net/10023/235432021-08-10T13:11:27Z2021-07-02T00:00:00ZAgeing is a complex mechanism influenced by multiple factors. Stress, which could affect ageing, is mainly controlled by the hypothalamus-pituitary-adrenal (HPA)-axis and subsequent glucocorticoid (GC) release. Increases in GCs also induce long-lasting developmental changes in the organism (i.e. GC developmental programming), which may, in turn, affect brain ageing processes.
This thesis aimed to determine the effects of stress on the brain by examining ageing biomarkers using both in-vitro and in-vivo approaches. In Chapter 2, the effects of stress biomarkers (GCs and alpha-amylase) were explored at cellular level, using HT22 (murine hippocampal neuronal cells). Within physiological concentrations, cortisol, but not corticosterone, showed a potential protective effect. Moreover, alpha-amylase protected cells against additional stressors, suggesting that increased stress biomarkers maintained cellular viability, instead of affecting senescent phenotypes.
In Chapter 3, the typical mammalian brain ageing phenotypes were characterised in Japanese quail (Coturnix japonica) prior to investigating prenatal GC programming. Increased oxidative damage accumulation and changes in adult neurogenesis were found. Contrastingly, neuronal loss and increased white matter lesions were not observed.
Chapter 4 investigated the prenatal GC programming effect in juvenile quail brains. Prenatal stress reduced glucocorticoid receptor expression in the amygdala and nidopallium, indicating prenatal GC programming; however, oxidative damage accumulation was unaffected.
In Chapter 5, the prenatal GC programming effect was examined on both the stress response and neurogenesis in adult quails. Prenatal stress resulted in higher peak stress responses and increased neurogenesis, suggesting that it maintained high neuronal plasticity rather than enhancing typical ageing phenotypes.
In conclusion, although ageing phenotypes are not necessarily conserved, comparative animal models can aid the investigation of human brain ageing. Stress may indirectly affect ageing via other systems. Therefore, investigating brain ageing at the system level should be considered as an alternative to focusing on single biomarkers in future.
2021-07-02T00:00:00ZMorisaki, MizukiAgeing is a complex mechanism influenced by multiple factors. Stress, which could affect ageing, is mainly controlled by the hypothalamus-pituitary-adrenal (HPA)-axis and subsequent glucocorticoid (GC) release. Increases in GCs also induce long-lasting developmental changes in the organism (i.e. GC developmental programming), which may, in turn, affect brain ageing processes.
This thesis aimed to determine the effects of stress on the brain by examining ageing biomarkers using both in-vitro and in-vivo approaches. In Chapter 2, the effects of stress biomarkers (GCs and alpha-amylase) were explored at cellular level, using HT22 (murine hippocampal neuronal cells). Within physiological concentrations, cortisol, but not corticosterone, showed a potential protective effect. Moreover, alpha-amylase protected cells against additional stressors, suggesting that increased stress biomarkers maintained cellular viability, instead of affecting senescent phenotypes.
In Chapter 3, the typical mammalian brain ageing phenotypes were characterised in Japanese quail (Coturnix japonica) prior to investigating prenatal GC programming. Increased oxidative damage accumulation and changes in adult neurogenesis were found. Contrastingly, neuronal loss and increased white matter lesions were not observed.
Chapter 4 investigated the prenatal GC programming effect in juvenile quail brains. Prenatal stress reduced glucocorticoid receptor expression in the amygdala and nidopallium, indicating prenatal GC programming; however, oxidative damage accumulation was unaffected.
In Chapter 5, the prenatal GC programming effect was examined on both the stress response and neurogenesis in adult quails. Prenatal stress resulted in higher peak stress responses and increased neurogenesis, suggesting that it maintained high neuronal plasticity rather than enhancing typical ageing phenotypes.
In conclusion, although ageing phenotypes are not necessarily conserved, comparative animal models can aid the investigation of human brain ageing. Stress may indirectly affect ageing via other systems. Therefore, investigating brain ageing at the system level should be considered as an alternative to focusing on single biomarkers in future.Investigating the neuroprotective effects of leptin and leptin fragment on mitochondrial morphology, function and survival signalling in neurodegenerative modelsCheng, Yinghttps://hdl.handle.net/10023/235322021-07-20T13:10:03Z2021-07-02T00:00:00ZMitochondrial dysfunction has a recognized role in the pathophysiology of neurodegeneration,
including ischemic stroke and Alzheimer’s disease (AD). Compelling evidence shows that leptin
prevents neuronal apoptosis and enhances cognition in AD models, and a bioactive fragment,
leptin₁₁₆₋₁₃₀, mirrors the neuroprotective actions of leptin. However, their effects with relation to
mitochondrial function in neurodegeneration and the receptor binding of leptin₁₁₆₋₁₃₀ remain
largely unknown.
Based on a combined glucose-serum deprivation (CGSD) model of ischaemic stroke in human
SH-SY5Y cells and an Aβ₄₂-treatment model of AD in mouse hippocampal HT-22 cells, it is
shown within the thesis that leptin alleviates excessive mitochondrial fragmentation by inhibiting
fission protein Fis1 and increasing fusion protein Mfn2. Leptin improves mitochondrial function
through enhancing mitochondrial membrane potential and inhibiting monoamine oxidase (MAO)
that is involved in the production of reactive oxygen species (ROS). Furthermore, it is found that
17β-HSD10 is a molecular target of leptin in mitochondria by showing that leptin inhibits both
the expression and activity of 17β-HSD10. Leptin and the inhibition of 17β-HSD10 rebalance
energy metabolism through improving neuronal glucose uptake. Notably, leptin-mediated
inhibition of 17β-HSD10 is associated with better episodic memory. Both leptin and leptin116-130
decrease ROS generation and promote neuron survival in oxidative stress-induced wildtype
neurons, whereas only leptin₁₁₆₋₁₃₀ retains its neuroprotective effects in leptin receptor (ObR)
knockdown neurons, suggesting that actions of leptin₁₁₆₋₁₃₀ are in a ObR-independent manner.
In conclusion, leptin’s established neuroprotective actions may, at least in part, be facilitated
through regulating mitochondrial function and morphology. Inhibited mitochondrial 17β-HSD10
contributes to leptin’s procognitive role. The receptor binding of leptin₁₁₆₋₁₃₀ is not restricted to
the ObR activation, suggesting the potential application of leptin₁₁₆₋₁₃₀ in leptin resistant
individuals. These findings provide more robust evidence to support that leptin system is a
potential therapeutic target in AD.
2021-07-02T00:00:00ZCheng, YingMitochondrial dysfunction has a recognized role in the pathophysiology of neurodegeneration,
including ischemic stroke and Alzheimer’s disease (AD). Compelling evidence shows that leptin
prevents neuronal apoptosis and enhances cognition in AD models, and a bioactive fragment,
leptin₁₁₆₋₁₃₀, mirrors the neuroprotective actions of leptin. However, their effects with relation to
mitochondrial function in neurodegeneration and the receptor binding of leptin₁₁₆₋₁₃₀ remain
largely unknown.
Based on a combined glucose-serum deprivation (CGSD) model of ischaemic stroke in human
SH-SY5Y cells and an Aβ₄₂-treatment model of AD in mouse hippocampal HT-22 cells, it is
shown within the thesis that leptin alleviates excessive mitochondrial fragmentation by inhibiting
fission protein Fis1 and increasing fusion protein Mfn2. Leptin improves mitochondrial function
through enhancing mitochondrial membrane potential and inhibiting monoamine oxidase (MAO)
that is involved in the production of reactive oxygen species (ROS). Furthermore, it is found that
17β-HSD10 is a molecular target of leptin in mitochondria by showing that leptin inhibits both
the expression and activity of 17β-HSD10. Leptin and the inhibition of 17β-HSD10 rebalance
energy metabolism through improving neuronal glucose uptake. Notably, leptin-mediated
inhibition of 17β-HSD10 is associated with better episodic memory. Both leptin and leptin116-130
decrease ROS generation and promote neuron survival in oxidative stress-induced wildtype
neurons, whereas only leptin₁₁₆₋₁₃₀ retains its neuroprotective effects in leptin receptor (ObR)
knockdown neurons, suggesting that actions of leptin₁₁₆₋₁₃₀ are in a ObR-independent manner.
In conclusion, leptin’s established neuroprotective actions may, at least in part, be facilitated
through regulating mitochondrial function and morphology. Inhibited mitochondrial 17β-HSD10
contributes to leptin’s procognitive role. The receptor binding of leptin₁₁₆₋₁₃₀ is not restricted to
the ObR activation, suggesting the potential application of leptin₁₁₆₋₁₃₀ in leptin resistant
individuals. These findings provide more robust evidence to support that leptin system is a
potential therapeutic target in AD.Title redactedIsham, Aleksandra Eriksenhttps://hdl.handle.net/10023/234762021-07-20T14:20:25Z2021-07-02T00:00:00Z2021-07-02T00:00:00ZIsham, Aleksandra EriksenDomain-specialised and domain-general neurocognitive substrates in language and music domains : contributions from ERP correlates of expectancy violationsMoodie, Joanna Elizabethhttps://hdl.handle.net/10023/234622023-09-20T02:05:41Z2021-07-02T00:00:00ZThis thesis contributes to the interdisciplinary debate about the extent of shared and separable neurocognitive mechanisms between language and music processing. To achieve this, ERP (event-related potential) correlates of expectancy violations for major processes in each domain were investigated. The results of Chapter 3 support the distinctness of ERP effects elicited by semantic, grammar and harmonic expectancy violations (a centroparietal N400, central P600 and frontal P300, respectively). These findings support the hypothesis that these processes rely on separable neurocognitive substrates. In Chapter 4, meter violations elicit an N1 effect in the music domain, but the evidence for an N1 effect in the language domain was inconclusive. There was a P2 effect in both language and music domains, providing novel support for the hypothesis that some substrates involved in meter processing are domain-general. Finally, in Chapter 5, meter violations were presented simultaneously with semantic, grammar and harmonic violations. All aforementioned ERP effects were replicated. Crucially, there were no interactions in any ERP effects, signalling that their associated processes rely on distinct substrates. Overall, this thesis provides valuable contributions to the literature, indicating that at least some neurocognitive substrates involved in semantic, grammar and harmony processing are domain-specialised, while those involved in meter processing could be domain-general.
2021-07-02T00:00:00ZMoodie, Joanna ElizabethThis thesis contributes to the interdisciplinary debate about the extent of shared and separable neurocognitive mechanisms between language and music processing. To achieve this, ERP (event-related potential) correlates of expectancy violations for major processes in each domain were investigated. The results of Chapter 3 support the distinctness of ERP effects elicited by semantic, grammar and harmonic expectancy violations (a centroparietal N400, central P600 and frontal P300, respectively). These findings support the hypothesis that these processes rely on separable neurocognitive substrates. In Chapter 4, meter violations elicit an N1 effect in the music domain, but the evidence for an N1 effect in the language domain was inconclusive. There was a P2 effect in both language and music domains, providing novel support for the hypothesis that some substrates involved in meter processing are domain-general. Finally, in Chapter 5, meter violations were presented simultaneously with semantic, grammar and harmonic violations. All aforementioned ERP effects were replicated. Crucially, there were no interactions in any ERP effects, signalling that their associated processes rely on distinct substrates. Overall, this thesis provides valuable contributions to the literature, indicating that at least some neurocognitive substrates involved in semantic, grammar and harmony processing are domain-specialised, while those involved in meter processing could be domain-general.Metacognitive calibration in exercise : an examination using running and high-intensity functional movement exerciseLiverakos, Konstantinoshttps://hdl.handle.net/10023/234602021-07-21T13:57:57Z2021-07-02T00:00:00ZIn the present thesis, I examined exercise calibration using running and high-intensity functional movement exercise (HIFME). In doing so, I analysed and presented results from eight studies across Chapters 2, 3, 4, and 5. In Chapters 2 and 3, I explored the extent to which demographic factors (e.g. expertise, experience, age, and gender) are effective in informing us about running and HIFME calibration. Studies 1 and 2 demonstrated that such factors do exhibit associations with running calibration, though the relatively minor strength and inconsistency of these associations also indicate that we should not overestimate the factors’ contributions. Study 3 found a positive role of having a HIFME background in HIFME calibration, but other demographic factors did not exhibit associations with it. Overall, results from Chapters 2 and 3 highlighted the importance of considering demographic factors when assessing athlete calibration. However, they also highlighted the importance of understanding their limitations when doing so. In Chapter 4, I examined whether we can use self-reports of exercise metacognition and cognitive calibration to predict running and HIFME calibration. There was no significant association between any of these measures and exercise calibration in Studies 4, 5, and 6, suggesting that metacognition self-reports and calibration from other modalities are not reliable predictors of exercise calibration. In Chapter 5, I tested whether a minimal metacognitive intervention in the form of prediction guidance would lead to improved exercise calibration when participants received strategic, as opposed to impulsive, instructions. Findings from Studies 7 and 8 illustrated that strategic predictions facilitated prediction precision compared to impulsive predictions, though their effects on bias appeared to be less consistent and more dependent upon instructions. In Chapter 6, I discussed the general implications of the present thesis, and proposed ways in which future research can further explore the field of exercise calibration.
2021-07-02T00:00:00ZLiverakos, KonstantinosIn the present thesis, I examined exercise calibration using running and high-intensity functional movement exercise (HIFME). In doing so, I analysed and presented results from eight studies across Chapters 2, 3, 4, and 5. In Chapters 2 and 3, I explored the extent to which demographic factors (e.g. expertise, experience, age, and gender) are effective in informing us about running and HIFME calibration. Studies 1 and 2 demonstrated that such factors do exhibit associations with running calibration, though the relatively minor strength and inconsistency of these associations also indicate that we should not overestimate the factors’ contributions. Study 3 found a positive role of having a HIFME background in HIFME calibration, but other demographic factors did not exhibit associations with it. Overall, results from Chapters 2 and 3 highlighted the importance of considering demographic factors when assessing athlete calibration. However, they also highlighted the importance of understanding their limitations when doing so. In Chapter 4, I examined whether we can use self-reports of exercise metacognition and cognitive calibration to predict running and HIFME calibration. There was no significant association between any of these measures and exercise calibration in Studies 4, 5, and 6, suggesting that metacognition self-reports and calibration from other modalities are not reliable predictors of exercise calibration. In Chapter 5, I tested whether a minimal metacognitive intervention in the form of prediction guidance would lead to improved exercise calibration when participants received strategic, as opposed to impulsive, instructions. Findings from Studies 7 and 8 illustrated that strategic predictions facilitated prediction precision compared to impulsive predictions, though their effects on bias appeared to be less consistent and more dependent upon instructions. In Chapter 6, I discussed the general implications of the present thesis, and proposed ways in which future research can further explore the field of exercise calibration.Investigating the relationship between visual and contextual cues in visual word recognitionMurphy, Ailis F.https://hdl.handle.net/10023/218072021-10-21T10:25:52Z2000-01-01T00:00:00ZA well documented finding in the word recognition literature is that accurate report of a word is facilitated when it is embedded in a meaningful and grammatical sentence. Previous researchers have accounted for the influence of context on word recognition in two ways. From a modular perspective, word recognition is unaffected by sentence structure or content, the effects arise from post-perceptual decisions and from spreading activation between associated words within the lexicon. In contrast, from an interactive perspective, word recognition receives direct facilitation from sentence content and structure either by pre-activating or constraining activation to likely word candidates. The experiments reported in this thesis investigate the role of sentence contexts in visual word recognition in order to distinguish between modular and interactive perspectives. This was done by contrasting the effects on target word perception produced by legal, word replacement, nonword and transposed sentence contexts when the effects of semantic word association were suppressed. Performance was measured using the alternate forced choice Reicher-Wheeler Task to suppress the influences of sophisticated guesswork. Low constraint legal sentences produced superior accuracy than control contexts. High constraint legal sentences containing predictable and unpredictable target words but little word association produced superior performance for predictable targets over all other context conditions. When predictability was made more salient by increasing the amount of legal sentences in the experimental session there was no reliable effect of context. However, predictable targets were reported more accurately and unpredictable targets less accurately in legal and transposed contexts than in control conditions. Blurred target words in low and high constraint sentences produced legal sentence advantages. These findings suggest that legal sentence contexts do influence actual word perception at low relatedness proportions but not at high relatedness proportions. The findings favour the dual route multistage activation model of context effects on word recognition.
2000-01-01T00:00:00ZMurphy, Ailis F.A well documented finding in the word recognition literature is that accurate report of a word is facilitated when it is embedded in a meaningful and grammatical sentence. Previous researchers have accounted for the influence of context on word recognition in two ways. From a modular perspective, word recognition is unaffected by sentence structure or content, the effects arise from post-perceptual decisions and from spreading activation between associated words within the lexicon. In contrast, from an interactive perspective, word recognition receives direct facilitation from sentence content and structure either by pre-activating or constraining activation to likely word candidates. The experiments reported in this thesis investigate the role of sentence contexts in visual word recognition in order to distinguish between modular and interactive perspectives. This was done by contrasting the effects on target word perception produced by legal, word replacement, nonword and transposed sentence contexts when the effects of semantic word association were suppressed. Performance was measured using the alternate forced choice Reicher-Wheeler Task to suppress the influences of sophisticated guesswork. Low constraint legal sentences produced superior accuracy than control contexts. High constraint legal sentences containing predictable and unpredictable target words but little word association produced superior performance for predictable targets over all other context conditions. When predictability was made more salient by increasing the amount of legal sentences in the experimental session there was no reliable effect of context. However, predictable targets were reported more accurately and unpredictable targets less accurately in legal and transposed contexts than in control conditions. Blurred target words in low and high constraint sentences produced legal sentence advantages. These findings suggest that legal sentence contexts do influence actual word perception at low relatedness proportions but not at high relatedness proportions. The findings favour the dual route multistage activation model of context effects on word recognition.Probing the interconnectivity of rhythm generating modules in Drosophila melanogaster larvaeJonaitis, Juliushttps://hdl.handle.net/10023/216062024-01-29T12:11:19Z2020-07-31T00:00:00Z2020-07-31T00:00:00ZJonaitis, JuliusThe impact of counter-narratives on inclusive identity and reconciliation support in the context of anti-communist sentiment in IndonesiaThontowi, Haidarhttps://hdl.handle.net/10023/214782021-08-14T14:09:04Z2020-12-01T00:00:00ZPsychologists have argued that counter-narratives play an important role in reconciliation processes. However, limited experimental evidence exists to explain the conditions of when counter-narratives are most effective. This thesis attempts to fill this gap in the literature in the context of Indonesia’s past persecution of communists. Using insights from the political solidarity model (Subasic et al., 2008) and the theory of inclusive victimhood consciousness (Vollhardt, 2013) s a framework, I argue that co-victimization counter-narratives would be more effective in promoting reconciliation. In addition, I reason that a co-victimization counter-narrative would affect reconciliation by increasing participants’ sense of inclusive identity with ex-communists. Accordingly, I conducted four online experiments collecting data from a total of 1,620 Indonesian participants. In study 1, I found that the co-victimization counter-narrative was more effective in promoting reconciliation compared to the control group and that its effect on reconciliation was mediated by inclusive identity. In study 2, I identified political Islam as moderating the influence of the counter-narratives on inclusive identity such that the co-victimization counter-narrative was not effective among participants who highly endorsed political Islam. Study 3 attempted to use norms as a way to increase the strength of the counter-narrative. I found that, as expected, a group relevant norm manipulation showed no additive effect on co-victimization. However, through exploratory analysis, I also found that pairing the counter-narratives with the norm manipulations had significant effects depending on political Islam endorsement levels and perceived descriptive and injunctive norms. Study 4 explored the role of threat in affecting resistance to counter-narratives. The main finding was that manipulations of low threat allowed the counter-narrative to affect inclusive identity among participants who reported low endorsement of political Islam while manipulations of high threat produced an effect of the counter-narrative on inclusive identity among participants who reported high endorsement of political Islam.
2020-12-01T00:00:00ZThontowi, HaidarPsychologists have argued that counter-narratives play an important role in reconciliation processes. However, limited experimental evidence exists to explain the conditions of when counter-narratives are most effective. This thesis attempts to fill this gap in the literature in the context of Indonesia’s past persecution of communists. Using insights from the political solidarity model (Subasic et al., 2008) and the theory of inclusive victimhood consciousness (Vollhardt, 2013) s a framework, I argue that co-victimization counter-narratives would be more effective in promoting reconciliation. In addition, I reason that a co-victimization counter-narrative would affect reconciliation by increasing participants’ sense of inclusive identity with ex-communists. Accordingly, I conducted four online experiments collecting data from a total of 1,620 Indonesian participants. In study 1, I found that the co-victimization counter-narrative was more effective in promoting reconciliation compared to the control group and that its effect on reconciliation was mediated by inclusive identity. In study 2, I identified political Islam as moderating the influence of the counter-narratives on inclusive identity such that the co-victimization counter-narrative was not effective among participants who highly endorsed political Islam. Study 3 attempted to use norms as a way to increase the strength of the counter-narrative. I found that, as expected, a group relevant norm manipulation showed no additive effect on co-victimization. However, through exploratory analysis, I also found that pairing the counter-narratives with the norm manipulations had significant effects depending on political Islam endorsement levels and perceived descriptive and injunctive norms. Study 4 explored the role of threat in affecting resistance to counter-narratives. The main finding was that manipulations of low threat allowed the counter-narrative to affect inclusive identity among participants who reported low endorsement of political Islam while manipulations of high threat produced an effect of the counter-narrative on inclusive identity among participants who reported high endorsement of political Islam.The antecedents, consequences and trajectories of shared identity in emergencies and disastersZhang, Menghttps://hdl.handle.net/10023/214712021-02-23T03:02:40Z2020-12-01T00:00:00ZGroup processes in emergencies and disasters have been studied for decades by psychologists, and they have developed many theories to explain collective behaviours. One of the most recent and reasonable theoretical frameworks is the social identity model. The social identity model posits that it is the shared social identity that underpins various group behaviours, especially solidary behaviours, which were widely observed and reported in previous research. While there was abundant research showing that validated the social identity approach, there were still many questions unanswered. The present research sought to answer three general questions: (1) can the social identity model of collective behaviours in emergencies and disasters be applied in a non-Western background? (2) how does shared identity develop over time? (3) what factors may enhance or undermine the strength of shared identity?
Four studies were designed to answer these questions. Study 1 and study 2 were two field studies adopting an ethnographic approach. They sought to explore the research questions in general, but in two different settings – one about an earthquake in China, and the other about a flood in Ireland. By comparing the results of the two field studies, four factors that might influence shared identity were identified, and they were explored in lab experiments in study 3 and study 4.
Together, these studies have shown that: (1) the social identity model was useful in China and Ireland, and in an earthquake and a flood; (2) the trajectory of social identity could be short or long, and it could develop into several different subtypes, however, it did not seem to be a consequence of time per se, rather, it was caused by shared fate or shared memory; (3) severity of disaster, pre-existing unity, observed unity, and time were all found to have influenced the level of shared identity.
2020-12-01T00:00:00ZZhang, MengGroup processes in emergencies and disasters have been studied for decades by psychologists, and they have developed many theories to explain collective behaviours. One of the most recent and reasonable theoretical frameworks is the social identity model. The social identity model posits that it is the shared social identity that underpins various group behaviours, especially solidary behaviours, which were widely observed and reported in previous research. While there was abundant research showing that validated the social identity approach, there were still many questions unanswered. The present research sought to answer three general questions: (1) can the social identity model of collective behaviours in emergencies and disasters be applied in a non-Western background? (2) how does shared identity develop over time? (3) what factors may enhance or undermine the strength of shared identity?
Four studies were designed to answer these questions. Study 1 and study 2 were two field studies adopting an ethnographic approach. They sought to explore the research questions in general, but in two different settings – one about an earthquake in China, and the other about a flood in Ireland. By comparing the results of the two field studies, four factors that might influence shared identity were identified, and they were explored in lab experiments in study 3 and study 4.
Together, these studies have shown that: (1) the social identity model was useful in China and Ireland, and in an earthquake and a flood; (2) the trajectory of social identity could be short or long, and it could develop into several different subtypes, however, it did not seem to be a consequence of time per se, rather, it was caused by shared fate or shared memory; (3) severity of disaster, pre-existing unity, observed unity, and time were all found to have influenced the level of shared identity.Inferring unseen causes : exploring the developmental and evolutionary originsCivelek, Zeynephttps://hdl.handle.net/10023/202872021-07-27T09:52:13Z2020-07-30T00:00:00ZHuman adults excel at inferring and exploiting the causal relations in the world. This certainly contributed to the unprecedented advancements in many areas of life from technology to health and astronomy, not seen in other non-human species. What might have led to this capacity? Is the ability to identify causal relations a uniquely human ability? When does it emerge in human development? Do we represent our environments in fundamentally different ways than other non-human animals? In this thesis, I aimed to expand our understanding concerning these questions. If this is a core human capacity, we may find its precursors in other non-human primates. On the other hand, it may be a late emerging capacity in childhood with the development of language and through cultural input. Then there may not be a continuity with other primates.
In my theoretical chapters, I brought together the previous literature to identify the factors that might have facilitated and/or hampered children’s and non-human primates’ performances while they were dealing with causal reasoning tasks. In the light of the challenges presented by this type of research and my goals, I proposed novel paradigms that are suitable to test causal reasoning abilities of young children, chimpanzees and capuchin monkeys.
In three studies, I found that by 4-years of age children were able to infer causal relations based on evidence alone. Three-year-olds did not succeed in the tasks but seemed to have benefited from verbal scaffolding provided by the experimenter. The performance of the chimpanzees and capuchins did not lead to decisive conclusions towards the lack or the presence of this capacity. However, the findings highlighted the importance of prior experience in animal learning. The results and their implications are further discussed.
2020-07-30T00:00:00ZCivelek, ZeynepHuman adults excel at inferring and exploiting the causal relations in the world. This certainly contributed to the unprecedented advancements in many areas of life from technology to health and astronomy, not seen in other non-human species. What might have led to this capacity? Is the ability to identify causal relations a uniquely human ability? When does it emerge in human development? Do we represent our environments in fundamentally different ways than other non-human animals? In this thesis, I aimed to expand our understanding concerning these questions. If this is a core human capacity, we may find its precursors in other non-human primates. On the other hand, it may be a late emerging capacity in childhood with the development of language and through cultural input. Then there may not be a continuity with other primates.
In my theoretical chapters, I brought together the previous literature to identify the factors that might have facilitated and/or hampered children’s and non-human primates’ performances while they were dealing with causal reasoning tasks. In the light of the challenges presented by this type of research and my goals, I proposed novel paradigms that are suitable to test causal reasoning abilities of young children, chimpanzees and capuchin monkeys.
In three studies, I found that by 4-years of age children were able to infer causal relations based on evidence alone. Three-year-olds did not succeed in the tasks but seemed to have benefited from verbal scaffolding provided by the experimenter. The performance of the chimpanzees and capuchins did not lead to decisive conclusions towards the lack or the presence of this capacity. However, the findings highlighted the importance of prior experience in animal learning. The results and their implications are further discussed.Title redactedHoliday, Alison Ruthhttps://hdl.handle.net/10023/195902021-04-19T15:06:13Z2019-12-03T00:00:00Z2019-12-03T00:00:00ZHoliday, Alison RuthGroup-level prosocial behaviour and social identity : an analysis of appeals for support in anti-deportation campaignsRyan, Caoimhehttps://hdl.handle.net/10023/194342020-02-10T09:19:49Z2016-06-22T00:00:00Z2016-06-22T00:00:00ZRyan, CaoimheTesting the predictive coding account of temporal integration in the human visual system : a computational and behavioural studyAitken, Fraserhttps://hdl.handle.net/10023/191582021-04-19T14:07:01Z2019-12-03T00:00:00ZA major goal of vision science is to understand how the visual system maintains behaviourally
relevant perceptions given the level of uncertainty in the signals it receives. One proposed solution is
that the visual system applies predictive coding to its inputs based on the integration of prior
knowledge and current stimulus features. However, support for some vital aspects of predictive
coding in the temporal domain is lacking and simpler accounts of temporal integration also exist. The
aim of this thesis was to test two key attributes of predictive coding in time a) does the visual system
apply adaptive weighting to prediction errors and b) can the visual system apply probabilistic
information learnt from stimulus sequences when making predictions. In chapters 3 & 4, we tested
predictive coding’s ideas of how prediction errors are weighted under the theoretical guidance of a
temporal integration model linked to predictive processing, called the Kalman filter. Here, both
experiments supported predictive coding. We showed that, consistent with the Kalman filter, visual
estimates and the way estimation errors were corrected, adapted to stimulus behaviour and viewing
conditions. In chapter 5, we assessed the ability of the visual system to integrate conditional
relationships present in sequences of stimuli when making predictions. To do this, we inserted a
stimulus sequence that changed and omitted trials based on Markov transition probabilities that made some transitions more or less probable and assessed reaction times and omission trial responses.
Reaction time data was consistent with predictive coding, in that more predictable changes elicited
faster responses. Omission trials data, was though, less clear. When faced with no stimulus,
participants did not apply the conditional probabilities in their decisions optimally, instead applying
non optimal decision strategies, inconsistent with predictive coding. In summary, this thesis supports
the predictive coding of temporal integration but questions its application in all situations.
2019-12-03T00:00:00ZAitken, FraserA major goal of vision science is to understand how the visual system maintains behaviourally
relevant perceptions given the level of uncertainty in the signals it receives. One proposed solution is
that the visual system applies predictive coding to its inputs based on the integration of prior
knowledge and current stimulus features. However, support for some vital aspects of predictive
coding in the temporal domain is lacking and simpler accounts of temporal integration also exist. The
aim of this thesis was to test two key attributes of predictive coding in time a) does the visual system
apply adaptive weighting to prediction errors and b) can the visual system apply probabilistic
information learnt from stimulus sequences when making predictions. In chapters 3 & 4, we tested
predictive coding’s ideas of how prediction errors are weighted under the theoretical guidance of a
temporal integration model linked to predictive processing, called the Kalman filter. Here, both
experiments supported predictive coding. We showed that, consistent with the Kalman filter, visual
estimates and the way estimation errors were corrected, adapted to stimulus behaviour and viewing
conditions. In chapter 5, we assessed the ability of the visual system to integrate conditional
relationships present in sequences of stimuli when making predictions. To do this, we inserted a
stimulus sequence that changed and omitted trials based on Markov transition probabilities that made some transitions more or less probable and assessed reaction times and omission trial responses.
Reaction time data was consistent with predictive coding, in that more predictable changes elicited
faster responses. Omission trials data, was though, less clear. When faced with no stimulus,
participants did not apply the conditional probabilities in their decisions optimally, instead applying
non optimal decision strategies, inconsistent with predictive coding. In summary, this thesis supports
the predictive coding of temporal integration but questions its application in all situations.Tool use in great apes and human children : the impact of prior experience and visual feedbackEbel, Sonja Jördishttps://hdl.handle.net/10023/189682021-03-18T10:59:49Z2019-06-28T00:00:00ZHuman and primate tool use has been the focus of intensive research for many
decades. Studies with non-human great apes are of special interest for the question
when certain cognitive abilities evolved. This thesis investigates the role of prior
experience and visual feedback in great apes’ and human children’s tool use. Prior
experience with tools is normally regarded as beneficial, helping individuals to find
successful strategies. Also, visual feedback and additional information about the
solution of a problem can deliver crucial insight into task components. Following an
introductory and a methodological chapter, Chapter 3 explores the role of visual
feedback and additional information in great ape problem-solving using the Floating
Peanut Task (FPT), which requires pouring water into a tube to extract an object.
Findings suggest that visual feedback was necessary for success at first, but later
became redundant, and end-state information (seeing a water-filled tube) helped
some individuals independently.
As a downside of experience, familiar strategies may restrict the analysis of novel
problems. Most interestingly, prior use of a tool can discourage using it with a novel
function (functional fixedness effect). Chapter 4 investigates functional fixedness in 6- to 8-year-old children using the FPT, focusing on how prior tool use and task
presentation predict success. Findings suggest low success rates overall and no effect
of experience; however, greater tool salience increased success. Chapter 5 investigates
functional fixedness in great apes, varying their experience with three tools to be used
each with a novel function. Prior experience lowered success and increased latency on novel problems, and prior use as a food item kept apes from using a bread stick as a
raking tool. Chapter 6 discusses the overall findings in terms of the evolutionary origins
of the negative impact of prior experience with tools, object representations, and
learning mechanisms.
2019-06-28T00:00:00ZEbel, Sonja JördisHuman and primate tool use has been the focus of intensive research for many
decades. Studies with non-human great apes are of special interest for the question
when certain cognitive abilities evolved. This thesis investigates the role of prior
experience and visual feedback in great apes’ and human children’s tool use. Prior
experience with tools is normally regarded as beneficial, helping individuals to find
successful strategies. Also, visual feedback and additional information about the
solution of a problem can deliver crucial insight into task components. Following an
introductory and a methodological chapter, Chapter 3 explores the role of visual
feedback and additional information in great ape problem-solving using the Floating
Peanut Task (FPT), which requires pouring water into a tube to extract an object.
Findings suggest that visual feedback was necessary for success at first, but later
became redundant, and end-state information (seeing a water-filled tube) helped
some individuals independently.
As a downside of experience, familiar strategies may restrict the analysis of novel
problems. Most interestingly, prior use of a tool can discourage using it with a novel
function (functional fixedness effect). Chapter 4 investigates functional fixedness in 6- to 8-year-old children using the FPT, focusing on how prior tool use and task
presentation predict success. Findings suggest low success rates overall and no effect
of experience; however, greater tool salience increased success. Chapter 5 investigates
functional fixedness in great apes, varying their experience with three tools to be used
each with a novel function. Prior experience lowered success and increased latency on novel problems, and prior use as a food item kept apes from using a bread stick as a
raking tool. Chapter 6 discusses the overall findings in terms of the evolutionary origins
of the negative impact of prior experience with tools, object representations, and
learning mechanisms.Exploring depth and distance perception in strabismusZlatkute, Giedrehttps://hdl.handle.net/10023/189592021-04-20T15:48:36Z2019-12-03T00:00:00ZStrabismus can be defined as the inability to coordinate the eye muscles that ordinarily fixate the two eyes on a single target, resulting in lack of a single binocular vision. Strabismus as a disorder has been known since the times of Hippocrates. However, the exact extent of the limitations in depth and distance perception in strabismic individuals with limited or no binocular stereovision in comparison to typically developed binocular individuals remains unclear. This thesis aimed to explore differences in depth perception between strabismic and non-strabismic individuals by examining qualitative aspects of depth perception, egocentric distance perception, and relative depth perception. These aspects were examined by conducting two experiments for each. The first two experiments revealed that feeling of immersive and tangible depth (a.k.a. stereopsis) is not uniquely linked to binocular disparities and may be experienced by individuals with varying levels of binocular stereovision under monocular aperture viewing (evoking monocular stereopsis). The next two experiments explored egocentric distance perception by measuring familiar object size judgments (as a proxy for distance perception) under monocular, binocular, and stereoscopic viewing. All subjects made similar size judgments under all viewing conditions. The last two experiments showed that observers with no/limited stereovision do not have deficits in the perception of relative depth from perspective cues. They showed similar levels of susceptibility and capacity to make depth judgements from the perspective cue to those of stereonormal individuals. The results of this thesis add systematic insight into understanding the way individuals with strabismus perceive depth and distance in comparison to typically developed binocular individuals. Overall, it suggests that there are more similarities between these two groups in the perception of 3D space than suggested by anecdotal reports and conjecture. This emphasizes the need for further systematic exploration to determine the specific limitations strabismics face whilst performing everyday tasks.
2019-12-03T00:00:00ZZlatkute, GiedreStrabismus can be defined as the inability to coordinate the eye muscles that ordinarily fixate the two eyes on a single target, resulting in lack of a single binocular vision. Strabismus as a disorder has been known since the times of Hippocrates. However, the exact extent of the limitations in depth and distance perception in strabismic individuals with limited or no binocular stereovision in comparison to typically developed binocular individuals remains unclear. This thesis aimed to explore differences in depth perception between strabismic and non-strabismic individuals by examining qualitative aspects of depth perception, egocentric distance perception, and relative depth perception. These aspects were examined by conducting two experiments for each. The first two experiments revealed that feeling of immersive and tangible depth (a.k.a. stereopsis) is not uniquely linked to binocular disparities and may be experienced by individuals with varying levels of binocular stereovision under monocular aperture viewing (evoking monocular stereopsis). The next two experiments explored egocentric distance perception by measuring familiar object size judgments (as a proxy for distance perception) under monocular, binocular, and stereoscopic viewing. All subjects made similar size judgments under all viewing conditions. The last two experiments showed that observers with no/limited stereovision do not have deficits in the perception of relative depth from perspective cues. They showed similar levels of susceptibility and capacity to make depth judgements from the perspective cue to those of stereonormal individuals. The results of this thesis add systematic insight into understanding the way individuals with strabismus perceive depth and distance in comparison to typically developed binocular individuals. Overall, it suggests that there are more similarities between these two groups in the perception of 3D space than suggested by anecdotal reports and conjecture. This emphasizes the need for further systematic exploration to determine the specific limitations strabismics face whilst performing everyday tasks.The visual processing of speed in two and three dimensionsLee, Abigail Rachael Inglehttps://hdl.handle.net/10023/189352021-02-16T15:03:46Z2020-06-26T00:00:00ZAs animals that move in a 3D world and interact with 3D objects, it is very important for our survival that our visual systems provide two- and three-dimensional motion perception. Over 4 experimental chapters, we used psychophysical methods to consider several questions about how the human brain processes speed information in two and three dimensions.
In Chapter 2, we investigated whether making three-dimensional motion more realistic than in many previous human vision studies, by adding accelerations on the retina to our stimuli, improved our ability to discriminate speed changes. We found that adding retinal acceleration to our stimuli did not offer performance enhancement.
In Chapter 3, we wanted to understand whether monocular or binocular cues were more important for discriminating speed changes for motion in depth. Our results were inconclusive, but the apparent difficulty of the speed change discrimination task led us to compare performance in these tasks to that for speed discrimination: we found speed change discrimination to be more difficult. It is often possible to use distance or duration information for speed discrimination, but not for speed change discrimination, so we also investigated whether participants use speed information for speed discrimination. Participants used a range of cues, and may have changed the cue they used from trial to trial.
In Chapter 4, we investigated with novel experimental designs whether participants used speed, distance, duration or a combination of cues to make speed and speed change discrimination judgements. We found participants used speed information alone for both tasks.
Finally, in Chapter 5 we considered whether speed change discrimination was difficult because speed information was combined over space or time. Neither combination of speed information across time, or across space, was responsible speed change discrimination difficulty. Overall, our findings contribute to our understanding of speed perception for moving objects.
2020-06-26T00:00:00ZLee, Abigail Rachael IngleAs animals that move in a 3D world and interact with 3D objects, it is very important for our survival that our visual systems provide two- and three-dimensional motion perception. Over 4 experimental chapters, we used psychophysical methods to consider several questions about how the human brain processes speed information in two and three dimensions.
In Chapter 2, we investigated whether making three-dimensional motion more realistic than in many previous human vision studies, by adding accelerations on the retina to our stimuli, improved our ability to discriminate speed changes. We found that adding retinal acceleration to our stimuli did not offer performance enhancement.
In Chapter 3, we wanted to understand whether monocular or binocular cues were more important for discriminating speed changes for motion in depth. Our results were inconclusive, but the apparent difficulty of the speed change discrimination task led us to compare performance in these tasks to that for speed discrimination: we found speed change discrimination to be more difficult. It is often possible to use distance or duration information for speed discrimination, but not for speed change discrimination, so we also investigated whether participants use speed information for speed discrimination. Participants used a range of cues, and may have changed the cue they used from trial to trial.
In Chapter 4, we investigated with novel experimental designs whether participants used speed, distance, duration or a combination of cues to make speed and speed change discrimination judgements. We found participants used speed information alone for both tasks.
Finally, in Chapter 5 we considered whether speed change discrimination was difficult because speed information was combined over space or time. Neither combination of speed information across time, or across space, was responsible speed change discrimination difficulty. Overall, our findings contribute to our understanding of speed perception for moving objects.Investigating the pathophysiology of amyotrophic lateral sclerosis (ALS) using motoneurons and astrocytes derived from induced pluripotent stem cells obtained from ALS patientsChouhan, Amit Kumarhttps://hdl.handle.net/10023/188872021-04-16T08:56:24Z2019-12-03T00:00:00Z2019-12-03T00:00:00ZChouhan, Amit KumarWhat drives bias? : an investigation into the anatomy of extra-oculomotor proprioception and its role in spatial neglectMitchell, Alexandra Gracehttps://hdl.handle.net/10023/188462022-08-29T13:53:52Z2019-12-03T00:00:00Z2019-12-03T00:00:00ZMitchell, Alexandra GraceMeaning and context in the gestural communication of wild bilia (bonobo: Pan paniscus)Graham, Kirsty Emmahttps://hdl.handle.net/10023/185612019-09-27T12:07:52Z2017-06-20T00:00:00ZStudying the communication of our closest living relatives, the great apes, can inform our understanding of language evolution. Great ape gestural communication has been well-documented in captivity, but less so in the wild, with the exception of the chimpanzee. My research on the gestural communication of wild bonobos (at Wamba, Democratic Republic of the Congo) aims to fill one of the gaps in our knowledge. In my thesis, I first describe the gestural repertoire of wild bonobos –the physical form of the gestures that they use. The Wamba communities of wild bonobos use 68 gesture types. I then look at the meaning of gestures by analysing the Apparently Satisfactory Outcome (ASO) that they achieve. Of the gesture types that are suitable for analysis, about half have only one ASO, while the other half achieve multiple ASOs. Where these meanings are ambiguous, with one gesture type achieving multiple ASOs, I look at potential modifiers: syntax-like sequence ordering, and behavioural and interpersonal context. There is no effect of sequence order on the meaning of gestures; rather, the behavioural and interpersonal context explains the apparent ambiguity. Gesture types mean different things in different contexts. Finally, I take my findings and compare them to data from wild chimpanzees at Budongo, Uganda. The gestural repertoire (the physical form of the gestures) overlaps by 88-96%, and many ASOs are achieved by the same gesture types. However, the distribution of gesture types for each ASO is different between species, possibly as a result of different contexts arising from differences in social behaviour.
2017-06-20T00:00:00ZGraham, Kirsty EmmaStudying the communication of our closest living relatives, the great apes, can inform our understanding of language evolution. Great ape gestural communication has been well-documented in captivity, but less so in the wild, with the exception of the chimpanzee. My research on the gestural communication of wild bonobos (at Wamba, Democratic Republic of the Congo) aims to fill one of the gaps in our knowledge. In my thesis, I first describe the gestural repertoire of wild bonobos –the physical form of the gestures that they use. The Wamba communities of wild bonobos use 68 gesture types. I then look at the meaning of gestures by analysing the Apparently Satisfactory Outcome (ASO) that they achieve. Of the gesture types that are suitable for analysis, about half have only one ASO, while the other half achieve multiple ASOs. Where these meanings are ambiguous, with one gesture type achieving multiple ASOs, I look at potential modifiers: syntax-like sequence ordering, and behavioural and interpersonal context. There is no effect of sequence order on the meaning of gestures; rather, the behavioural and interpersonal context explains the apparent ambiguity. Gesture types mean different things in different contexts. Finally, I take my findings and compare them to data from wild chimpanzees at Budongo, Uganda. The gestural repertoire (the physical form of the gestures) overlaps by 88-96%, and many ASOs are achieved by the same gesture types. However, the distribution of gesture types for each ASO is different between species, possibly as a result of different contexts arising from differences in social behaviour.Event-related potential correlates of encoding and retrieval processes in human memoryDoyle, Hughhttps://hdl.handle.net/10023/183892019-08-30T02:05:55Z1990-03-09T00:00:00ZIn
electrophysiological research over the last few years there has been
a
growing tendency to utilise the Event-Related Potential as a tool in the
study of cognitive processes, especially those which are well defined and
understood. Over the last few years too, the study of encoding and
retrieval processes in human memory has achieved a certain measure of
consensus, in that many researchers have suggested that retrieval
performance depends largely upon the type of encoding process performed
upon the item at presentation, in particular it is suggested that the
degree to which the physical characteristics of a stimulus item are
analysed will largely determine whether the item can later be recognised
and that the degree to which the semantic content of the item is analysed
will
largely determine whether the item can later be recalled. The present
series of experiments sought to determine whether there existed ERP
correlates of the two
types of encoding process and of the two related
retrieval processes, recognition and recall.
In the first experiment, ERPs generated by words which were thought to
have been analysed at a physical level, as determined by whether they were
recognised 24 hours later, were compared with ERPs generated by words
thought not to have received such processing, during both initial and
subsequent presentation. The ERP encoding data indicated that enhancement
was seen in late positive activity generated at Fz by words which were
later
recognised with a high degree of confidence. This was taken to imply
that the enhanced positivity was generated by elaborative encoding
processes. The ERP retrieval data indicated: 1) that between 300-500 msec
post stimulus, words which were correctly recognised as "old" generated
potentials of greater positivity than words which were correctly recognised
as "new". This was
interpreted as an ERP index of a retrieval process based
on
familiarity only. 2) Between 500-924 msec post stimulus, items which
may have been recognised due to the retrieval of encoding context generated
greater positivity than items recognised on the basis of familiarity alone.
In experiment 2, the basic design was repeated with the exception that
a
cognitive task was interposed between trials to ensure that all
processing related to subsequent memory performance was restricted to the
recording epoch. ERPs were recorded only during the initial presentation
of stimulus
items, and those generated by words later recognised were again
compared with those generated by items not recognised or recognised with
low confidence. The ERP data revealed the same enhanced late positivity at
Fz
generated by words correctly recognised with a high degree of
confidence, although, as in experiment 1, the effect was small.
In
experiment 3, ERPs were again only recorded to words during the
first
presentation, but were this time compared on the basis of whether
words had been recalled or not. It was
thought that if subsequent recall
of items
depends on elaborative processing at presentation, this
manipulation would ensure that ERPs generated by recalled words would
reflect
activity selective to elaborative encoding. The recording epoch was
also lengthened in order that the ERPs might be sensitive to slow, long
latency effects. The data indicated that words which were recalled
generated ERPs of significantly greater positivity in the region 800-1400
msec at Fz than did words not recalled.
In
experiment 4, ERPs generated by words during retrieval were
recorded, and in this case ERPs generated by words whose experimentally
learned associates were recalled from memory, were compared with ERPs
generated by words whose associates were not recalled. It was suggested
that since recall depends upon retrieval of encoding context, ERPs
generated by words whose learned associates were recalled, should reflect
such
processing. The ERP data showed that words whose associates were
recalled, generated activity of greater positivity than words whose
associates were not
recalled, from 500 msec onwards at all three midline
sites.
It is concluded from these experiments that at encoding, the
activation of elaborative processing is reflected by an enhancement of the
ERP
activity at Fz from approx. 500 msec onwards, and that at retrieval, 1)
the activation of the "familiarity-checking" process generates enhanced
positivity at all midline sites between 300-500 msec, and 2) that the
"retrieval of encoding context" process generates enhanced positivity from
500 msec onwards. These data are related further in the conclusion to both
physiological and cognitive theories of human memory.
1990-03-09T00:00:00ZDoyle, HughIn
electrophysiological research over the last few years there has been
a
growing tendency to utilise the Event-Related Potential as a tool in the
study of cognitive processes, especially those which are well defined and
understood. Over the last few years too, the study of encoding and
retrieval processes in human memory has achieved a certain measure of
consensus, in that many researchers have suggested that retrieval
performance depends largely upon the type of encoding process performed
upon the item at presentation, in particular it is suggested that the
degree to which the physical characteristics of a stimulus item are
analysed will largely determine whether the item can later be recognised
and that the degree to which the semantic content of the item is analysed
will
largely determine whether the item can later be recalled. The present
series of experiments sought to determine whether there existed ERP
correlates of the two
types of encoding process and of the two related
retrieval processes, recognition and recall.
In the first experiment, ERPs generated by words which were thought to
have been analysed at a physical level, as determined by whether they were
recognised 24 hours later, were compared with ERPs generated by words
thought not to have received such processing, during both initial and
subsequent presentation. The ERP encoding data indicated that enhancement
was seen in late positive activity generated at Fz by words which were
later
recognised with a high degree of confidence. This was taken to imply
that the enhanced positivity was generated by elaborative encoding
processes. The ERP retrieval data indicated: 1) that between 300-500 msec
post stimulus, words which were correctly recognised as "old" generated
potentials of greater positivity than words which were correctly recognised
as "new". This was
interpreted as an ERP index of a retrieval process based
on
familiarity only. 2) Between 500-924 msec post stimulus, items which
may have been recognised due to the retrieval of encoding context generated
greater positivity than items recognised on the basis of familiarity alone.
In experiment 2, the basic design was repeated with the exception that
a
cognitive task was interposed between trials to ensure that all
processing related to subsequent memory performance was restricted to the
recording epoch. ERPs were recorded only during the initial presentation
of stimulus
items, and those generated by words later recognised were again
compared with those generated by items not recognised or recognised with
low confidence. The ERP data revealed the same enhanced late positivity at
Fz
generated by words correctly recognised with a high degree of
confidence, although, as in experiment 1, the effect was small.
In
experiment 3, ERPs were again only recorded to words during the
first
presentation, but were this time compared on the basis of whether
words had been recalled or not. It was
thought that if subsequent recall
of items
depends on elaborative processing at presentation, this
manipulation would ensure that ERPs generated by recalled words would
reflect
activity selective to elaborative encoding. The recording epoch was
also lengthened in order that the ERPs might be sensitive to slow, long
latency effects. The data indicated that words which were recalled
generated ERPs of significantly greater positivity in the region 800-1400
msec at Fz than did words not recalled.
In
experiment 4, ERPs generated by words during retrieval were
recorded, and in this case ERPs generated by words whose experimentally
learned associates were recalled from memory, were compared with ERPs
generated by words whose associates were not recalled. It was suggested
that since recall depends upon retrieval of encoding context, ERPs
generated by words whose learned associates were recalled, should reflect
such
processing. The ERP data showed that words whose associates were
recalled, generated activity of greater positivity than words whose
associates were not
recalled, from 500 msec onwards at all three midline
sites.
It is concluded from these experiments that at encoding, the
activation of elaborative processing is reflected by an enhancement of the
ERP
activity at Fz from approx. 500 msec onwards, and that at retrieval, 1)
the activation of the "familiarity-checking" process generates enhanced
positivity at all midline sites between 300-500 msec, and 2) that the
"retrieval of encoding context" process generates enhanced positivity from
500 msec onwards. These data are related further in the conclusion to both
physiological and cognitive theories of human memory.Laminar contributions of superficial lateral entorhinal cortex to episodic memoryVandrey, Briannahttps://hdl.handle.net/10023/179872022-12-03T03:06:19Z2018-07-01T00:00:00ZEpisodic memory relies on the hippocampus and its surrounding cortical network. The
superficial layers of the entorhinal cortex provide substantial input to the hippocampus within
this network. Recent evidence suggests that the lateral entorhinal cortex (LEC) is critical for
binding together features of an episode, and single neurons in the LEC encode spatial
information about local cues in the environment. However, the relationship between
entorhinal-hippocampal circuit components and cognition is unclear. Therefore, the
experiments presented in this thesis investigated the functional contributions of projections to
the hippocampus from the superficial LEC (layers 2/3; L2/3) to associative memory processes.
First, I examined whether input from entorhinal cortex influences the activity of place cells in
the CA1 region of the hippocampus. In an environment which contained objects, place cells
which receive direct input from LEC L3 demonstrated a higher degree of spatial tuning than
place cells which receive input from MEC L3, and exhibited firing patterns which were
precisely tied to current and previous object locations. However, further elucidation of this
finding was precluded by the lack of a tool which permits the selective manipulation the
superficial LEC layers. Therefore, a second set of experiments investigated the arrangement of
projecting neurons in LEC L2 and identified a molecular tool, the Sim1:Cre mouse, which
permits the precise manipulation of excitatory neurons in LEC L2 which are positive for the
protein reelin and project to the dentate gyrus. A final experiment selectively suppressed the
output from these neurons in a cohort of Sim1:Cre mice and examined performance on a series
of object-based recognition memory tasks. Indeed, inactivation of this pathway resulted in
profound impairment on an episodic memory task and mildly impaired novel object
recognition. Overall, these data suggest that projections from the superficial LEC to the
hippocampus make critical contributions to associative memory processes.
2018-07-01T00:00:00ZVandrey, BriannaEpisodic memory relies on the hippocampus and its surrounding cortical network. The
superficial layers of the entorhinal cortex provide substantial input to the hippocampus within
this network. Recent evidence suggests that the lateral entorhinal cortex (LEC) is critical for
binding together features of an episode, and single neurons in the LEC encode spatial
information about local cues in the environment. However, the relationship between
entorhinal-hippocampal circuit components and cognition is unclear. Therefore, the
experiments presented in this thesis investigated the functional contributions of projections to
the hippocampus from the superficial LEC (layers 2/3; L2/3) to associative memory processes.
First, I examined whether input from entorhinal cortex influences the activity of place cells in
the CA1 region of the hippocampus. In an environment which contained objects, place cells
which receive direct input from LEC L3 demonstrated a higher degree of spatial tuning than
place cells which receive input from MEC L3, and exhibited firing patterns which were
precisely tied to current and previous object locations. However, further elucidation of this
finding was precluded by the lack of a tool which permits the selective manipulation the
superficial LEC layers. Therefore, a second set of experiments investigated the arrangement of
projecting neurons in LEC L2 and identified a molecular tool, the Sim1:Cre mouse, which
permits the precise manipulation of excitatory neurons in LEC L2 which are positive for the
protein reelin and project to the dentate gyrus. A final experiment selectively suppressed the
output from these neurons in a cohort of Sim1:Cre mice and examined performance on a series
of object-based recognition memory tasks. Indeed, inactivation of this pathway resulted in
profound impairment on an episodic memory task and mildly impaired novel object
recognition. Overall, these data suggest that projections from the superficial LEC to the
hippocampus make critical contributions to associative memory processes.Targeting benefits and interactions in multisensory processing : a novel modelling framework for exploring the redundant signal effectInnes, Bobby Richardhttps://hdl.handle.net/10023/179682023-05-06T02:01:45Z2019-06-28T00:00:00ZAn overarching goal of multisensory research is to understand the rules by which multiple sensory signals are combined to produce behavioural benefits. One example of a multisensory benefit is that response times (RTs) to multisensory signals are faster than RTs to either component unisensory signal (the redundant signal effect). In contrast to other areas of multisensory research, a common explanatory model framework (and thus the basic combination rule) has yet to emerge for multisensory RT benefits. One key reason for this lack of progress would seem to be that additional processing interactions are infrequently quantified, and are rarely incorporated into a formal model of RTs. In this thesis, I assess the ability of a previously-neglected model class – so called race models – to account for both benefits and interactions. To do so, I develop and apply a comparative approach to RT analysis. This approach tests different experimental factors which attempt target sources of benefits and interactions. The effect of these manipulations is compared across 3 key analytical steps. First, the size of the multisensory benefit (i.e. the redundant signal effect) is computed, and compared to the basic prediction of the race model combination rule. Second, indicators of processing
interactions beyond the basic combination rule are quantified. Third, a formal race model is applied to explain benefits and processing interactions. By consistently applying this comparative approach, I demonstrate that the race model framework offers a simple yet powerful account of multisensory benefits across participants. This suggests a basic combination rule for multisensory RT benefits. In addition, a new interpretation of interactions emerges by applying a race model framework, which highlights an important role of context. This approach suggests a common foundation for future studies of multisensory RTs, which can implement the same analytical steps within a wide range of experimental contexts.
2019-06-28T00:00:00ZInnes, Bobby RichardAn overarching goal of multisensory research is to understand the rules by which multiple sensory signals are combined to produce behavioural benefits. One example of a multisensory benefit is that response times (RTs) to multisensory signals are faster than RTs to either component unisensory signal (the redundant signal effect). In contrast to other areas of multisensory research, a common explanatory model framework (and thus the basic combination rule) has yet to emerge for multisensory RT benefits. One key reason for this lack of progress would seem to be that additional processing interactions are infrequently quantified, and are rarely incorporated into a formal model of RTs. In this thesis, I assess the ability of a previously-neglected model class – so called race models – to account for both benefits and interactions. To do so, I develop and apply a comparative approach to RT analysis. This approach tests different experimental factors which attempt target sources of benefits and interactions. The effect of these manipulations is compared across 3 key analytical steps. First, the size of the multisensory benefit (i.e. the redundant signal effect) is computed, and compared to the basic prediction of the race model combination rule. Second, indicators of processing
interactions beyond the basic combination rule are quantified. Third, a formal race model is applied to explain benefits and processing interactions. By consistently applying this comparative approach, I demonstrate that the race model framework offers a simple yet powerful account of multisensory benefits across participants. This suggests a basic combination rule for multisensory RT benefits. In addition, a new interpretation of interactions emerges by applying a race model framework, which highlights an important role of context. This approach suggests a common foundation for future studies of multisensory RTs, which can implement the same analytical steps within a wide range of experimental contexts.Cooperation and teaching in the context of cumulative cultureNolte, Suskahttps://hdl.handle.net/10023/178972021-03-10T15:24:15Z2019-06-28T00:00:00ZCumulative culture enables humans to shape their niche and to live in extreme
environments. To understand the factors enabling cumulative culture, we need to
understand which cognitive abilities support it, how they develop through life, and
how they evolved. Different hypotheses have been put forward as to which cognitive
abilities – namely innovation, imitation, teaching, and cooperation – are most
essential for the emergence of cumulative culture. In this dissertation I review
evidence for each these abilities and discuss three studies that I conducted to
investigate the latter two concepts – teaching, and cooperation. The first study used
a tool-exchange paradigm to compare the altruistic and cooperative abilities of our
two closest living relatives, chimpanzees and bonobos. Bonobos were more likely to
transfer tools to a partner than chimpanzees in both an altruistic and cooperative
context. The second study investigated the ability of chimpanzees to teach new skills
to an ignorant conspecific. I found no evidence that chimpanzees were able to teach,
even with incentives to do so. This is very different to the behaviour of children in
the final study. In this study I investigated whether children, between the ages four
to seven years, would teach an ignorant partner and whether the strategies
employed depended on their age or the potential benefits of successful teaching.
Children of all age groups taught their partner and employed a variety of teaching
strategies. Children used more iconic gestures and explanations (i.e. information the
partner could directly enact) when they would benefit from having a competent
partner rather than a partner whose actions did not result in benefits. I discuss the
results of these studies in terms of their implication for the debate on the evolution
of cumulative culture and will argue that flexible teaching and enhanced altruistic
motivation enabled modern humans to outcompete most species with which we
share the planet.
2019-06-28T00:00:00ZNolte, SuskaCumulative culture enables humans to shape their niche and to live in extreme
environments. To understand the factors enabling cumulative culture, we need to
understand which cognitive abilities support it, how they develop through life, and
how they evolved. Different hypotheses have been put forward as to which cognitive
abilities – namely innovation, imitation, teaching, and cooperation – are most
essential for the emergence of cumulative culture. In this dissertation I review
evidence for each these abilities and discuss three studies that I conducted to
investigate the latter two concepts – teaching, and cooperation. The first study used
a tool-exchange paradigm to compare the altruistic and cooperative abilities of our
two closest living relatives, chimpanzees and bonobos. Bonobos were more likely to
transfer tools to a partner than chimpanzees in both an altruistic and cooperative
context. The second study investigated the ability of chimpanzees to teach new skills
to an ignorant conspecific. I found no evidence that chimpanzees were able to teach,
even with incentives to do so. This is very different to the behaviour of children in
the final study. In this study I investigated whether children, between the ages four
to seven years, would teach an ignorant partner and whether the strategies
employed depended on their age or the potential benefits of successful teaching.
Children of all age groups taught their partner and employed a variety of teaching
strategies. Children used more iconic gestures and explanations (i.e. information the
partner could directly enact) when they would benefit from having a competent
partner rather than a partner whose actions did not result in benefits. I discuss the
results of these studies in terms of their implication for the debate on the evolution
of cumulative culture and will argue that flexible teaching and enhanced altruistic
motivation enabled modern humans to outcompete most species with which we
share the planet.Stress programming throughout life history : implications for physiological ageingWalker, David Johnhttps://hdl.handle.net/10023/178952024-01-18T16:01:27Z2019-06-28T00:00:00ZStress exposure throughout life can shape ageing phenotypes by causing changes
within an individual’s physiology, such that growth, lifespan and many fitness-related
traits are significantly and sometimes permanently affected. Developmental
increases in glucocorticoids (GCs) and subsequent programming of the
Hypothalamic Pituitary Adrenal (HPA) axis, are considered one of the primary
mechanisms that program these age-related physiological changes. However, it is
unclear how stress experienced throughout life interacts on physiological processes
that may influence the trajectory of the ageing process within an individual. In this
thesis, I used the Japanese quail (Coturnix japonica) to investigate both short and
long-term effects of developmental and adult stress exposure on physiological
processes that are known to be affected by the process of ageing: the neuroimmune
system, neural cell death and survival and maintenance of oxidative balance. I
aimed to establish at which point during life stress elicited the strongest
programming effects; if these effects had physiological costs or benefits for the
ageing individual and if there were cumulative or diminishing effects of repeated
stress exposure on these physiological processes. Within the neuroimmune system,
I found that post-natal stress induced neuroinflammation and caused a reduction in
cell survival in later life within brain regions involved in HPA axis functioning.
Repeated developmental stress also programmed a dampened apoptotic response
in the ageing brain. I also found age and sex-specific effects on apoptosis, cell
survival and oxidative balance measures that depended on the conditions birds
experienced during development. My data show that programmed long-term changes in physiology are most likely driven by elevated GCs during the post-natal
period. My research suggests that these programmed phenotypes may exhibit signs
of accelerated physiological ageing or may be adaptive in promoting swifter and
stronger recovery from subsequent stress exposure in later life.
2019-06-28T00:00:00ZWalker, David JohnStress exposure throughout life can shape ageing phenotypes by causing changes
within an individual’s physiology, such that growth, lifespan and many fitness-related
traits are significantly and sometimes permanently affected. Developmental
increases in glucocorticoids (GCs) and subsequent programming of the
Hypothalamic Pituitary Adrenal (HPA) axis, are considered one of the primary
mechanisms that program these age-related physiological changes. However, it is
unclear how stress experienced throughout life interacts on physiological processes
that may influence the trajectory of the ageing process within an individual. In this
thesis, I used the Japanese quail (Coturnix japonica) to investigate both short and
long-term effects of developmental and adult stress exposure on physiological
processes that are known to be affected by the process of ageing: the neuroimmune
system, neural cell death and survival and maintenance of oxidative balance. I
aimed to establish at which point during life stress elicited the strongest
programming effects; if these effects had physiological costs or benefits for the
ageing individual and if there were cumulative or diminishing effects of repeated
stress exposure on these physiological processes. Within the neuroimmune system,
I found that post-natal stress induced neuroinflammation and caused a reduction in
cell survival in later life within brain regions involved in HPA axis functioning.
Repeated developmental stress also programmed a dampened apoptotic response
in the ageing brain. I also found age and sex-specific effects on apoptosis, cell
survival and oxidative balance measures that depended on the conditions birds
experienced during development. My data show that programmed long-term changes in physiology are most likely driven by elevated GCs during the post-natal
period. My research suggests that these programmed phenotypes may exhibit signs
of accelerated physiological ageing or may be adaptive in promoting swifter and
stronger recovery from subsequent stress exposure in later life.The psychology of crowd policingCronin, Patrick Declanhttps://hdl.handle.net/10023/176582019-05-10T02:06:36Z2001-06-22T00:00:00ZTraditional psychological explanations of crowd theory have decontextualised events
and obscured the fact that crowd incidents are typically inter group encounters. This
has led to research being rooted in the crowd whilst ignoring the other parties who
may be present - including the police - and how events develop as function of the
interaction between the two. The studies reported in this thesis attempted to provide
insights into the decision making of senior public order officers of the Metropolitan
Police utilising a variety of qualitative and quantitative methodologies. Four main
studies are reported. In the first study (of police training) a grounded theory analysis
revealed that the police have a fear of the crowd which is seen in a concern with
provoking violence by being too harsh or permitting violence by being too lenient. The
balance of harshness and leniency is informed by accountability considerations arising
from internal and external sources and the phase of violence the officers perceived
themselves to be in. In the second study, the relationship of accountability and phase
was manipulated in a controlled experimental setting providing supportive evidence for
the grounded theory model. The third was a series of pilot participant observation
studies which looked at the policing of the Muslim festivals of Eid al Fitr and the Sikh
festivals of Vaisakhi. These studies raised practical issues and was used in designing
the fourth study which looked at the 'in vivo' processes of decision making during the
biggest public order event in London of 1999. This confirmed and extended the focus
on the importance of accountability concerns in senior officer decision making; firstly
by showing them to be more complex than was originally thought, secondly by
showing how those in different positions within the police had different accountability
concerns, and thirdly by showing that such different concerns could lead to conflict
between different sections of the police. The implications of this research and the
foundations of future research are also discussed.
2001-06-22T00:00:00ZCronin, Patrick DeclanTraditional psychological explanations of crowd theory have decontextualised events
and obscured the fact that crowd incidents are typically inter group encounters. This
has led to research being rooted in the crowd whilst ignoring the other parties who
may be present - including the police - and how events develop as function of the
interaction between the two. The studies reported in this thesis attempted to provide
insights into the decision making of senior public order officers of the Metropolitan
Police utilising a variety of qualitative and quantitative methodologies. Four main
studies are reported. In the first study (of police training) a grounded theory analysis
revealed that the police have a fear of the crowd which is seen in a concern with
provoking violence by being too harsh or permitting violence by being too lenient. The
balance of harshness and leniency is informed by accountability considerations arising
from internal and external sources and the phase of violence the officers perceived
themselves to be in. In the second study, the relationship of accountability and phase
was manipulated in a controlled experimental setting providing supportive evidence for
the grounded theory model. The third was a series of pilot participant observation
studies which looked at the policing of the Muslim festivals of Eid al Fitr and the Sikh
festivals of Vaisakhi. These studies raised practical issues and was used in designing
the fourth study which looked at the 'in vivo' processes of decision making during the
biggest public order event in London of 1999. This confirmed and extended the focus
on the importance of accountability concerns in senior officer decision making; firstly
by showing them to be more complex than was originally thought, secondly by
showing how those in different positions within the police had different accountability
concerns, and thirdly by showing that such different concerns could lead to conflict
between different sections of the police. The implications of this research and the
foundations of future research are also discussed.Effect of violence and other social indicators on formidability preferences for male faces in ColombiaBorrás Guevara, Martha Luciahttps://hdl.handle.net/10023/173672021-02-19T14:58:10Z2019-06-28T00:00:00ZFacial preferences have been studied in the context of variation in health, media access, education and environmental harshness. This thesis explored the potential influence of violence which has been largely neglected in previous research. Colombia was chosen as field site as it is one of the most violent countries in the world. In such a violent context, preferring partners or allies with greater fighting capacity becomes a matter of survival. Formidability (how big/strong someone is) is a reliable indicator of this capacity and, therefore may be preferred when protection from violence is desired. Facial masculinity and BMI (body mass index which is a measure of weight scaled for height) have been previously associated to fighting capacity. Hence preferences for these two physical traits were studied here.
Study 1 explored whether perceptions/experiences of violence influenced masculinity preferences. Women who had experienced/perceived higher violence and who thought men were dangerous to their children preferred less masculine male faces. Violence affected preferences more than variables previously studied (health, access to media, education, etc.).
Study 2 explored the effect of violence type: domestic and public. In a different population sample from study 1, it was found that the more women fear domestic violence the lower their facial preference for masculinity.
Study 3 explored if public and domestic violence affects preferences for facial cues to BMI. Women considering men to be dangerous to their children showed lower preferences for male facial cues to BMI. Strengthening this finding, study 4 found that women with raised fear of domestic violence showed lower preferences for male facial cues to BMI.
Contradicting the initial prediction, this thesis gives convergent evidence that violence perceptions have negative effects on women’s preferences for formidability in male faces. These preferences may reflect women’s strategy to avoid partners capable of inflicting physical harm to women and their children, particularly within the family household.
2019-06-28T00:00:00ZBorrás Guevara, Martha LuciaFacial preferences have been studied in the context of variation in health, media access, education and environmental harshness. This thesis explored the potential influence of violence which has been largely neglected in previous research. Colombia was chosen as field site as it is one of the most violent countries in the world. In such a violent context, preferring partners or allies with greater fighting capacity becomes a matter of survival. Formidability (how big/strong someone is) is a reliable indicator of this capacity and, therefore may be preferred when protection from violence is desired. Facial masculinity and BMI (body mass index which is a measure of weight scaled for height) have been previously associated to fighting capacity. Hence preferences for these two physical traits were studied here.
Study 1 explored whether perceptions/experiences of violence influenced masculinity preferences. Women who had experienced/perceived higher violence and who thought men were dangerous to their children preferred less masculine male faces. Violence affected preferences more than variables previously studied (health, access to media, education, etc.).
Study 2 explored the effect of violence type: domestic and public. In a different population sample from study 1, it was found that the more women fear domestic violence the lower their facial preference for masculinity.
Study 3 explored if public and domestic violence affects preferences for facial cues to BMI. Women considering men to be dangerous to their children showed lower preferences for male facial cues to BMI. Strengthening this finding, study 4 found that women with raised fear of domestic violence showed lower preferences for male facial cues to BMI.
Contradicting the initial prediction, this thesis gives convergent evidence that violence perceptions have negative effects on women’s preferences for formidability in male faces. These preferences may reflect women’s strategy to avoid partners capable of inflicting physical harm to women and their children, particularly within the family household.Out of Many, One: An Exploration of Shared Identity in CrowdsAnderson, Philip Thomashttps://hdl.handle.net/10023/173082023-10-13T02:01:01Z2019-06-28T00:00:00ZIn a crowd, people sometimes experience a feeling of togetherness and one-ness in which the crowd comes to be seen as ‘we’ and ‘us’ rather than ‘they’ and ‘them’. This thesis explores the psychological process that underlies this feeling of one-ness through the shared identity model of crowd behaviour.
Part of the social identity tradition, the shared identity model makes a key distinction between a social identity that is shared, and a shared identity. The former is instantiated in the representational sense that ‘I am an X’ where X stands for a social category, while the latter is instantiated in the meta-representational sense that ‘We are all Xs together’, a reciprocal recognition of the identity of the self and others.
Qualitative methods, including immersion in crowd events, participant observation, semi-structured interviews both in the field and otherwise, audio diaries, photo-elicitation and focus group discussions were used to explore shared identity in political crowds and in music festival crowds. Field interviews were conducted at three climate change protests, and three focus groups were recruited to discuss their experiences at Scotland’s Climate March 2015. Eighteen participants were recruited for semi-structured interviews about their music festival experiences. All interviews and group discussions were transcribed and analysed using a form of thematic analysis. The results showed evidence of shared identity in the form of participants’ descriptions of ‘we-ness’ and ‘one-ness’, feelings of belonging and feelings of love for others, including strangers, in the crowd.
Factors which lead people to perceive themselves as sharing identity, such as synchronised behaviours and shared emotions, and factors that may be consequences of shared identity, including relational and emotional transformations were identified. The results demonstrate that shared identity is by no means an automatic state, but a nuanced, sometimes subtle and often variable process.
2019-06-28T00:00:00ZAnderson, Philip ThomasIn a crowd, people sometimes experience a feeling of togetherness and one-ness in which the crowd comes to be seen as ‘we’ and ‘us’ rather than ‘they’ and ‘them’. This thesis explores the psychological process that underlies this feeling of one-ness through the shared identity model of crowd behaviour.
Part of the social identity tradition, the shared identity model makes a key distinction between a social identity that is shared, and a shared identity. The former is instantiated in the representational sense that ‘I am an X’ where X stands for a social category, while the latter is instantiated in the meta-representational sense that ‘We are all Xs together’, a reciprocal recognition of the identity of the self and others.
Qualitative methods, including immersion in crowd events, participant observation, semi-structured interviews both in the field and otherwise, audio diaries, photo-elicitation and focus group discussions were used to explore shared identity in political crowds and in music festival crowds. Field interviews were conducted at three climate change protests, and three focus groups were recruited to discuss their experiences at Scotland’s Climate March 2015. Eighteen participants were recruited for semi-structured interviews about their music festival experiences. All interviews and group discussions were transcribed and analysed using a form of thematic analysis. The results showed evidence of shared identity in the form of participants’ descriptions of ‘we-ness’ and ‘one-ness’, feelings of belonging and feelings of love for others, including strangers, in the crowd.
Factors which lead people to perceive themselves as sharing identity, such as synchronised behaviours and shared emotions, and factors that may be consequences of shared identity, including relational and emotional transformations were identified. The results demonstrate that shared identity is by no means an automatic state, but a nuanced, sometimes subtle and often variable process.Attending and knowing together : a new look at joint attention and common knowledge and their role in coordinationSiposova, Barborahttps://hdl.handle.net/10023/171422019-04-01T10:40:18Z2018-11-05T00:00:00ZJoint attention—the ability to coordinate attention to an object or event—is a key feature of human social cognition. Without joint attention, we would not be the cooperating species we are now. Most developmental studies focus on when joint attention emerges, rather than what joint attention actually is, and what consequences it has for different types of interactions. To address this gap, Part I of the thesis provides a new look at joint attention, presenting a systematic framework of four attention levels (from monitoring, to common, mutual, and shared attention) with corresponding distinctions for the knowledge states associated with each level. Cognitive, behavioral, and phenomenological aspects of the different levels are discussed, as well as the functions and consequences the levels have in terms of what kinds of obligations they can support. Part II of the thesis follows on from this in investigating the role of joint attention in facilitating coordination. In two studies, 5- to 7-year-old children played a Stag Hunt coordination game in which they needed to decide whether to cooperate or play individually. During the decision-making phase, the children’s partner either shared attention with them—she made ostensive, communicative eye contact—or looked non-communicatively at them. In Study 1, results showed that communicative looks produced an expectation of cooperation in children. In Study 2, children normatively protested when their partner did not cooperate, thus showing an understanding of the communicative look as a commitment to cooperate. This is the first experimental evidence, in adults or children, that in the right context, communicative, but not non-communicative, looks can signal a commitment. Thus the thesis highlights the special importance of the shared attention level in supporting cooperation
2018-11-05T00:00:00ZSiposova, BarboraJoint attention—the ability to coordinate attention to an object or event—is a key feature of human social cognition. Without joint attention, we would not be the cooperating species we are now. Most developmental studies focus on when joint attention emerges, rather than what joint attention actually is, and what consequences it has for different types of interactions. To address this gap, Part I of the thesis provides a new look at joint attention, presenting a systematic framework of four attention levels (from monitoring, to common, mutual, and shared attention) with corresponding distinctions for the knowledge states associated with each level. Cognitive, behavioral, and phenomenological aspects of the different levels are discussed, as well as the functions and consequences the levels have in terms of what kinds of obligations they can support. Part II of the thesis follows on from this in investigating the role of joint attention in facilitating coordination. In two studies, 5- to 7-year-old children played a Stag Hunt coordination game in which they needed to decide whether to cooperate or play individually. During the decision-making phase, the children’s partner either shared attention with them—she made ostensive, communicative eye contact—or looked non-communicatively at them. In Study 1, results showed that communicative looks produced an expectation of cooperation in children. In Study 2, children normatively protested when their partner did not cooperate, thus showing an understanding of the communicative look as a commitment to cooperate. This is the first experimental evidence, in adults or children, that in the right context, communicative, but not non-communicative, looks can signal a commitment. Thus the thesis highlights the special importance of the shared attention level in supporting cooperationInvestigation of molecular and cellular mechanisms underpinning the neurotoxicity of homocysteine and its metabolites in models of neurodegenerationStrother, Lisahttps://hdl.handle.net/10023/170672019-04-01T10:40:19Z2018-12-06T00:00:00ZElevated levels of homocysteine (HCy) are a known risk factor in several disease states (1).
HCy has several other metabolites, homocysteine thiolactone (HCy-T) and homocysteic acid
(HCA). Whilst HCy-mediated neurotoxicity has been extensively studied, the underlying
mechanisms of HCy-T and HCA mediated neuronal damage remain largely unknown. This
thesis aims to explore the underlying mechanisms, triggered by HCy and metabolites which
result in neuronal cell death, and may be appropriate targets for future research on disease-modifying interventions in neurodegenerative disorders. As ageing is the greatest risk factor for neurodegeneration, a novel model of human neuronal ageing was established, permitting
investigation of the pathways triggered by HCy in ageing.
Using SH-SY5Y cells, a novel differentiation protocol was established and categorised, once
fully differentiated, these cells were shown to be fully functional neurons and could be
maintained for a month in culture. Using a range of concentrations of HCy and HCy-T, the
concentration cell death occurs at was determined using crystal violet and lactate
dehydrogenase assays. Mechanisms of toxicity were determined using pharmacological
intervention at the NMDA receptor, nitric oxide scavengers and antioxidants. Using a
combination of immunocytochemistry, live cell imaging and ELISA, alterations in markers of
cell damage could be examined.
The results showed HCy and HCy-T have distinct mechanisms of toxicity. Whilst both are
neurotoxic, HCy directly acts via the NMDA receptor, however HCy-T appears to be less
potent. Additionally, HCy-T caused a greater increase in reactive oxygen species generation
than HCy, and each metabolite also displayed distinct mitochondrial network abnormalities.
Finally, using the long-term culture methods, the chronic effects of HCy, HCy-T and HCA
were examined. However, extensive cell death was apparent at low doses in all metabolites therefore no definitive mechanisms could be determined. This culture method was deemed not
appropriate for toxicity experiments.
2018-12-06T00:00:00ZStrother, LisaElevated levels of homocysteine (HCy) are a known risk factor in several disease states (1).
HCy has several other metabolites, homocysteine thiolactone (HCy-T) and homocysteic acid
(HCA). Whilst HCy-mediated neurotoxicity has been extensively studied, the underlying
mechanisms of HCy-T and HCA mediated neuronal damage remain largely unknown. This
thesis aims to explore the underlying mechanisms, triggered by HCy and metabolites which
result in neuronal cell death, and may be appropriate targets for future research on disease-modifying interventions in neurodegenerative disorders. As ageing is the greatest risk factor for neurodegeneration, a novel model of human neuronal ageing was established, permitting
investigation of the pathways triggered by HCy in ageing.
Using SH-SY5Y cells, a novel differentiation protocol was established and categorised, once
fully differentiated, these cells were shown to be fully functional neurons and could be
maintained for a month in culture. Using a range of concentrations of HCy and HCy-T, the
concentration cell death occurs at was determined using crystal violet and lactate
dehydrogenase assays. Mechanisms of toxicity were determined using pharmacological
intervention at the NMDA receptor, nitric oxide scavengers and antioxidants. Using a
combination of immunocytochemistry, live cell imaging and ELISA, alterations in markers of
cell damage could be examined.
The results showed HCy and HCy-T have distinct mechanisms of toxicity. Whilst both are
neurotoxic, HCy directly acts via the NMDA receptor, however HCy-T appears to be less
potent. Additionally, HCy-T caused a greater increase in reactive oxygen species generation
than HCy, and each metabolite also displayed distinct mitochondrial network abnormalities.
Finally, using the long-term culture methods, the chronic effects of HCy, HCy-T and HCA
were examined. However, extensive cell death was apparent at low doses in all metabolites therefore no definitive mechanisms could be determined. This culture method was deemed not
appropriate for toxicity experiments.The resilience paradox : flooding experience, coping and climate change mitigation intentionsOgunbode, Charles AdedayoBoehm, GiselaCapstick, StuartDemski, CarolinaSpence, AlexaTausch, Nicolehttps://hdl.handle.net/10023/170642023-04-25T23:55:47Z2018-12-24T00:00:00ZClimate change is projected to increase the frequency, intensity and unpredictability of extreme weather events across the globe and these events are likely to have significant mental health implications. The mental health literature broadly characterises negative emotional reactions to extreme weather experiences as undesirable impacts on wellbeing. Yet, other research in psychology suggests that negative emotional responses to extreme weather are an important motivation for personal action on climate change. This article addresses the intersection of mental health and functional perspectives on negative emotions, with a specific focus on the potential that reduced negative emotional responses to extreme weather may also translate to diminished motivation to undertake climate change mitigation actions – which we term the ‘resilience paradox’. Using survey data gathered in the aftermath of severe flooding across the UK in winter 2013/2014, we present new evidence indicating that self-appraised coping ability moderates the link between flooding experience and negative emotions and thereby attenuates the indirect link between flooding experience and climate change mitigation intentions. We conclude that support for flood victims should extend beyond addressing emotional, physical and financial stresses to include acknowledgement of the involvement of climate change and communication of the need for action to combat future climate risks.
This work was supported by Economic and Social Research Council [grant number ES/M005135/1].
2018-12-24T00:00:00ZOgunbode, Charles AdedayoBoehm, GiselaCapstick, StuartDemski, CarolinaSpence, AlexaTausch, NicoleClimate change is projected to increase the frequency, intensity and unpredictability of extreme weather events across the globe and these events are likely to have significant mental health implications. The mental health literature broadly characterises negative emotional reactions to extreme weather experiences as undesirable impacts on wellbeing. Yet, other research in psychology suggests that negative emotional responses to extreme weather are an important motivation for personal action on climate change. This article addresses the intersection of mental health and functional perspectives on negative emotions, with a specific focus on the potential that reduced negative emotional responses to extreme weather may also translate to diminished motivation to undertake climate change mitigation actions – which we term the ‘resilience paradox’. Using survey data gathered in the aftermath of severe flooding across the UK in winter 2013/2014, we present new evidence indicating that self-appraised coping ability moderates the link between flooding experience and negative emotions and thereby attenuates the indirect link between flooding experience and climate change mitigation intentions. We conclude that support for flood victims should extend beyond addressing emotional, physical and financial stresses to include acknowledgement of the involvement of climate change and communication of the need for action to combat future climate risks.An investigation of the three-tier relationships between
distaste, disgust expression recognition, and moral
responsivityUh, Stephenihttps://hdl.handle.net/10023/169862023-12-01T15:34:04Z2016-06-21T00:00:00ZDisgust is a negative and universal basic emotion that is elicited by a diverse set of sources,
ranging from concrete physical sources (e.g. bad tastes, disease, feces) to abstract social sources (e.g. moral
transgressions and the transgressors). The present study investigated the potential three-tier relationships
between distaste (the proposed evolutionary origin of disgust), disgust sensitivity assessed by facial disgust
recognition measures, and moral responsivity to explore whether: (a) more sensitive bitter tasters had
greater facial disgust recognition accuracy, (b) more sensitive bitter tasters had greater moral responsivity,
and (c) more morally sensitive individuals had greater facial disgust recognition accuracy. The bitter taste
sensitivity test of 6-n-propylthiouracil (PROP), a standard basic Emotion Recognition Task (ERT) (Young
et al., 1997) to measure facial disgust accuracy (“hits”), bias, and false positive errors, and a questionnaire
to assess moral judgments of fairness transgressions from a standardized set compiled by Knuston et al.
(2010) in addition to the moral disgust subscale from The Three Domain Disgust Scale (TDDS) (Tybur et
al., 2009) were administered to 110 participants. Results showed that more sensitive bitter tasters had
greater facial disgust bias rates and a trending association with increased disgust false positive error rates.
There was no significant relationship found between bitter taste sensitivity and moral responsivity.
Interestingly, individuals who found the fairness transgressions less morally inappropriate had a greater
tendency to make more facial disgust false positive errors. These findings indicate that there are different
levels at which distaste, disgust (in the form of facial disgust recognition dimensions), and moral
responsivity are interrelated, providing insight into the multifaceted roles of disgust.
2016-06-21T00:00:00ZUh, StepheniDisgust is a negative and universal basic emotion that is elicited by a diverse set of sources,
ranging from concrete physical sources (e.g. bad tastes, disease, feces) to abstract social sources (e.g. moral
transgressions and the transgressors). The present study investigated the potential three-tier relationships
between distaste (the proposed evolutionary origin of disgust), disgust sensitivity assessed by facial disgust
recognition measures, and moral responsivity to explore whether: (a) more sensitive bitter tasters had
greater facial disgust recognition accuracy, (b) more sensitive bitter tasters had greater moral responsivity,
and (c) more morally sensitive individuals had greater facial disgust recognition accuracy. The bitter taste
sensitivity test of 6-n-propylthiouracil (PROP), a standard basic Emotion Recognition Task (ERT) (Young
et al., 1997) to measure facial disgust accuracy (“hits”), bias, and false positive errors, and a questionnaire
to assess moral judgments of fairness transgressions from a standardized set compiled by Knuston et al.
(2010) in addition to the moral disgust subscale from The Three Domain Disgust Scale (TDDS) (Tybur et
al., 2009) were administered to 110 participants. Results showed that more sensitive bitter tasters had
greater facial disgust bias rates and a trending association with increased disgust false positive error rates.
There was no significant relationship found between bitter taste sensitivity and moral responsivity.
Interestingly, individuals who found the fairness transgressions less morally inappropriate had a greater
tendency to make more facial disgust false positive errors. These findings indicate that there are different
levels at which distaste, disgust (in the form of facial disgust recognition dimensions), and moral
responsivity are interrelated, providing insight into the multifaceted roles of disgust.Experimental studies of behavioural flexibility and cultural transmission in chimpanzees and childrenHarrison, Rachel Annehttps://hdl.handle.net/10023/169542023-03-31T02:01:06Z2019-06-28T00:00:00ZIn this thesis, I explore two subjects of importance to the study of cultural evolution and cumulative culture; behavioural flexibility in chimpanzees, and social transmission in human children. In Chapter 1, I give an overview of current literature on the cognitive requirements of cumulative culture, with a focus on behavioural flexibility as a capacity which facilitates cumulative culture. I also explore a current discussion in the field of cultural evolution; namely the debate between “standard” and cultural attraction-based approaches to the study of cultural evolution. Chapter 2 is an experimental investigation of the capacity of chimpanzees to respond flexibly to a changing foraging task. This study found that chimpanzees did alter their behaviour, but to a limited degree. In Chapter 3 I provide the same artificial foraging task to two further groups of chimpanzees, at a sanctuary in Zambia. This study again found that chimpanzees altered their behaviour in response to task constraints, but also found a significant difference in performance between the two groups tested. Chapter 4 explores one potential factor which may contribute to these group differences; social tolerance. Data on social tolerance from all three groups of chimpanzees is presented. In Chapter 5, I turn to another key factor in the study of culture and also address the cultural attraction approach, by conducting a transmission chain study of four- to eight-year-old human children, comparing the transmission of a symbolic and non-symbolic image. I found that neither image was reliably transmitted along transmission chains. Finally, in Chapter 6, I discuss the findings of the thesis, and suggest that future work considers multiple demographic groups, whether this means the inclusion of multiple groups of apes in studies of non-human primate cognition, or the consideration of how cultural behaviours might be transformed when transmitted by human children rather than adults.
2019-06-28T00:00:00ZHarrison, Rachel AnneIn this thesis, I explore two subjects of importance to the study of cultural evolution and cumulative culture; behavioural flexibility in chimpanzees, and social transmission in human children. In Chapter 1, I give an overview of current literature on the cognitive requirements of cumulative culture, with a focus on behavioural flexibility as a capacity which facilitates cumulative culture. I also explore a current discussion in the field of cultural evolution; namely the debate between “standard” and cultural attraction-based approaches to the study of cultural evolution. Chapter 2 is an experimental investigation of the capacity of chimpanzees to respond flexibly to a changing foraging task. This study found that chimpanzees did alter their behaviour, but to a limited degree. In Chapter 3 I provide the same artificial foraging task to two further groups of chimpanzees, at a sanctuary in Zambia. This study again found that chimpanzees altered their behaviour in response to task constraints, but also found a significant difference in performance between the two groups tested. Chapter 4 explores one potential factor which may contribute to these group differences; social tolerance. Data on social tolerance from all three groups of chimpanzees is presented. In Chapter 5, I turn to another key factor in the study of culture and also address the cultural attraction approach, by conducting a transmission chain study of four- to eight-year-old human children, comparing the transmission of a symbolic and non-symbolic image. I found that neither image was reliably transmitted along transmission chains. Finally, in Chapter 6, I discuss the findings of the thesis, and suggest that future work considers multiple demographic groups, whether this means the inclusion of multiple groups of apes in studies of non-human primate cognition, or the consideration of how cultural behaviours might be transformed when transmitted by human children rather than adults.Life-story narratives,
chapters, and depressionSmith, Katehttps://hdl.handle.net/10023/168112020-04-21T02:03:34Z2017-12-07T00:00:00ZThe structure of life-story narratives and their component chapters is of central
importance to the cognitive representations and communication of autobiographical memory.
While evidence points to the hierarchical role of chapters in autobiographical summations
and abstractions of periods of time, and life-time periods feature as a fundamental
characteristic of the most prominent model of autobiographical memory, few researchers
have attempted to examine their existence as unique units of representation, and their impact
on the recall of episodic events. The present thesis sets out to establish the nature of lifestories
using
established
methods
for
life-story
narrative
and
chapter
elucidation
and
a
novel
paradigm
for
examining
memory
recall
from
within
chapters.
It
does
so
by
contrasting
the
impact
of
life
story
chapters
for
people
with
depression
against
non-depressed
groups,
and
in
doing
so
finds
evidence
for
chapters
acting
as
affective
schema
for
autobiographical
periods,
and
access to episodic events, with an overall raised access for incongruent event
representations. The findings of this thesis also indicate that narrative disorder in depression
is not reliably present (Studies one and two) and that chapters, while more negative in tone
(Studies two and three), may not be structurally different for dysphoric narratives compared
to control groups (Study two). The schematic role of chapters in the recall of episodic
memories, indicates a tendency in depression to display a negative bias in dissonance
reduction between negative chapters and positive events (Study four).
This thesis provides evidence that depression is linked to a negative bias in the higher-
order chapter level of autobiographical memory, and that due to dissonance reduction
processes, and the rehearsal of affectively congruent event-based representations, people with
depression may have reduced access to positive material which would be used in mood repair
and the creation of positive variation to their life-stories by drawing on specific events.
2017-12-07T00:00:00ZSmith, KateThe structure of life-story narratives and their component chapters is of central
importance to the cognitive representations and communication of autobiographical memory.
While evidence points to the hierarchical role of chapters in autobiographical summations
and abstractions of periods of time, and life-time periods feature as a fundamental
characteristic of the most prominent model of autobiographical memory, few researchers
have attempted to examine their existence as unique units of representation, and their impact
on the recall of episodic events. The present thesis sets out to establish the nature of lifestories
using
established
methods
for
life-story
narrative
and
chapter
elucidation
and
a
novel
paradigm
for
examining
memory
recall
from
within
chapters.
It
does
so
by
contrasting
the
impact
of
life
story
chapters
for
people
with
depression
against
non-depressed
groups,
and
in
doing
so
finds
evidence
for
chapters
acting
as
affective
schema
for
autobiographical
periods,
and
access to episodic events, with an overall raised access for incongruent event
representations. The findings of this thesis also indicate that narrative disorder in depression
is not reliably present (Studies one and two) and that chapters, while more negative in tone
(Studies two and three), may not be structurally different for dysphoric narratives compared
to control groups (Study two). The schematic role of chapters in the recall of episodic
memories, indicates a tendency in depression to display a negative bias in dissonance
reduction between negative chapters and positive events (Study four).
This thesis provides evidence that depression is linked to a negative bias in the higher-
order chapter level of autobiographical memory, and that due to dissonance reduction
processes, and the rehearsal of affectively congruent event-based representations, people with
depression may have reduced access to positive material which would be used in mood repair
and the creation of positive variation to their life-stories by drawing on specific events.Identity information in bonobo vocal communication: from sender to receiverKeenan, Sumirhttps://hdl.handle.net/10023/168102021-09-05T11:44:40Z2017-06-01T00:00:00ZIdentity information is vital for highly social species as it facilitates individual
recognition and allows for differentiation between social partners in many contexts,
such as dominance hierarchies, territorial defence, mating and parent-offspring
identification, and group cohesion and coordination. For many species vocalisations
can be the most effective communication channel in complex environments and over
long-distances and are encoded with the stable features of an individual’s voice.
Associations between these individual vocal signatures and accumulated social
knowledge about conspecifics can greatly increase an animal’s fitness, as it
facilitates adaptively constructive social decisions. This thesis investigates the
encoding and decoding of identity information in the vocal communication system of
the bonobo, Pan paniscus. We firstly investigated the stability of vocal signatures
across the five most common call types in the bonobo vocal repertoire. Results
showed that while all call types have the potential to code identity information, loud
calls used during times of high arousal and for distance communication have the
strongest individual vocal signatures. Following the first study, we investigated if
social familiarity and relatedness affect the acoustic features that code individual
information in the bark call type. Overall, we found strong evidence for vocal
convergence, and specifically, that individuals who are related and familiar,
independently from one another, are more vocally similar to one another than
unrelated and unfamiliar individuals. In a final study, we tested if bonobos are
capable of using the encoded identity information to recognise past group members
that they no longer live with. Through a series playback experiments we
demonstrated that bonobos are capable of recognising familiar individuals from
vocalisations alone even after years of separation. Collectively, the results of this
thesis show that the encoding and decoding of identity information in bonobo
vocalisations is a dynamic system, subject to modification through social processes
but robust enough to allow for individual recognition over time. In conclusion, these
studies contribute to a better understanding of the vocal communication system of a
non-human primate species with a unique and complex social network.
2017-06-01T00:00:00ZKeenan, SumirIdentity information is vital for highly social species as it facilitates individual
recognition and allows for differentiation between social partners in many contexts,
such as dominance hierarchies, territorial defence, mating and parent-offspring
identification, and group cohesion and coordination. For many species vocalisations
can be the most effective communication channel in complex environments and over
long-distances and are encoded with the stable features of an individual’s voice.
Associations between these individual vocal signatures and accumulated social
knowledge about conspecifics can greatly increase an animal’s fitness, as it
facilitates adaptively constructive social decisions. This thesis investigates the
encoding and decoding of identity information in the vocal communication system of
the bonobo, Pan paniscus. We firstly investigated the stability of vocal signatures
across the five most common call types in the bonobo vocal repertoire. Results
showed that while all call types have the potential to code identity information, loud
calls used during times of high arousal and for distance communication have the
strongest individual vocal signatures. Following the first study, we investigated if
social familiarity and relatedness affect the acoustic features that code individual
information in the bark call type. Overall, we found strong evidence for vocal
convergence, and specifically, that individuals who are related and familiar,
independently from one another, are more vocally similar to one another than
unrelated and unfamiliar individuals. In a final study, we tested if bonobos are
capable of using the encoded identity information to recognise past group members
that they no longer live with. Through a series playback experiments we
demonstrated that bonobos are capable of recognising familiar individuals from
vocalisations alone even after years of separation. Collectively, the results of this
thesis show that the encoding and decoding of identity information in bonobo
vocalisations is a dynamic system, subject to modification through social processes
but robust enough to allow for individual recognition over time. In conclusion, these
studies contribute to a better understanding of the vocal communication system of a
non-human primate species with a unique and complex social network.Title redactedDickerson, Katherine Leahhttps://hdl.handle.net/10023/168082019-09-25T13:31:11Z2017-06-20T00:00:00Z2017-06-20T00:00:00ZDickerson, Katherine LeahCourtship communication in the wild chimpanzees of Budongo, UgandaFallon, Brittanyhttps://hdl.handle.net/10023/167202021-10-06T02:07:39Z2017-04-24T00:00:00ZThis thesis examines wild chimpanzee mating behaviour, and considers in particular
the role of communication during mating. Previous studies have focused on compiling
behavioural ethograms, or on a small subset of courtship signals. More generally, research on
chimpanzee sexual behaviour has rarely looked at intentional communication, but instead
focused on a handful of courtship tactics, such as male long-term aggression or female
proceptive behaviour, despite every indication across great ape species that intentional
communication is important in courtship. On these grounds, I undertook an examination of
both male and female communication in the Sonso chimpanzee community in the Budongo
forest, Uganda.
The chapters comprising this thesis examine female copulation calling, male gestural
displays during opportunistic mating, male gestural displays during consortship, and the role
of female preferences on male courtship displays. Parous and nulliparous females have
different calling strategies based on high-ranking male audience, copulation duration, and
level of female competition. Males use a small subset of their gestural repertoire to solicit for
copulation, concentrating the majority of gesturing in 5 gesture types. Gestures were
successful for both high- and low-ranking males, although high-ranking males employed
more agonistic gestures than low-ranking males. All males showed high rates of persistence
following failure, especially during consortship. Overall, the likelihood of copulation was not
influenced by traditional courtship factors such as vigour, but rather was dependent on
effective use of gestures.
My research shows that both male and female chimpanzees use communication
tactically during courtship: for females, this is evidenced by differing copulation call
strategies in parous and nulliparous females. For males, social status plays less of a role than
persistence for achieving copulation, although high-ranking males do use coercive gestures
more frequently. Overall, I show that communication is an effective tool for answering
questions about mating strategies in chimpanzees.
2017-04-24T00:00:00ZFallon, BrittanyThis thesis examines wild chimpanzee mating behaviour, and considers in particular
the role of communication during mating. Previous studies have focused on compiling
behavioural ethograms, or on a small subset of courtship signals. More generally, research on
chimpanzee sexual behaviour has rarely looked at intentional communication, but instead
focused on a handful of courtship tactics, such as male long-term aggression or female
proceptive behaviour, despite every indication across great ape species that intentional
communication is important in courtship. On these grounds, I undertook an examination of
both male and female communication in the Sonso chimpanzee community in the Budongo
forest, Uganda.
The chapters comprising this thesis examine female copulation calling, male gestural
displays during opportunistic mating, male gestural displays during consortship, and the role
of female preferences on male courtship displays. Parous and nulliparous females have
different calling strategies based on high-ranking male audience, copulation duration, and
level of female competition. Males use a small subset of their gestural repertoire to solicit for
copulation, concentrating the majority of gesturing in 5 gesture types. Gestures were
successful for both high- and low-ranking males, although high-ranking males employed
more agonistic gestures than low-ranking males. All males showed high rates of persistence
following failure, especially during consortship. Overall, the likelihood of copulation was not
influenced by traditional courtship factors such as vigour, but rather was dependent on
effective use of gestures.
My research shows that both male and female chimpanzees use communication
tactically during courtship: for females, this is evidenced by differing copulation call
strategies in parous and nulliparous females. For males, social status plays less of a role than
persistence for achieving copulation, although high-ranking males do use coercive gestures
more frequently. Overall, I show that communication is an effective tool for answering
questions about mating strategies in chimpanzees.Carotenoid colour as a cue to health in human skinHenderson, Audrey Joanhttps://hdl.handle.net/10023/166702019-06-21T02:05:32Z2017-01-04T00:00:00ZCarotenoids are red-yellow plant based pigments. When consumed, they contribute to human
skin yellowness which in turn is perceived as healthy and attractive looking. In many non-primate species, carotenoids colour sexually selected ornaments, signalling health. This thesis
explores the relationship between skin yellowness and aspects of human health to test the
hypothesis that carotenoid colouration of skin acts as a cue to health beyond diet.
Chapter 2 presents a demonstration that a modest change in carotenoid intake can lead to a
favourable change in appearance. Chapter 3 investigates the relationship between skin
yellowness and a number of health related risk factors. Findings show that that psychological
stress varies with skin yellowness (independent of fruit and vegetable intake) both between
and within participants. Chapter 4 investigates the relationship between prior symptoms of
infectious illness (e.g. cold and flus); finding that symptoms experienced during the prior
eight weeks are related to skin yellowness between subjects and also within (marginally).
More recent symptoms of illness (i.e. the prior week) were not reflected in skin yellowness.
The final empirical chapter explores skin colour and plasma carotenoid changes with
experimentally induced sickness. Plasma carotenoids were found to reflect baseline skin
yellowness and showed a reduction in response to sickness but this reduction was not
reflected in skin yellowness. Skin colour did change in a manner consistent with changes in
blood perfusion and oxygenation status. A follow-up perceptual study confirmed that this
change can reliably inform judgements of health.
Taken together, findings suggest that skin yellowness is related to aspects of health beyond
diet (i.e. psychological stress and prior illness) on a timescale of weeks but not days; likely
reflecting the time taken for carotenoids to reach the skin. Theoretically, findings support the
hypothesis that carotenoid colouration of human skin is a cue to health.
2017-01-04T00:00:00ZHenderson, Audrey JoanCarotenoids are red-yellow plant based pigments. When consumed, they contribute to human
skin yellowness which in turn is perceived as healthy and attractive looking. In many non-primate species, carotenoids colour sexually selected ornaments, signalling health. This thesis
explores the relationship between skin yellowness and aspects of human health to test the
hypothesis that carotenoid colouration of skin acts as a cue to health beyond diet.
Chapter 2 presents a demonstration that a modest change in carotenoid intake can lead to a
favourable change in appearance. Chapter 3 investigates the relationship between skin
yellowness and a number of health related risk factors. Findings show that that psychological
stress varies with skin yellowness (independent of fruit and vegetable intake) both between
and within participants. Chapter 4 investigates the relationship between prior symptoms of
infectious illness (e.g. cold and flus); finding that symptoms experienced during the prior
eight weeks are related to skin yellowness between subjects and also within (marginally).
More recent symptoms of illness (i.e. the prior week) were not reflected in skin yellowness.
The final empirical chapter explores skin colour and plasma carotenoid changes with
experimentally induced sickness. Plasma carotenoids were found to reflect baseline skin
yellowness and showed a reduction in response to sickness but this reduction was not
reflected in skin yellowness. Skin colour did change in a manner consistent with changes in
blood perfusion and oxygenation status. A follow-up perceptual study confirmed that this
change can reliably inform judgements of health.
Taken together, findings suggest that skin yellowness is related to aspects of health beyond
diet (i.e. psychological stress and prior illness) on a timescale of weeks but not days; likely
reflecting the time taken for carotenoids to reach the skin. Theoretically, findings support the
hypothesis that carotenoid colouration of human skin is a cue to health.Title redactedJackson, Scott Luther Jameshttps://hdl.handle.net/10023/166452019-07-01T14:57:31Z2016-03-30T00:00:00Z2016-03-30T00:00:00ZJackson, Scott Luther JamesExploring how object shape and binocular vision interact to make or break camouflageCammack, Philiphttps://hdl.handle.net/10023/166242022-08-29T13:49:57Z2017-06-20T00:00:00ZDepth perception is a major component of 3D vision. There are many cues to depth; one
particularly sensitive aspect is the vivid perception of depth created from having eyes with
overlapping visual fields (binocular vision). As the eyes are located at different points in
space, they see different views of the scene – these slight differences (called binocular
disparity) can be used to obtain depth information. However, extracting depth from
disparity requires complex visual processing. So why use binocular vision?
Julesz (1971) proposed an explanation – camouflaged animals can fool the perception of
some cues to 3D shape, but camouflage is ineffective against binocular vision. We would
expect that animals with binocular vision could see the 3D shape of animals, despite their
camouflage. Whilst commonly accepted, this hypothesis has not been tested in detail. In
this thesis, we present experiments designed to establish how depth from binocular vision
interacts with camouflage and object shape. Two main questions were addressed:
First, we explored how the visual system represented depth information about 3D objects
from binocular disparity. Objects with smooth depth edges (hill-shaped) were perceived
with less depth than sharper edged objects. A computational model that segregated the
object, then averaged the disparity over the segregated region emulated human
performance. Finally, we found that disparity and luminance cues interacted to alter
perceived depth.
Secondly, we investigated if binocular vision could overcome camouflage. We found that
camouflaged objects defined by luminance were detected faster when also defined by
depth from disparity, thus reduces the effect of camouflage. Smooth objects were detected
slower than sharp objects: an effect that was replicated in the real world, suggesting a
camouflage technique to counter binocular vision.
In summary, binocular vision is useful because it can detect camouflaged objects. However,
smoother shapes take longer to spot, forming binocular (or stereoscopic) camouflage.
2017-06-20T00:00:00ZCammack, PhilipDepth perception is a major component of 3D vision. There are many cues to depth; one
particularly sensitive aspect is the vivid perception of depth created from having eyes with
overlapping visual fields (binocular vision). As the eyes are located at different points in
space, they see different views of the scene – these slight differences (called binocular
disparity) can be used to obtain depth information. However, extracting depth from
disparity requires complex visual processing. So why use binocular vision?
Julesz (1971) proposed an explanation – camouflaged animals can fool the perception of
some cues to 3D shape, but camouflage is ineffective against binocular vision. We would
expect that animals with binocular vision could see the 3D shape of animals, despite their
camouflage. Whilst commonly accepted, this hypothesis has not been tested in detail. In
this thesis, we present experiments designed to establish how depth from binocular vision
interacts with camouflage and object shape. Two main questions were addressed:
First, we explored how the visual system represented depth information about 3D objects
from binocular disparity. Objects with smooth depth edges (hill-shaped) were perceived
with less depth than sharper edged objects. A computational model that segregated the
object, then averaged the disparity over the segregated region emulated human
performance. Finally, we found that disparity and luminance cues interacted to alter
perceived depth.
Secondly, we investigated if binocular vision could overcome camouflage. We found that
camouflaged objects defined by luminance were detected faster when also defined by
depth from disparity, thus reduces the effect of camouflage. Smooth objects were detected
slower than sharp objects: an effect that was replicated in the real world, suggesting a
camouflage technique to counter binocular vision.
In summary, binocular vision is useful because it can detect camouflaged objects. However,
smoother shapes take longer to spot, forming binocular (or stereoscopic) camouflage.Provide all the details that you can remember : assessing the quantity and quality of autobiographical retrievalLucaciu, Irina-Mariahttps://hdl.handle.net/10023/163852019-04-01T10:40:42Z2018-12-06T00:00:00ZPeople asked to recall the memory of an event during testimony are encouraged to prioritize both quantity and quality – "the whole truth and nothing but the truth". Extensive research has shown that people can provide detailed, confident accounts that nevertheless prove to be inaccurate (Loftus, 1996). However, the question remains of how pressuring people to give confident and elaborate accounts of their memories subsequently changes these accounts. We conducted an experiment in which 51 participants provided accounts of autobiographical events and film plots (control condition), and later re-told these accounts under the instruction to retrieve more information. We measured the effects of task demands on the quantity (number of words and number of facts) and quality (confidence ratings) of information retrieved, as well as on the affective and cognitive language used during each account. Task demands at re-telling led to participants providing a greater amount of information, with their likelihood of doing so and their confidence in these newly communicated memory details linked to rumination tendencies and mood. These findings give insights into the cognitive processing of autobiographical memories, and provide a better understanding of the factors affecting eyewitness testimony.
2018-12-06T00:00:00ZLucaciu, Irina-MariaPeople asked to recall the memory of an event during testimony are encouraged to prioritize both quantity and quality – "the whole truth and nothing but the truth". Extensive research has shown that people can provide detailed, confident accounts that nevertheless prove to be inaccurate (Loftus, 1996). However, the question remains of how pressuring people to give confident and elaborate accounts of their memories subsequently changes these accounts. We conducted an experiment in which 51 participants provided accounts of autobiographical events and film plots (control condition), and later re-told these accounts under the instruction to retrieve more information. We measured the effects of task demands on the quantity (number of words and number of facts) and quality (confidence ratings) of information retrieved, as well as on the affective and cognitive language used during each account. Task demands at re-telling led to participants providing a greater amount of information, with their likelihood of doing so and their confidence in these newly communicated memory details linked to rumination tendencies and mood. These findings give insights into the cognitive processing of autobiographical memories, and provide a better understanding of the factors affecting eyewitness testimony.An investigation into the benefits of musical training on cognitive control and emotional processing abilitiesFisher, Nina K.https://hdl.handle.net/10023/163812023-03-21T09:54:01Z2018-03-09T00:00:00ZEvidence suggests that engagement in musical activity may confer cognitive
control advantages though it is not clear why this may be. Here it was explored why such
advantages may be observed, exploring a potential underlying mechanism which may
be responsible for these enhancements using EEG, behavioural, and self-rating methods.
Chapters two and three were unable to replicate previous research which report an
association between musical training and enhanced cognitive control, though the results
suggest that musical training may heighten emotional responses to errors. Considering
that musical performance and training involves active, frequent, and repeated
engagement with emotional material, chapters four and five aimed to investigate
whether musical training can lead to enhancements in emotional processing abilities
using a variety of questionnaires and behavioural tasks. Chapter four found significant
associations between musical training and enhanced emotional sound recognition
accuracy and empathic abilities, although these effects were not replicated in the
subsequent chapter, which detected only similar numerical trends. Chapter six was
carried out to investigate if the potential association between musical training and
enhanced empathy could be observed in a larger and more diverse sample.
Furthermore, activities which use similar higher order processes were included to
investigate if they could confer the same potential advantages. This study again failed
to find a relationship between musical training and enhanced empathy, though dance
and sport were significant predictors of higher empathy levels. Considering that all
studies reported in this thesis are cross-sectional, these fragile results could be partially
due to individual differences between groups and studies. In sum, the results of this
thesis provide limited evidence that musical training may enhance specific emotional
processing abilities and affective responses to errors which may lead to both enhanced
cognitive control, and improved social awareness and interactions with others.
2018-03-09T00:00:00ZFisher, Nina K.Evidence suggests that engagement in musical activity may confer cognitive
control advantages though it is not clear why this may be. Here it was explored why such
advantages may be observed, exploring a potential underlying mechanism which may
be responsible for these enhancements using EEG, behavioural, and self-rating methods.
Chapters two and three were unable to replicate previous research which report an
association between musical training and enhanced cognitive control, though the results
suggest that musical training may heighten emotional responses to errors. Considering
that musical performance and training involves active, frequent, and repeated
engagement with emotional material, chapters four and five aimed to investigate
whether musical training can lead to enhancements in emotional processing abilities
using a variety of questionnaires and behavioural tasks. Chapter four found significant
associations between musical training and enhanced emotional sound recognition
accuracy and empathic abilities, although these effects were not replicated in the
subsequent chapter, which detected only similar numerical trends. Chapter six was
carried out to investigate if the potential association between musical training and
enhanced empathy could be observed in a larger and more diverse sample.
Furthermore, activities which use similar higher order processes were included to
investigate if they could confer the same potential advantages. This study again failed
to find a relationship between musical training and enhanced empathy, though dance
and sport were significant predictors of higher empathy levels. Considering that all
studies reported in this thesis are cross-sectional, these fragile results could be partially
due to individual differences between groups and studies. In sum, the results of this
thesis provide limited evidence that musical training may enhance specific emotional
processing abilities and affective responses to errors which may lead to both enhanced
cognitive control, and improved social awareness and interactions with others.Behavioural examination of the role of the thalamic reticular nucleus in attentionStanislaus-Carter, Rudihttps://hdl.handle.net/10023/162982019-04-01T10:42:13Z2017-06-20T00:00:00ZThe ability to selectively attend to aspects of the environment which signal opportunity or danger, while marginalising irrelevant stimuli is critical to an animal’s survival. With finite cognitive resources, the brain must dedicate resources to only those stimuli that are biologically significant. Incoming thalamic information must therefore be filtered. The thalamic reticular nucleus has long been considered critically involved in modulating thalamic sensory processing. Sharing connections with both the thalamus and cortex, it is ideally located to modulate the transfer of pertinent incoming sensory information.
This thesis sought to determine the functional role of the thalamic reticular nucleus in attentional processes by combining lesion techniques and well established behavioural paradigms.
Chapter 3 examined the role of visual thalamic reticular nucleus lesions on performance in a two-alternative forced choice reaction time task when auditory distractors were presented. No effect of the lesion was found. Chapter 4 examined excitotoxic lesions of thalamic retlcular nucleus on performance in the 7-stage attentional set shifting task. No effect of lesion on performance was found. Chapter 5 examined mediodorsal thalamus and rostral thalamic reticular nucleus lesions on performance in the attentional set shifting task. Despite strong connectivity with prefrontal regions known to be involved in this task, there was no effect of either lesion. Finally, chapter 6 examined the effects of reducing dopamine input into the thalamic reticular nucleus on a two alternative forced choice reaction time task. Following bilateral lesions the animals were impaired in the re-orientation of attention – suggesting a critical role for both the thalamic reticular nucleus and dopamine in attentional processes. Taken together, these results suggest that while the thalamic reticular nucleus is involved in attention, it is not involved in every aspect.
2017-06-20T00:00:00ZStanislaus-Carter, RudiThe ability to selectively attend to aspects of the environment which signal opportunity or danger, while marginalising irrelevant stimuli is critical to an animal’s survival. With finite cognitive resources, the brain must dedicate resources to only those stimuli that are biologically significant. Incoming thalamic information must therefore be filtered. The thalamic reticular nucleus has long been considered critically involved in modulating thalamic sensory processing. Sharing connections with both the thalamus and cortex, it is ideally located to modulate the transfer of pertinent incoming sensory information.
This thesis sought to determine the functional role of the thalamic reticular nucleus in attentional processes by combining lesion techniques and well established behavioural paradigms.
Chapter 3 examined the role of visual thalamic reticular nucleus lesions on performance in a two-alternative forced choice reaction time task when auditory distractors were presented. No effect of the lesion was found. Chapter 4 examined excitotoxic lesions of thalamic retlcular nucleus on performance in the 7-stage attentional set shifting task. No effect of lesion on performance was found. Chapter 5 examined mediodorsal thalamus and rostral thalamic reticular nucleus lesions on performance in the attentional set shifting task. Despite strong connectivity with prefrontal regions known to be involved in this task, there was no effect of either lesion. Finally, chapter 6 examined the effects of reducing dopamine input into the thalamic reticular nucleus on a two alternative forced choice reaction time task. Following bilateral lesions the animals were impaired in the re-orientation of attention – suggesting a critical role for both the thalamic reticular nucleus and dopamine in attentional processes. Taken together, these results suggest that while the thalamic reticular nucleus is involved in attention, it is not involved in every aspect.The context of behavioural flexibility in chimpanzees (Pan troglodytes) : implications for the evolution of cumulative cultureDavis, Sarah Jaynehttps://hdl.handle.net/10023/162972019-04-01T10:42:19Z2017-06-20T00:00:00ZCumulative culture is rare, if not altogether absent in non-human species. At the foundation of
cumulative learning is the ability to flexibly modify, relinquish or build upon prior behaviours to
make them more productive or efficient. Within the primate literature, a failure to optimise
solutions in this way is often proposed to derive from low-fidelity copying of witnessed
behaviours, sub-optimal social learning heuristics, or a lack of relevant socio-cognitive
adaptations. However, humans can also be markedly inflexible in their behaviours, perseverating
with, or becoming fixated on outdated or inappropriate responses. Humans show differential
patterns of flexibility as a function of cognitive load, exhibiting difficulties with inhibiting suboptimal
behaviours when there are high demands on working memory. Here I present a series
of studies on captive chimpanzees which show that not only is inhibitory control compromised
in chimpanzees, but indicate ape behavioural conservatism may be underlain by similar
constraints as in humans; chimpanzees show relatively little conservatism when behavioural
optimisation involves the inhibition of a well-established but simple solution, or the addition of
a simple modification to a well-established but complex solution. In contrast, when behavioural
optimisation involves the inhibition of a well-established but complex solution, and especially
when the alternative solution is also complex, chimpanzees show evidence of behavioural
conservatism. I propose that conservatism is linked to behavioural complexity, potentially
mediated by cognitive resource availability, and may be an important factor in the evolution of
cumulative culture.
2017-06-20T00:00:00ZDavis, Sarah JayneCumulative culture is rare, if not altogether absent in non-human species. At the foundation of
cumulative learning is the ability to flexibly modify, relinquish or build upon prior behaviours to
make them more productive or efficient. Within the primate literature, a failure to optimise
solutions in this way is often proposed to derive from low-fidelity copying of witnessed
behaviours, sub-optimal social learning heuristics, or a lack of relevant socio-cognitive
adaptations. However, humans can also be markedly inflexible in their behaviours, perseverating
with, or becoming fixated on outdated or inappropriate responses. Humans show differential
patterns of flexibility as a function of cognitive load, exhibiting difficulties with inhibiting suboptimal
behaviours when there are high demands on working memory. Here I present a series
of studies on captive chimpanzees which show that not only is inhibitory control compromised
in chimpanzees, but indicate ape behavioural conservatism may be underlain by similar
constraints as in humans; chimpanzees show relatively little conservatism when behavioural
optimisation involves the inhibition of a well-established but simple solution, or the addition of
a simple modification to a well-established but complex solution. In contrast, when behavioural
optimisation involves the inhibition of a well-established but complex solution, and especially
when the alternative solution is also complex, chimpanzees show evidence of behavioural
conservatism. I propose that conservatism is linked to behavioural complexity, potentially
mediated by cognitive resource availability, and may be an important factor in the evolution of
cumulative culture.Cholinergic modulation of spinal motoneurons and locomotor control networks in miceNascimento, Filipehttps://hdl.handle.net/10023/161412019-04-01T10:40:22Z2018-12-06T00:00:00ZLocomotion is an innate behaviour that is controlled by different areas of the central nervous system, which allow for effectiveness of movement. The spinal cord is an important centre involved in the generation and maintenance of rhythmic patterns of locomotor activity such as walking and running. Interneurons throughout the ventral horn of the spinal cord form the locomotor central pattern generator (CPG) circuit, which produces rhythmic activity responsible for hindlimb movement. Motoneurons within the lumbar region of the spinal cord innervate the leg muscles to convey rhythmic CPG output to drive appropriate muscle contractions. Intrinsic modulators, such as acetylcholine acting via M2 and M3 muscarinic receptors, regulate CPG circuitry to allow for flexibility of motor output. Using electrophysiology and genetic techniques, this work characterized the receptors involved in cholinergic modulation of locomotor networks and the role and mechanism of action of a subpopulation of genetically identified cholinergic interneurons in the lumbar region of the neonatal mouse spinal cord.
Firstly, the effects of M2 and M3 muscarinic receptors on the output of the lumbar locomotor network were characterised. Experiments in which fictive locomotor output was recorded from the ventral roots of isolated spinal cord preparations revealed that M3 muscarinic receptors are important in stabilizing the locomotor rhythm while M2 muscarinic receptor activation seems to increase the irregularity of the locomotor frequency whilst increasing the strength of the motor output. This work then explored the cellular mechanisms through which M2 and M3 muscarinic receptors modulate motoneuron output. M2 and M3 receptor activation exhibited contrasting effects on motoneuron function suggesting that there is a fine balance between the activation of these two receptor subtypes. M2 receptor activation induces an outward current and decreases synaptic drive to motoneurons while M3 receptors are responsible for an inward current and increase in synaptic inputs to motoneurons. Despite the different effects of M2 and M3 receptor activation on synaptic drive and subthreshold properties of MNs, both M2 and M3 receptors are required for muscarine-induced increase in motoneuron output. CPG networks therefore appear to be subject to balanced cholinergic modulation mediated by M2 and M3 receptors, with the M2 subtype also being important for regulating the intensity of motor output.
Next, using Designer Receptor Exclusively Activated by Designer Drug (DREADD) technology, the impact of the activation or inhibition of a genetically identified group of cholinergic spinal interneurons that express the Paired-like homeodomain 2 (Pitx2) transcription factor was explored. Stimulation of these interneurons increased motoneuron output through the activation of M2 muscarinic receptors and subsequent modulation of Kv2.1 channels. Inhibition of Pitx2⁺ interneurons during fictive locomotion decreased the amplitude of locomotor bursting. Genetic ablation of these cells confirmed that Pitx2⁺ interneurons increase the strength of locomotor output by activating M2 muscarinic receptors.
Overall, this work provides new insights into the receptors and mechanisms involved in intraspinal cholinergic modulation. Furthermore, this study provides direct evidence of the mechanism through which Pitx2⁺ interneurons regulate motor output. This work is not only important for advancing understanding of locomotor networks that control hindlimb locomotion, but also for dysfunction and diseases where the cholinergic system is impaired such as Spinal Cord Injury and Amyotrophic Lateral Sclerosis.
2018-12-06T00:00:00ZNascimento, FilipeLocomotion is an innate behaviour that is controlled by different areas of the central nervous system, which allow for effectiveness of movement. The spinal cord is an important centre involved in the generation and maintenance of rhythmic patterns of locomotor activity such as walking and running. Interneurons throughout the ventral horn of the spinal cord form the locomotor central pattern generator (CPG) circuit, which produces rhythmic activity responsible for hindlimb movement. Motoneurons within the lumbar region of the spinal cord innervate the leg muscles to convey rhythmic CPG output to drive appropriate muscle contractions. Intrinsic modulators, such as acetylcholine acting via M2 and M3 muscarinic receptors, regulate CPG circuitry to allow for flexibility of motor output. Using electrophysiology and genetic techniques, this work characterized the receptors involved in cholinergic modulation of locomotor networks and the role and mechanism of action of a subpopulation of genetically identified cholinergic interneurons in the lumbar region of the neonatal mouse spinal cord.
Firstly, the effects of M2 and M3 muscarinic receptors on the output of the lumbar locomotor network were characterised. Experiments in which fictive locomotor output was recorded from the ventral roots of isolated spinal cord preparations revealed that M3 muscarinic receptors are important in stabilizing the locomotor rhythm while M2 muscarinic receptor activation seems to increase the irregularity of the locomotor frequency whilst increasing the strength of the motor output. This work then explored the cellular mechanisms through which M2 and M3 muscarinic receptors modulate motoneuron output. M2 and M3 receptor activation exhibited contrasting effects on motoneuron function suggesting that there is a fine balance between the activation of these two receptor subtypes. M2 receptor activation induces an outward current and decreases synaptic drive to motoneurons while M3 receptors are responsible for an inward current and increase in synaptic inputs to motoneurons. Despite the different effects of M2 and M3 receptor activation on synaptic drive and subthreshold properties of MNs, both M2 and M3 receptors are required for muscarine-induced increase in motoneuron output. CPG networks therefore appear to be subject to balanced cholinergic modulation mediated by M2 and M3 receptors, with the M2 subtype also being important for regulating the intensity of motor output.
Next, using Designer Receptor Exclusively Activated by Designer Drug (DREADD) technology, the impact of the activation or inhibition of a genetically identified group of cholinergic spinal interneurons that express the Paired-like homeodomain 2 (Pitx2) transcription factor was explored. Stimulation of these interneurons increased motoneuron output through the activation of M2 muscarinic receptors and subsequent modulation of Kv2.1 channels. Inhibition of Pitx2⁺ interneurons during fictive locomotion decreased the amplitude of locomotor bursting. Genetic ablation of these cells confirmed that Pitx2⁺ interneurons increase the strength of locomotor output by activating M2 muscarinic receptors.
Overall, this work provides new insights into the receptors and mechanisms involved in intraspinal cholinergic modulation. Furthermore, this study provides direct evidence of the mechanism through which Pitx2⁺ interneurons regulate motor output. This work is not only important for advancing understanding of locomotor networks that control hindlimb locomotion, but also for dysfunction and diseases where the cholinergic system is impaired such as Spinal Cord Injury and Amyotrophic Lateral Sclerosis.Monkeys (Sapajus apella and Macaca tonkeana) and great apes (Gorilla gorilla, Pongo pygmaeus, Pongo abelii, Pan paniscus and Pan troglodytes) play for the highest bidBroihanne, M. -H.Romain, A.Call, JosepThierry, B.Wascher, C. A. F.De Marco, A.Verrier, D.Dufour, V.https://hdl.handle.net/10023/160922024-02-20T00:42:24Z2018-12-27T00:00:00ZMany studies investigate the decisions made by animals by focussing on their individual attitudes towards risk, i.e., risk seeking, risk neutrality or risk aversion. However, little attention has been paid to how far individuals understand the different odds of outcomes. In a previous gambling task involving up to 18 different lotteries (Pelé et al., 2014), non-human primates used probabilities of gains and losses to make their decision. Although the use of complex mathematical calculation for decision-making seemed unlikely, we applied a gradual decrease in the chances to win throughout the experiment. This probably facilitated the extraction of information about odds. Here, we investigated whether individuals would still make efficient decisions if this facilitating factor was removed. To do so, we randomized the order of presentation of the 18 lotteries. Individuals from four ape and two monkey species were tested. Only capuchin monkeys differed in their gambling behaviour, playing even when there was nothing to win. Randomising the lottery presentation order leads all species to predominantly use a maximax heuristic in which individuals gamble as soon as there is at least one chance to win more than they already possess, whatever the risk. Most species also gambled more as the frequency of larger rewards increased. These results suggest the occurrence of optimistic behaviour. The maximax heuristic is sometimes observed in human managerial and financial decision-making, where risk is ignored for potential gains, however low they may be. Our results suggest a shared and strong propensity in primates to rely on heuristics whenever complexity in evaluation of outcome odds arises.
This work was supported by grants from the Agence Nationale de la Recherche (ANR-08-412 BLAN-0042-01) and the European Science Foundation (Compcog Exchange Grant N°3648).
2018-12-27T00:00:00ZBroihanne, M. -H.Romain, A.Call, JosepThierry, B.Wascher, C. A. F.De Marco, A.Verrier, D.Dufour, V.Many studies investigate the decisions made by animals by focussing on their individual attitudes towards risk, i.e., risk seeking, risk neutrality or risk aversion. However, little attention has been paid to how far individuals understand the different odds of outcomes. In a previous gambling task involving up to 18 different lotteries (Pelé et al., 2014), non-human primates used probabilities of gains and losses to make their decision. Although the use of complex mathematical calculation for decision-making seemed unlikely, we applied a gradual decrease in the chances to win throughout the experiment. This probably facilitated the extraction of information about odds. Here, we investigated whether individuals would still make efficient decisions if this facilitating factor was removed. To do so, we randomized the order of presentation of the 18 lotteries. Individuals from four ape and two monkey species were tested. Only capuchin monkeys differed in their gambling behaviour, playing even when there was nothing to win. Randomising the lottery presentation order leads all species to predominantly use a maximax heuristic in which individuals gamble as soon as there is at least one chance to win more than they already possess, whatever the risk. Most species also gambled more as the frequency of larger rewards increased. These results suggest the occurrence of optimistic behaviour. The maximax heuristic is sometimes observed in human managerial and financial decision-making, where risk is ignored for potential gains, however low they may be. Our results suggest a shared and strong propensity in primates to rely on heuristics whenever complexity in evaluation of outcome odds arises.Learning to focus and focusing to learn : more than a cortical trickDhawan, Sandeep Sonnyhttps://hdl.handle.net/10023/158832019-04-01T10:40:26Z2018-12-06T00:00:00ZThe consequence of many psychiatric and neurodegenerative disorders, such as Parkinson’s disease and schizophrenia, is an impairment in ‘executive functioning’; an umbrella term for several cognitive processes, including the focussing and shifting of attention and the inhibition of responding. The ability to form an ‘attentional set’ involves learning to discriminate qualities of a multidimensional cue, and to subsequently learn which quality is relevant, and therefore predictive of reward. According to recent research, the subthalamic nucleus (STN) and possibly the adjacent zona incerta (ZI) may mediate the formation of attentional set. Dysregulation of the STN as a result of Parkinson’s disease contributes to characteristic motor symptoms, and whilst deep-brain stimulation of this region may treat gross motor impairments, it may also impair cognition. The work in this thesis aimed to expand our understanding of the mechanisms of attentional set-formation, and the role of the STN in this process.
This thesis evaluates new methods for examining set-formation in the attentional set-shifting task; rather than inferring this behaviour solely from the cost of shifting set, modifications to the task design in Chapters 3 & 4 explored several hypotheses designed to exploit a deficit in this behaviour. Chapter 6 revealed that inhibition of this region with designer receptors leads to a disruption in attentional selectivity, which compromises the ability to form an attentional set. This manifested as an inability to parse relevant information from irrelevant, and instead, animals learned the stimuli holistically. The findings in this thesis also suggested that reversal and attentional shifting processes do not operate independently, but rather in a hierarchy, and that consequently, the STN is a region that may be crucial in selecting appropriate responses during associative learning that leads to the formation of an attentional set.
2018-12-06T00:00:00ZDhawan, Sandeep SonnyThe consequence of many psychiatric and neurodegenerative disorders, such as Parkinson’s disease and schizophrenia, is an impairment in ‘executive functioning’; an umbrella term for several cognitive processes, including the focussing and shifting of attention and the inhibition of responding. The ability to form an ‘attentional set’ involves learning to discriminate qualities of a multidimensional cue, and to subsequently learn which quality is relevant, and therefore predictive of reward. According to recent research, the subthalamic nucleus (STN) and possibly the adjacent zona incerta (ZI) may mediate the formation of attentional set. Dysregulation of the STN as a result of Parkinson’s disease contributes to characteristic motor symptoms, and whilst deep-brain stimulation of this region may treat gross motor impairments, it may also impair cognition. The work in this thesis aimed to expand our understanding of the mechanisms of attentional set-formation, and the role of the STN in this process.
This thesis evaluates new methods for examining set-formation in the attentional set-shifting task; rather than inferring this behaviour solely from the cost of shifting set, modifications to the task design in Chapters 3 & 4 explored several hypotheses designed to exploit a deficit in this behaviour. Chapter 6 revealed that inhibition of this region with designer receptors leads to a disruption in attentional selectivity, which compromises the ability to form an attentional set. This manifested as an inability to parse relevant information from irrelevant, and instead, animals learned the stimuli holistically. The findings in this thesis also suggested that reversal and attentional shifting processes do not operate independently, but rather in a hierarchy, and that consequently, the STN is a region that may be crucial in selecting appropriate responses during associative learning that leads to the formation of an attentional set.Eye movements and driving : insights into methodology, individual differences and trainingMackenzie, Andrew K.https://hdl.handle.net/10023/156902019-04-01T10:41:27Z2016-01-01T00:00:00ZDriving is a complex visuomotor task, and the study of eye movements can provide interesting
and detailed insights into driving behaviour. The aim of this thesis was to understand (a) what
methods are useful to assess driving behaviour, (b) the reasons we observe differences in eye
movements when driving, and (c) offer a possible visual training method. The first experiment
compared drivers’ eye movements and hazard perception performance in an active simulated
driving task and a passive video driving task. A number of differences were found, including
an extended horizontal and vertical visual search and faster response to the hazards in the video
task. It was concluded that when measuring driving behaviour in an active task, vision,
attention and action interact in a complex manner that is reflected in a specific pattern of eye
movements that is different to when driving behaviour is measured using typical video
paradigms. The second experiment investigated how cognitive functioning may influence eye
movement behaviour when driving. It was found that those with better cognitive functioning
exhibited more efficient eye movement behaviour than those with poorer cognitive functioning.
The third experiment compared the eye movement and driving behaviour of an older adult
population and a younger adult population. There were no differences in the eye movement
behaviour. However, the older adults drove significantly slower, suggesting attentional
compensation. The final experiment investigated the efficacy of using eye movement videos
as a visual training tool for novice drivers. It was found that novice drivers improved their
visual search strategy when driving after viewing videos of an expert driver’s eye movements.
The results of this thesis helps to provide insights into how the visual system is used for a
complex behaviour such as driving. It also furthers the understanding of what may contribute
to, and what may prevent, road accidents.;
2016-01-01T00:00:00ZMackenzie, Andrew K.Driving is a complex visuomotor task, and the study of eye movements can provide interesting
and detailed insights into driving behaviour. The aim of this thesis was to understand (a) what
methods are useful to assess driving behaviour, (b) the reasons we observe differences in eye
movements when driving, and (c) offer a possible visual training method. The first experiment
compared drivers’ eye movements and hazard perception performance in an active simulated
driving task and a passive video driving task. A number of differences were found, including
an extended horizontal and vertical visual search and faster response to the hazards in the video
task. It was concluded that when measuring driving behaviour in an active task, vision,
attention and action interact in a complex manner that is reflected in a specific pattern of eye
movements that is different to when driving behaviour is measured using typical video
paradigms. The second experiment investigated how cognitive functioning may influence eye
movement behaviour when driving. It was found that those with better cognitive functioning
exhibited more efficient eye movement behaviour than those with poorer cognitive functioning.
The third experiment compared the eye movement and driving behaviour of an older adult
population and a younger adult population. There were no differences in the eye movement
behaviour. However, the older adults drove significantly slower, suggesting attentional
compensation. The final experiment investigated the efficacy of using eye movement videos
as a visual training tool for novice drivers. It was found that novice drivers improved their
visual search strategy when driving after viewing videos of an expert driver’s eye movements.
The results of this thesis helps to provide insights into how the visual system is used for a
complex behaviour such as driving. It also furthers the understanding of what may contribute
to, and what may prevent, road accidents.
Title redactedSchapero, Melissahttps://hdl.handle.net/10023/156862019-09-30T11:40:26Z2016-01-01T00:00:00Z2016-01-01T00:00:00ZSchapero, MelissaInvestigating the link between intrusive memories and cognitive controlSayan, Stephaniehttps://hdl.handle.net/10023/156552019-04-01T10:41:49Z2016-01-01T00:00:00ZIntrusive memories are memories for negative autobiographical events that come to
mind without being deliberately recalled (Hackmann, Ehlers, Speckens, & Clark,
2004). Previous research has demonstrated that intrusive memories, and negative
reactions to intrusive memories, are an important feature of depression (Starr &
Moulds, 2006; Williams & Moulds, 2008b) and contribute to the maintenance of
depression longitudinally (Newby & Moulds, 2011c). It has also been established that
intrusive memory experience is related to individual differences in cognitive control,
specifically in proactive interference resolution (Verwoerd, Wessel, & de Jong, 2009;
Verwoerd, Wessel, de Jong, Nieuwenhuis, & Huntjens, 2011). The present thesis
aimed to extend upon these existing findings, using the Dual Mechanism of Control
theory, which distinguishes between proactive and reactive modes of control (Braver,
Gray, & Burgess, 2007). Furthermore, in view of some recent ambiguity of the
defining feature of an intrusive memory, as compared to a negative involuntary
memory more generally (Kvavilashvili, 2014; Moulds & Krans, 2015), another goal
of the thesis was to incorporate a wider focus of involuntary memories, rather than
focusing only on traditionally studied intrusive memories. Participants from the
student population and local community were tested. Overall, results provide some
evidence for a negative involuntary memory related deficit in proactive control, on
both a classic and an emotional version of the AX-Continuous Performance Task
(AX-CPT). Conversely, there was no link between intrusive or involuntary memory
experience and reactive control. A brief mindfulness and self-compassion based
intervention, designed to reduce negative reactions to intrusive memories, was also
tested. The intervention was successful in reducing intrusive-memory distress, and
recommendations for the future development of the intervention are presented.
2016-01-01T00:00:00ZSayan, StephanieIntrusive memories are memories for negative autobiographical events that come to
mind without being deliberately recalled (Hackmann, Ehlers, Speckens, & Clark,
2004). Previous research has demonstrated that intrusive memories, and negative
reactions to intrusive memories, are an important feature of depression (Starr &
Moulds, 2006; Williams & Moulds, 2008b) and contribute to the maintenance of
depression longitudinally (Newby & Moulds, 2011c). It has also been established that
intrusive memory experience is related to individual differences in cognitive control,
specifically in proactive interference resolution (Verwoerd, Wessel, & de Jong, 2009;
Verwoerd, Wessel, de Jong, Nieuwenhuis, & Huntjens, 2011). The present thesis
aimed to extend upon these existing findings, using the Dual Mechanism of Control
theory, which distinguishes between proactive and reactive modes of control (Braver,
Gray, & Burgess, 2007). Furthermore, in view of some recent ambiguity of the
defining feature of an intrusive memory, as compared to a negative involuntary
memory more generally (Kvavilashvili, 2014; Moulds & Krans, 2015), another goal
of the thesis was to incorporate a wider focus of involuntary memories, rather than
focusing only on traditionally studied intrusive memories. Participants from the
student population and local community were tested. Overall, results provide some
evidence for a negative involuntary memory related deficit in proactive control, on
both a classic and an emotional version of the AX-Continuous Performance Task
(AX-CPT). Conversely, there was no link between intrusive or involuntary memory
experience and reactive control. A brief mindfulness and self-compassion based
intervention, designed to reduce negative reactions to intrusive memories, was also
tested. The intervention was successful in reducing intrusive-memory distress, and
recommendations for the future development of the intervention are presented.An investigation of factors influencing the student experience at universityMiles, Paula Jeanhttps://hdl.handle.net/10023/156542023-10-17T02:05:58Z2018-01-01T00:00:00ZUniversity students are increasingly considered ‘consumers’, while universities are viewed as ‘service providers’. It is therefore imperative that higher education institutions explore and better understand factors influencing the student experience. This thesis investigates the impact that three elements of the university environment have on the student experience. Firstly, student and staff views of good academic practice were examined. Participants rated scenarios representing four areas of academic practice (aiding and abetting, multiple submission, contract cheating and plagiarism) as good practice, poor practice or misconduct. While scenarios at extreme ends of the academic practice continuum generated near-uniform responses, some scenarios lacked consensus between student and staff. The most contentious areas of academic practice were those involving help from peers. Disparity in opinions highlights the need for greater analysis and education to reach a shared understanding of academic practice across the university. Secondly, well-being levels of first year undergraduates were measured across an academic year to identify periods when students might benefit from additional support. Well-being was poorer at the end, compared to the beginning, of the academic season. In addition, students who completed high school in North America experienced poorer well-being compared to their UK and European peers. Finally the effectiveness of traditional and interactive teaching approaches were recorded following both teaching styles. This held true for experienced and novice teachers. Irrespective of teaching style, female students were less satisfied with sessions and less confident when completing final statistical analyses compared to males. Overall, this work has advanced understanding of how all three keys factors influence the student experience and has highlighted areas where improvements can be made. Importantly, this study demonstrates methodologies for conducting and scientifically rigorous research within an educational setting.
2018-01-01T00:00:00ZMiles, Paula JeanUniversity students are increasingly considered ‘consumers’, while universities are viewed as ‘service providers’. It is therefore imperative that higher education institutions explore and better understand factors influencing the student experience. This thesis investigates the impact that three elements of the university environment have on the student experience. Firstly, student and staff views of good academic practice were examined. Participants rated scenarios representing four areas of academic practice (aiding and abetting, multiple submission, contract cheating and plagiarism) as good practice, poor practice or misconduct. While scenarios at extreme ends of the academic practice continuum generated near-uniform responses, some scenarios lacked consensus between student and staff. The most contentious areas of academic practice were those involving help from peers. Disparity in opinions highlights the need for greater analysis and education to reach a shared understanding of academic practice across the university. Secondly, well-being levels of first year undergraduates were measured across an academic year to identify periods when students might benefit from additional support. Well-being was poorer at the end, compared to the beginning, of the academic season. In addition, students who completed high school in North America experienced poorer well-being compared to their UK and European peers. Finally the effectiveness of traditional and interactive teaching approaches were recorded following both teaching styles. This held true for experienced and novice teachers. Irrespective of teaching style, female students were less satisfied with sessions and less confident when completing final statistical analyses compared to males. Overall, this work has advanced understanding of how all three keys factors influence the student experience and has highlighted areas where improvements can be made. Importantly, this study demonstrates methodologies for conducting and scientifically rigorous research within an educational setting.Vocal combinations in guenon communicationCoye, Camillehttps://hdl.handle.net/10023/156502019-04-01T10:40:24Z2016-01-01T00:00:00ZIt is generally accepted that comparative studies on animal communication can provide insights into the
coevolution of social life, vocal communication, cognitive capacities and notably the emergence of
some human language features. Recent studies suggested that non-human primates possess
combinatorial abilities that may allow a diversification of vocal repertoires or a richer communication
in spite of limited articulatory capacities. However, the functions of combined calls and the information
that receivers can extract remain poorly understood. This thesis investigated call combination systems
in two species of guenons: Campbell’s monkey (Cercopithecus Campbelli) and Diana monkey
(Cercopithecus Diana). Firstly, I studied the combinatorial structure and relevance to receivers of
combined calls in of both species using playback experiments. Results confirmed the presence of a
suffixation mechanism reducing the emergency of danger signaled by calls of male Campbell’s
monkeys. Also, they showed that combined calls of females Diana monkeys convey linearly
information via their two units, which signal respectively caller’s emotional state and identity.
Secondly, focusing on the context associated with the emission of simple and combined female
Campbell’s monkey calls, results revealed flexible use of combination reflecting the immediate need to
remain cryptic (i.e. simple calls) or to signal caller’s identity (i.e. combined calls). Finally, I compared
females’ communication systems of both species to identify their similarities and differences. As
predicted by their close phylogenetic relatedness, their repertoires are mostly based on homologous
structures. However, the females differ strongly in their use of those structures. In particular, the great
number of calls combined by Diana monkeys increases considerably their vocal repertoire compared to
Campbell’s monkeys. Given that the combinations are non-random, meaningful to receivers and used
flexibly with the context, I propose a parallel with a rudimentary form of semantic morphosyntax and
discuss more generally the possible existence of similar capacities in other non-human animals.
2016-01-01T00:00:00ZCoye, CamilleIt is generally accepted that comparative studies on animal communication can provide insights into the
coevolution of social life, vocal communication, cognitive capacities and notably the emergence of
some human language features. Recent studies suggested that non-human primates possess
combinatorial abilities that may allow a diversification of vocal repertoires or a richer communication
in spite of limited articulatory capacities. However, the functions of combined calls and the information
that receivers can extract remain poorly understood. This thesis investigated call combination systems
in two species of guenons: Campbell’s monkey (Cercopithecus Campbelli) and Diana monkey
(Cercopithecus Diana). Firstly, I studied the combinatorial structure and relevance to receivers of
combined calls in of both species using playback experiments. Results confirmed the presence of a
suffixation mechanism reducing the emergency of danger signaled by calls of male Campbell’s
monkeys. Also, they showed that combined calls of females Diana monkeys convey linearly
information via their two units, which signal respectively caller’s emotional state and identity.
Secondly, focusing on the context associated with the emission of simple and combined female
Campbell’s monkey calls, results revealed flexible use of combination reflecting the immediate need to
remain cryptic (i.e. simple calls) or to signal caller’s identity (i.e. combined calls). Finally, I compared
females’ communication systems of both species to identify their similarities and differences. As
predicted by their close phylogenetic relatedness, their repertoires are mostly based on homologous
structures. However, the females differ strongly in their use of those structures. In particular, the great
number of calls combined by Diana monkeys increases considerably their vocal repertoire compared to
Campbell’s monkeys. Given that the combinations are non-random, meaningful to receivers and used
flexibly with the context, I propose a parallel with a rudimentary form of semantic morphosyntax and
discuss more generally the possible existence of similar capacities in other non-human animals.Religiosity and prejudice in a Western and Islamic contextAlbaghli, Basharhttps://hdl.handle.net/10023/156342019-09-24T02:02:31Z2017-01-01T00:00:00ZThis thesis examines the relationship between religiosity and prejudice in both a Western and Islamic context. The first part of the thesis examines the relationship between Christian religiosity and anti-Islamic attitudes (attitudes towards Islam and Muslims). The Muslim groups included Muslims from the Arabian Gulf, Asia, Middle-East, and native-born Muslims living in the West. Religious measurements focused on Christians were explored with measures of Fundamentalism, Intrinsic/Extrinsic religious orientations and the Post-Critical Belief scale. Two Studies were conducted in the UK (Study 1; N=339 and Study 2; N=299) and the results revealed that fundamentalism predicted negative attitudes toward Islam and Muslims. Further, the Factor Analyses (FA) and Structural models (SEM) supported a single underlying dimension for anti-Islamic attitudes (outcome variables).
Next, two additional studies were carried out in the US, with Study 3 (N=228) conducted immediately prior to the 2016 US presidential elections including similar measures of Islamophobia and multiple measures of religiosity. The same sample was followed up several months after the elections (Study 4; N=111). The results in the American context were in line with the previous studies in the UK. Following these studies in a Western context, the final study was conducted (in Arabic) in an Islamic context (Study 5; N=270). Most of the sample participants were from Kuwait, Saudi Arabia, Iraq, Egypt, and followed by other Arab countries. The sample also included Sunni, Shia, and ex-Muslims.
Since there has been less research on these issues in the Islamic context, new measures were developed to look at general Muslim religiosity, Islamic Fundamentalism, attitudes toward Christians, Jewish, and toward the West. The new scales were analysed using factor analysis, and the overall data examined with SEM to explore models analogous to those explored in the UK and US contexts. The findings in this study reveal that Muslim religiosity and Islamic fundamentalism are significant predictors of prejudiced attitudes toward Christians, Jewish, and the West. The conclusion highlights the importance of these findings, specifically to clarify the role of religion on these particular prejudices that are so central to current world conflicts. Limitations and avenues for future research are also discussed.
2017-01-01T00:00:00ZAlbaghli, BasharThis thesis examines the relationship between religiosity and prejudice in both a Western and Islamic context. The first part of the thesis examines the relationship between Christian religiosity and anti-Islamic attitudes (attitudes towards Islam and Muslims). The Muslim groups included Muslims from the Arabian Gulf, Asia, Middle-East, and native-born Muslims living in the West. Religious measurements focused on Christians were explored with measures of Fundamentalism, Intrinsic/Extrinsic religious orientations and the Post-Critical Belief scale. Two Studies were conducted in the UK (Study 1; N=339 and Study 2; N=299) and the results revealed that fundamentalism predicted negative attitudes toward Islam and Muslims. Further, the Factor Analyses (FA) and Structural models (SEM) supported a single underlying dimension for anti-Islamic attitudes (outcome variables).
Next, two additional studies were carried out in the US, with Study 3 (N=228) conducted immediately prior to the 2016 US presidential elections including similar measures of Islamophobia and multiple measures of religiosity. The same sample was followed up several months after the elections (Study 4; N=111). The results in the American context were in line with the previous studies in the UK. Following these studies in a Western context, the final study was conducted (in Arabic) in an Islamic context (Study 5; N=270). Most of the sample participants were from Kuwait, Saudi Arabia, Iraq, Egypt, and followed by other Arab countries. The sample also included Sunni, Shia, and ex-Muslims.
Since there has been less research on these issues in the Islamic context, new measures were developed to look at general Muslim religiosity, Islamic Fundamentalism, attitudes toward Christians, Jewish, and toward the West. The new scales were analysed using factor analysis, and the overall data examined with SEM to explore models analogous to those explored in the UK and US contexts. The findings in this study reveal that Muslim religiosity and Islamic fundamentalism are significant predictors of prejudiced attitudes toward Christians, Jewish, and the West. The conclusion highlights the importance of these findings, specifically to clarify the role of religion on these particular prejudices that are so central to current world conflicts. Limitations and avenues for future research are also discussed.Behavioral conservatism is linked to complexity of behavior in chimpanzees (Pan troglodytes) : implications for cognition and cumulative cultureDavis, Sarah J.Schapiro, Steven J.Lambeth, Susan P.Wood, Lara A.Whiten, Andrewhttps://hdl.handle.net/10023/156102024-02-22T00:42:30Z2018-07-19T00:00:00ZCumulative culture is rare, if not altogether absent in non-human species. At the foundation of cumulative learning is the ability to modify, relinquish or build upon prior behaviors flexibly to make them more productive or efficient. Within the primate literature, a failure to optimize solutions in this way is often proposed to derive from low-fidelity copying of witnessed behaviors, sub-optimal social learning heuristics, or a lack of relevant socio-cognitive adaptations. However, humans can also be markedly inflexible in their behaviors, perseverating with, or becoming fixated on outdated or inappropriate responses. Humans show differential patterns of flexibility as a function of cognitive load, exhibiting difficulties with inhibiting sub-optimal behaviors when there are high demands on working memory. We present a series of studies on captive chimpanzees which indicate that behavioral conservatism in apes may be underlain by similar constraints: chimpanzees showed relatively little conservatism when behavioral optimization involved the inhibition of a well-established but simple solution, or the addition of a simple modification to a well-established but complex solution. In contrast, when behavioral optimization involved the inhibition of a well-established but complex solution, chimpanzees showed evidence of conservatism. We propose that conservatism is linked to behavioral complexity, potentially mediated by cognitive resource availability, and may be an important factor in the evolution of cumulative culture.
2018-07-19T00:00:00ZDavis, Sarah J.Schapiro, Steven J.Lambeth, Susan P.Wood, Lara A.Whiten, AndrewCumulative culture is rare, if not altogether absent in non-human species. At the foundation of cumulative learning is the ability to modify, relinquish or build upon prior behaviors flexibly to make them more productive or efficient. Within the primate literature, a failure to optimize solutions in this way is often proposed to derive from low-fidelity copying of witnessed behaviors, sub-optimal social learning heuristics, or a lack of relevant socio-cognitive adaptations. However, humans can also be markedly inflexible in their behaviors, perseverating with, or becoming fixated on outdated or inappropriate responses. Humans show differential patterns of flexibility as a function of cognitive load, exhibiting difficulties with inhibiting sub-optimal behaviors when there are high demands on working memory. We present a series of studies on captive chimpanzees which indicate that behavioral conservatism in apes may be underlain by similar constraints: chimpanzees showed relatively little conservatism when behavioral optimization involved the inhibition of a well-established but simple solution, or the addition of a simple modification to a well-established but complex solution. In contrast, when behavioral optimization involved the inhibition of a well-established but complex solution, chimpanzees showed evidence of conservatism. We propose that conservatism is linked to behavioral complexity, potentially mediated by cognitive resource availability, and may be an important factor in the evolution of cumulative culture.Title redactedKuruvilla, Maneeshhttps://hdl.handle.net/10023/155972023-07-20T08:54:58Z2018-01-01T00:00:00Z2018-01-01T00:00:00ZKuruvilla, ManeeshSocial and personal psychological influences on individual engagement with global climate changeOgunbode, Charles Adedayohttps://hdl.handle.net/10023/155192019-04-01T10:41:52Z2018-01-01T00:00:00ZThe aim of this thesis was to examine the way individual responses to global climate change are determined by intrapersonal, social and experiential factors through three streams of research. The first stream employs cross-sectional and experimental methods to demonstrate that the influence of climate change information on behavioural intentions among two African populations is largely conveyed indirectly through perceived threat and concern. My findings support a view that a failure to account for the indirect effects of knowledge may have resulted in a systematic underestimation of its importance as a basis for environmental action.
In the second stream, I sought to resolve previous inconsistencies in the evidence for a link between flooding experiences and climate change engagement. Using secondary data analysis, I found that political affiliation modulates the link between flooding experience and preparedness to engage in climate change mitigation behaviour in the UK, such that the indirect links between flooding experience and preparedness to reduce energy use, and willingness to pay higher prices for energy efficient products, was stronger among left-leaning voters. These results were followed up with four experimental studies in which flooding experience was operationalised with a mental simulation technique. The experiments were designed to examine how values and attribution may moderate the effects of flooding experiences on climate change attitudes, but they did not yield any conclusive findings.
Finally, I examined the interplay between descriptive and injunctive social norms as influences of behavioural engagement with climate change using cross-sectional and experimental data. I found that social norms may influence behavioural engagement with climate change indirectly through their effects on individuals’ perceptions of, and emotional responses to, the problem. However, the nature of this influence may also be dependent on the convergence of the two norm types and the level of individuals’ intrinsic prioritization of pro-environmental outcomes.
2018-01-01T00:00:00ZOgunbode, Charles AdedayoThe aim of this thesis was to examine the way individual responses to global climate change are determined by intrapersonal, social and experiential factors through three streams of research. The first stream employs cross-sectional and experimental methods to demonstrate that the influence of climate change information on behavioural intentions among two African populations is largely conveyed indirectly through perceived threat and concern. My findings support a view that a failure to account for the indirect effects of knowledge may have resulted in a systematic underestimation of its importance as a basis for environmental action.
In the second stream, I sought to resolve previous inconsistencies in the evidence for a link between flooding experiences and climate change engagement. Using secondary data analysis, I found that political affiliation modulates the link between flooding experience and preparedness to engage in climate change mitigation behaviour in the UK, such that the indirect links between flooding experience and preparedness to reduce energy use, and willingness to pay higher prices for energy efficient products, was stronger among left-leaning voters. These results were followed up with four experimental studies in which flooding experience was operationalised with a mental simulation technique. The experiments were designed to examine how values and attribution may moderate the effects of flooding experiences on climate change attitudes, but they did not yield any conclusive findings.
Finally, I examined the interplay between descriptive and injunctive social norms as influences of behavioural engagement with climate change using cross-sectional and experimental data. I found that social norms may influence behavioural engagement with climate change indirectly through their effects on individuals’ perceptions of, and emotional responses to, the problem. However, the nature of this influence may also be dependent on the convergence of the two norm types and the level of individuals’ intrinsic prioritization of pro-environmental outcomes.The forgotten childrenPollock, Linda Annehttps://hdl.handle.net/10023/154112019-04-01T10:41:57Z1981-01-01T00:00:00ZThe prevailing viewpoint on the history of childhood is that: (a) there was no concept of childhood prior to the 17th century; (b) children were cruelly disciplined; (c) there was a formal parent-child relationship. The evidence presented to support the thesis is suspect and there is little systematic analysis of any source. Moreover, the thesis is not universally accepted - other authors have shown that there was a concept of childhood in the middle ages. In addition, the main writers have concentrated on discipline, to the virtual exclusion of all other childhood experiences. This study, covering the period from the 16th to the 19th century inclusive, has attempted to provide a detailed analysis of primary sources of evidence (autobiographies and diaries) in order to reconstruct child life in the past. Newspaper reports on child abuse cases occurring before the prevention of cruelty to children act in 1009 have also been examined. The methodological problems inherent in the sources used have been considered. The information provided by the texts suggests that parents did possess a concept of childhood, were not indifferent to their children and did not treat the latter cruelly. (With reference to the last point, the newspaper reports also reveal that child abuse was condemned before specific child protection legislation appeared). Although there was discord between parents and adolescent offspring, in the vast majority of families there was an affectionate parent-child relationship. Parents did not totally control their children's lives. Moreover, the texts suggest that the basics of child life have changed very little. Children did pass through such developmental stages as teething and talking at a similar age to modern children, although the texts do disclose the considerable amount of individual variation. Children played and also received at least some education in every century studied. Nonetheless there have been some changes in parental care and child life, as revealed in the texts: the concept of the innocence of childhood did not appear till the 10th century; there was an increase in thinking about the nature of childhood and the parental role in the abstract; there was a lessening of parental control in such areas as career and marriage through the centuries and there was an increase in the severity of the discipline meted out to children in the early 19th century.
1981-01-01T00:00:00ZPollock, Linda AnneThe prevailing viewpoint on the history of childhood is that: (a) there was no concept of childhood prior to the 17th century; (b) children were cruelly disciplined; (c) there was a formal parent-child relationship. The evidence presented to support the thesis is suspect and there is little systematic analysis of any source. Moreover, the thesis is not universally accepted - other authors have shown that there was a concept of childhood in the middle ages. In addition, the main writers have concentrated on discipline, to the virtual exclusion of all other childhood experiences. This study, covering the period from the 16th to the 19th century inclusive, has attempted to provide a detailed analysis of primary sources of evidence (autobiographies and diaries) in order to reconstruct child life in the past. Newspaper reports on child abuse cases occurring before the prevention of cruelty to children act in 1009 have also been examined. The methodological problems inherent in the sources used have been considered. The information provided by the texts suggests that parents did possess a concept of childhood, were not indifferent to their children and did not treat the latter cruelly. (With reference to the last point, the newspaper reports also reveal that child abuse was condemned before specific child protection legislation appeared). Although there was discord between parents and adolescent offspring, in the vast majority of families there was an affectionate parent-child relationship. Parents did not totally control their children's lives. Moreover, the texts suggest that the basics of child life have changed very little. Children did pass through such developmental stages as teething and talking at a similar age to modern children, although the texts do disclose the considerable amount of individual variation. Children played and also received at least some education in every century studied. Nonetheless there have been some changes in parental care and child life, as revealed in the texts: the concept of the innocence of childhood did not appear till the 10th century; there was an increase in thinking about the nature of childhood and the parental role in the abstract; there was a lessening of parental control in such areas as career and marriage through the centuries and there was an increase in the severity of the discipline meted out to children in the early 19th century.The development of spatial knowledge and orientationConning, Alison M.https://hdl.handle.net/10023/151452019-04-01T10:40:25Z1985-01-01T00:00:00ZThis thesis describes a series of experiments which investigate preschool children's spatial abilities. To overcome the problems of extrapolating from traditional laboratory task to abilities in the real world, the children were tested in 'natural' environments, such as buildings and streets, and which were large-scale, that is, they could not be viewed in their entirety from one position but instead had to be constructed from successive views. The measure of spatial knowledge chosen was direction estimation, a task which has been successfully used by other authors with older subjects, and which avoids the problems of interpretation and comprehension inherent in more traditional methods of investigating spatial representation such as map drawing and model building. The findings are discussed in relation to Piaget's distinction between topological and Euclidean spatial knowledge (Piaget et al. 1960; Piaget and Inhelder 1967; Piaget 1977), but traditionally used interpretations of his theory are avoided (e.g. Siegel and White 1975) as being based upon methodologically problematical experimentation. The results are interpreted in terms of Byrne's (1979, 1982) network-map/vector-map theory of spatial knowledge, which has only previously been applied to adults. It was found that preschool children can show both network-map knowledge (topological), and vector-map knowledge (Euclidean). Piaget's stage theory of development is inappropriate as within the age and ability range tested here, the type of spatial knowledge shown was more dependent upon qualities of the environment than of the child. Preschool children are most likely to show vector-map knowledge in small, over-learned, and actively explored environments than in larger passively explored but familiar environments, and lastly in novel large environments. Preschool children's network-map knowledge, built up by walking in natural environments, is coded in one direction only; and two separately learned but overlapping routes are encoded as an integrated network.
1985-01-01T00:00:00ZConning, Alison M.This thesis describes a series of experiments which investigate preschool children's spatial abilities. To overcome the problems of extrapolating from traditional laboratory task to abilities in the real world, the children were tested in 'natural' environments, such as buildings and streets, and which were large-scale, that is, they could not be viewed in their entirety from one position but instead had to be constructed from successive views. The measure of spatial knowledge chosen was direction estimation, a task which has been successfully used by other authors with older subjects, and which avoids the problems of interpretation and comprehension inherent in more traditional methods of investigating spatial representation such as map drawing and model building. The findings are discussed in relation to Piaget's distinction between topological and Euclidean spatial knowledge (Piaget et al. 1960; Piaget and Inhelder 1967; Piaget 1977), but traditionally used interpretations of his theory are avoided (e.g. Siegel and White 1975) as being based upon methodologically problematical experimentation. The results are interpreted in terms of Byrne's (1979, 1982) network-map/vector-map theory of spatial knowledge, which has only previously been applied to adults. It was found that preschool children can show both network-map knowledge (topological), and vector-map knowledge (Euclidean). Piaget's stage theory of development is inappropriate as within the age and ability range tested here, the type of spatial knowledge shown was more dependent upon qualities of the environment than of the child. Preschool children are most likely to show vector-map knowledge in small, over-learned, and actively explored environments than in larger passively explored but familiar environments, and lastly in novel large environments. Preschool children's network-map knowledge, built up by walking in natural environments, is coded in one direction only; and two separately learned but overlapping routes are encoded as an integrated network.Learning how to learn : the development of memory in 3-6 year-oldsWhittaker, Stephenhttps://hdl.handle.net/10023/151442019-04-01T10:40:41Z1984-01-01T00:00:00ZThe aim of the present study was to investigate the development of children's ability to make use of external sources of information when they are studying or remembering different types of information. More specifically, the research was directed at two recurring problems for theories of memory development: the production deficit; and the problem of change. The production deficit describes children's failure to spontaneously use a strategy which is 'in' their behavioural repertoire. Use of the strategy can be induced with minimal training. The study contains a set of experiments which suggest a number of reasons why children may fail to use available strategies. Another major problem with theories of memory development lies in explaining changes in strategy use. Three experiments address the issue, and suggest two mechanisms which produce such changes. The experiments indicate that feedback may provide one means by which routines already in the cognitive system are generalised to serve memory goals. Monitoring of one's own performance may also produce such changes. These mechanisms are incorporated into a model of how early strategies might develop. Other theories of memory development have stressed young children's lack of knowledge about their own memory processes. This has been invoked to explain both the production deficit and developmental change. Apart from the demonstrations that monitoring may influence strategy generalization, the study found little evidence that knowledge about memory is related to either of these phenomena. Current theories of the development of knowledge about memory are reviewed, and it is suggested that there are major problems with explanations of memory which appeal to such knowledge. One weakness of such theories is that they fail to explain the origins of this knowledge. The present study provides an account of the early development of knowledge about memory. The results of the experiments are also considered in the light of recent speculations about developmental theories and also memory processes in adults. It is suggested that the mechanisms of change demonstrated in this study may well apply to other areas of development. It is also argued that recent theories may have misrepresented the nature of adult memory processes.
1984-01-01T00:00:00ZWhittaker, StephenThe aim of the present study was to investigate the development of children's ability to make use of external sources of information when they are studying or remembering different types of information. More specifically, the research was directed at two recurring problems for theories of memory development: the production deficit; and the problem of change. The production deficit describes children's failure to spontaneously use a strategy which is 'in' their behavioural repertoire. Use of the strategy can be induced with minimal training. The study contains a set of experiments which suggest a number of reasons why children may fail to use available strategies. Another major problem with theories of memory development lies in explaining changes in strategy use. Three experiments address the issue, and suggest two mechanisms which produce such changes. The experiments indicate that feedback may provide one means by which routines already in the cognitive system are generalised to serve memory goals. Monitoring of one's own performance may also produce such changes. These mechanisms are incorporated into a model of how early strategies might develop. Other theories of memory development have stressed young children's lack of knowledge about their own memory processes. This has been invoked to explain both the production deficit and developmental change. Apart from the demonstrations that monitoring may influence strategy generalization, the study found little evidence that knowledge about memory is related to either of these phenomena. Current theories of the development of knowledge about memory are reviewed, and it is suggested that there are major problems with explanations of memory which appeal to such knowledge. One weakness of such theories is that they fail to explain the origins of this knowledge. The present study provides an account of the early development of knowledge about memory. The results of the experiments are also considered in the light of recent speculations about developmental theories and also memory processes in adults. It is suggested that the mechanisms of change demonstrated in this study may well apply to other areas of development. It is also argued that recent theories may have misrepresented the nature of adult memory processes.Children's judgements of sameness-difference among schematic facesRoy, Carolyn Maryhttps://hdl.handle.net/10023/151432019-04-01T10:41:18Z1983-01-01T00:00:00ZResearchers have found that young children often make "confusion errors" in judging visual stimuli for sameness. That is, children are reported to treat as "just the same" stimuli that are not identical in all respects. Explanations of these confusion errors have focussed on separate aspects of children's performance: language development (e.g., acquisition of relational terms), or perceptual and cognitive development (e.g., visual scanning or selection of criteria! features). The latter appear more successful in explaining the types of errors manifested. For instance, Taylor (1973) found that children, judging sameness among schematic faces, consistently correctly matched particular features and confused others, and later evidence (Wales, pers. comm., 1974) suggested their responses may be affected by the presence or absence of a visual frame around the face .The present series of experiments investigated potential influences on judgments of sameness among sets of schematic faces by children of pre-school and early school age. Variables examined included presence of a visual frame of reference around the face, type of stimulus array, task requirements, and salience of stimulus features relative to each other. Initial results confirmed that, in tasks like matching-from-sample or pair-comparison, children systematically matched only certain features of the faces and confused other features. Type of task (including stimulus and response variables) and presence/absence of a visual frame interacted with each other to influence the response patterns. Subsequent experiments suggested that neither objective visual salience of one stimulus feature over another, nor selection of a visual criterial attribute, satisfactorily accounted for the observed response patterns. A more likely contributor was subjective weighting of features on grounds of their contextually-afforded significance. Faces were not compared feature-by-feature; instead, the criterion seemed to be sameness of affective expression conveyed. It is argued that many of the confusion errors were not due simply to linguistic or perceptual immaturity. Rather, in circumstances where adults take "same" to refer to identity across all features, the children took it as "same kind of thing": their responses reflected their bases for classifying the faces (i.e., by affective content) rather than ability to judge identity. Having judged unidentical faces as the same, a considerable number of children indicated in justifying their judgments that while certain features were the same, others were not. Thus they appeared able to understand and use "same" in its various adult senses, but interpreted the task instructions differently from adults.
1983-01-01T00:00:00ZRoy, Carolyn MaryResearchers have found that young children often make "confusion errors" in judging visual stimuli for sameness. That is, children are reported to treat as "just the same" stimuli that are not identical in all respects. Explanations of these confusion errors have focussed on separate aspects of children's performance: language development (e.g., acquisition of relational terms), or perceptual and cognitive development (e.g., visual scanning or selection of criteria! features). The latter appear more successful in explaining the types of errors manifested. For instance, Taylor (1973) found that children, judging sameness among schematic faces, consistently correctly matched particular features and confused others, and later evidence (Wales, pers. comm., 1974) suggested their responses may be affected by the presence or absence of a visual frame around the face .The present series of experiments investigated potential influences on judgments of sameness among sets of schematic faces by children of pre-school and early school age. Variables examined included presence of a visual frame of reference around the face, type of stimulus array, task requirements, and salience of stimulus features relative to each other. Initial results confirmed that, in tasks like matching-from-sample or pair-comparison, children systematically matched only certain features of the faces and confused other features. Type of task (including stimulus and response variables) and presence/absence of a visual frame interacted with each other to influence the response patterns. Subsequent experiments suggested that neither objective visual salience of one stimulus feature over another, nor selection of a visual criterial attribute, satisfactorily accounted for the observed response patterns. A more likely contributor was subjective weighting of features on grounds of their contextually-afforded significance. Faces were not compared feature-by-feature; instead, the criterion seemed to be sameness of affective expression conveyed. It is argued that many of the confusion errors were not due simply to linguistic or perceptual immaturity. Rather, in circumstances where adults take "same" to refer to identity across all features, the children took it as "same kind of thing": their responses reflected their bases for classifying the faces (i.e., by affective content) rather than ability to judge identity. Having judged unidentical faces as the same, a considerable number of children indicated in justifying their judgments that while certain features were the same, others were not. Thus they appeared able to understand and use "same" in its various adult senses, but interpreted the task instructions differently from adults.Parental support of cognitive development in infancyMoseley, Jeanhttps://hdl.handle.net/10023/151402019-04-01T10:40:54Z1981-01-01T00:00:00ZThis study examines the nature of parental involvement in the infants' play with objects (toys) and the effectiveness of the various forms of the parent's (mother's) intervention on the infant's cognitive growth. Assessment of the levels of the infants' cognitive competence were obtained through the administration of the Uzgiria and Hunt's "Infants Psychological Development Scales" which provided a formal measure of performance in various tasks that are related to specific areas of sensorimotor intelligence. Videotapes of 15-minute mother-infant play sessions in their homes, involving 6-, 9-, 12- and 15-month-old infants were quantified in terms of maternal and infant categories of behaviour that described variations in the involvement and complexity of the mothers' participation and the cognitive and social components of the infants' orientation to toys in an interpersonal context. Besides this cross-sectional method of data- collection, for each group, a quasi-longitudinal approach was adopted to trace the developmental changes of interpersonal play with objects across a period of three months. Analyses of maternal categories revealed quantitative and qualitative changes in maternal style of interaction as a function of the infant's age, as well as his level of cognitive abilities -relative to age peers. Mothers of 6-manth-olds were different from the mothers in the other groups in that they directed their infants' play into specific channels to an equal extent as their passive participation in the infants' spontaneous manipulative acts. All the other mothers adopted this latter 'enhancing' role to a greater extent than the former 'modifying' one. All mothers engaged in very little structured 'teaching' and very little 'assistance' of their infants. Analysis of the infants' data showed definite developmental changes in all forms of infants' orientation to objects in an interpersonal context. Cooperative play became noticeably more frequent and was more often infant-initiated after age 15 months. Rejection of play with the mother and lack of concentration on the play-task was characteristic of the 9-12 month-old infants. From the data, three conclusions were derived with respect to parental support and its effectiveness. Firstly, parents encourage autonomy and spontaneity in the infant since they 'enhance interaction' with the toys more than they 'modify' it. 'Modifying' is situation-specific in the sense that it increased when the infants' spontaneous manipulations were relatively infrequent, or when they were characterised by a low-level of cognitive complexity, or when the infant was less advanced than his peers on the sensorimotor intelligence scales. However, with age increases the mothers increased their demands from the infants by initiating more tasks for them to reciprocate. The second conclusion is that when the mothers 'modify' interaction they time their activities in accordance with the infants' ongoing behaviour thereby encouraging the infants' attention to the mother and increasing the likelihood of achieving the goal set by her. The third conclusion relates to the effectiveness of parental intervention. Infants whose age was above 9 months seemed to be more dependent on, and more affected by, their mothers' directive intervention. These findings are discussed in terms of the implication for child- rearing practices and pre-school education.
1981-01-01T00:00:00ZMoseley, JeanThis study examines the nature of parental involvement in the infants' play with objects (toys) and the effectiveness of the various forms of the parent's (mother's) intervention on the infant's cognitive growth. Assessment of the levels of the infants' cognitive competence were obtained through the administration of the Uzgiria and Hunt's "Infants Psychological Development Scales" which provided a formal measure of performance in various tasks that are related to specific areas of sensorimotor intelligence. Videotapes of 15-minute mother-infant play sessions in their homes, involving 6-, 9-, 12- and 15-month-old infants were quantified in terms of maternal and infant categories of behaviour that described variations in the involvement and complexity of the mothers' participation and the cognitive and social components of the infants' orientation to toys in an interpersonal context. Besides this cross-sectional method of data- collection, for each group, a quasi-longitudinal approach was adopted to trace the developmental changes of interpersonal play with objects across a period of three months. Analyses of maternal categories revealed quantitative and qualitative changes in maternal style of interaction as a function of the infant's age, as well as his level of cognitive abilities -relative to age peers. Mothers of 6-manth-olds were different from the mothers in the other groups in that they directed their infants' play into specific channels to an equal extent as their passive participation in the infants' spontaneous manipulative acts. All the other mothers adopted this latter 'enhancing' role to a greater extent than the former 'modifying' one. All mothers engaged in very little structured 'teaching' and very little 'assistance' of their infants. Analysis of the infants' data showed definite developmental changes in all forms of infants' orientation to objects in an interpersonal context. Cooperative play became noticeably more frequent and was more often infant-initiated after age 15 months. Rejection of play with the mother and lack of concentration on the play-task was characteristic of the 9-12 month-old infants. From the data, three conclusions were derived with respect to parental support and its effectiveness. Firstly, parents encourage autonomy and spontaneity in the infant since they 'enhance interaction' with the toys more than they 'modify' it. 'Modifying' is situation-specific in the sense that it increased when the infants' spontaneous manipulations were relatively infrequent, or when they were characterised by a low-level of cognitive complexity, or when the infant was less advanced than his peers on the sensorimotor intelligence scales. However, with age increases the mothers increased their demands from the infants by initiating more tasks for them to reciprocate. The second conclusion is that when the mothers 'modify' interaction they time their activities in accordance with the infants' ongoing behaviour thereby encouraging the infants' attention to the mother and increasing the likelihood of achieving the goal set by her. The third conclusion relates to the effectiveness of parental intervention. Infants whose age was above 9 months seemed to be more dependent on, and more affected by, their mothers' directive intervention. These findings are discussed in terms of the implication for child- rearing practices and pre-school education.Cognitive processing in complex situations : the dynamics of information flowLee, Robert Brucehttps://hdl.handle.net/10023/151392019-04-01T10:41:39Z1974-01-01T00:00:00ZThe thesis describes and develops a new theoretical approach to the study of human cognitive processing performance in complex situation so this approach utilises and integrates existing theoretical and empirical data from a number of traditionally separate areas of Information processing psychology, such as cognition, perception, memory, imagery, skill and vigilance. Contemporary cognitive psychology considers perception, memory and imagery as functionally inter-related and inter-dependent processes characterised by active, constructive, conscious information processing. In the present thesis the implications of this view are extended, in that this processing is considered to occupy the cognitive processing capacity of the subject in qualitatively the same way as does normal decision-making, problem-solving, or conscious Internalised thought processing of any kind. The theoretical approach of the thesis stresses and accepts the functional inter-relationship and inter-dependence of the various higher mental processes, and is primarily concerned with the sustained dynamic performance properties of the total system. The nature of the research emphasis and direction of the thesis originates from the author's direct concern with applied problems resulting from the increasing cognitive load imposed upon human operators in present complex man-machine systems, such as jet aircraft, for example. Performance failure of the human operator in these systems often has very serious consequences. There is a critical lack of knowledge regarding the fundamental nature and limitations of human information processing in such situations. The basic motivation behind the work reported in the thesis was that, in order to study meaningfully the relevant aspects of the applied situation, further pure research, both theoretical and empirical, had to be undertaken to clarify particular issues. A new conceptual approach to vigilance-type situations is suggested by the theory developed in the thesis, A task was devised in which the signals to be detected were clearly visible, but embedded at random in complex visual patterns (photographs). These patterns were presented on a television screen at regular intervals, over 600 times to subjects during a single testing session. At each of these presentations subjects had to respond with respect to the identification of the picture shown; and to the presence or absence of a signal within it. From the theory it was predicted that where the complex pattern remained the same throughout the testing session, signal detection performance would show a typical vigilance decrement. However, when the set of possible pictures in which the signal may or may not be embedded is vastly increased, and the subject' has to respond at each event in the manner described, it was predicted that signal detection performance would be significantly improved in relation to the single picture condition. These predictions were empirically confirmed at a highly significant level. (On the basis of visual signal-to-noise ratios only, a signal detection analysis of the experimental situation would predict a result opposite to that actually obtained in the experiment). A computer simulation program based on fundamental theoretical ideas outlined in the thesis was developed. The program was used to simulate the vigilance experiment reported in the dissertation. The purpose and implications of the use of this technique as an applied research tool are discussed. The final chapter discusses the results achieved, and outlines the proposed application of the theoretical ideas, and empirical results of the research to the cognitive load problems of human operators in real man-machine systems, in particular aircrew flying advanced jet aircraft.
1974-01-01T00:00:00ZLee, Robert BruceThe thesis describes and develops a new theoretical approach to the study of human cognitive processing performance in complex situation so this approach utilises and integrates existing theoretical and empirical data from a number of traditionally separate areas of Information processing psychology, such as cognition, perception, memory, imagery, skill and vigilance. Contemporary cognitive psychology considers perception, memory and imagery as functionally inter-related and inter-dependent processes characterised by active, constructive, conscious information processing. In the present thesis the implications of this view are extended, in that this processing is considered to occupy the cognitive processing capacity of the subject in qualitatively the same way as does normal decision-making, problem-solving, or conscious Internalised thought processing of any kind. The theoretical approach of the thesis stresses and accepts the functional inter-relationship and inter-dependence of the various higher mental processes, and is primarily concerned with the sustained dynamic performance properties of the total system. The nature of the research emphasis and direction of the thesis originates from the author's direct concern with applied problems resulting from the increasing cognitive load imposed upon human operators in present complex man-machine systems, such as jet aircraft, for example. Performance failure of the human operator in these systems often has very serious consequences. There is a critical lack of knowledge regarding the fundamental nature and limitations of human information processing in such situations. The basic motivation behind the work reported in the thesis was that, in order to study meaningfully the relevant aspects of the applied situation, further pure research, both theoretical and empirical, had to be undertaken to clarify particular issues. A new conceptual approach to vigilance-type situations is suggested by the theory developed in the thesis, A task was devised in which the signals to be detected were clearly visible, but embedded at random in complex visual patterns (photographs). These patterns were presented on a television screen at regular intervals, over 600 times to subjects during a single testing session. At each of these presentations subjects had to respond with respect to the identification of the picture shown; and to the presence or absence of a signal within it. From the theory it was predicted that where the complex pattern remained the same throughout the testing session, signal detection performance would show a typical vigilance decrement. However, when the set of possible pictures in which the signal may or may not be embedded is vastly increased, and the subject' has to respond at each event in the manner described, it was predicted that signal detection performance would be significantly improved in relation to the single picture condition. These predictions were empirically confirmed at a highly significant level. (On the basis of visual signal-to-noise ratios only, a signal detection analysis of the experimental situation would predict a result opposite to that actually obtained in the experiment). A computer simulation program based on fundamental theoretical ideas outlined in the thesis was developed. The program was used to simulate the vigilance experiment reported in the dissertation. The purpose and implications of the use of this technique as an applied research tool are discussed. The final chapter discusses the results achieved, and outlines the proposed application of the theoretical ideas, and empirical results of the research to the cognitive load problems of human operators in real man-machine systems, in particular aircrew flying advanced jet aircraft.An investigation into the aesthetic and psychological effects of the soiling and cleaning of building facadesAndrew, Christopher A.https://hdl.handle.net/10023/151352019-04-01T10:42:20Z1994-01-01T00:00:00ZAs buildings age biological and non biological soiling accumulates on their facades. Soiling changes the visual appearance of buildings. This thesis investigates the aesthetic and perceptual changes which take place as a result of the accumulation of soiling. A series of experiments and surveys were conducted to investigate the effects soiling had on aesthetic and perceptual judgements of buildings. A multiple sorting procedure using photographs of buildings, revealed that both an aesthetic evaluation and soiling levels were important ways in which the buildings were conceptualised. A second study comparing photographs of architecturally similar buildings before and after stonecleaning had taken place, revealed large shifts in the evaluation of buildings following cleaning as measured by semantic differentials. Changes in evaluation were found to be dependent on the nature and outcome of the cleaning process. Buildings were also consistently perceived to be younger following cleaning. Surveys amongst residents of cities which had undergone major stonecleaning programmes revealed an awareness of this activity in line with theories of urban perception. Attitudes towards stonecleaning programmes was found to be generally favourable. A survey conducted amongst architects showed the complex range of aesthetic and perceptual effects which soiling and cleaning has on buildings. The surveys conducted amongst both the general public and architects revealed that while cleaned buildings were generally seen to be aesthetically more pleasing than heavily soiled ones, there were some situations where soiling could enhance the aesthetic appearance of buildings. A further study involving ratings of buildings which varied in terms of soiling was therefore conducted which further clarified the role of soiling in aesthetic judgements. Drawing on research in experimental and environmental aesthetics, as well as data from the reported experiments and surveys a model is proposed which relates soiling level to facade complexity and aesthetic evaluation.
1994-01-01T00:00:00ZAndrew, Christopher A.As buildings age biological and non biological soiling accumulates on their facades. Soiling changes the visual appearance of buildings. This thesis investigates the aesthetic and perceptual changes which take place as a result of the accumulation of soiling. A series of experiments and surveys were conducted to investigate the effects soiling had on aesthetic and perceptual judgements of buildings. A multiple sorting procedure using photographs of buildings, revealed that both an aesthetic evaluation and soiling levels were important ways in which the buildings were conceptualised. A second study comparing photographs of architecturally similar buildings before and after stonecleaning had taken place, revealed large shifts in the evaluation of buildings following cleaning as measured by semantic differentials. Changes in evaluation were found to be dependent on the nature and outcome of the cleaning process. Buildings were also consistently perceived to be younger following cleaning. Surveys amongst residents of cities which had undergone major stonecleaning programmes revealed an awareness of this activity in line with theories of urban perception. Attitudes towards stonecleaning programmes was found to be generally favourable. A survey conducted amongst architects showed the complex range of aesthetic and perceptual effects which soiling and cleaning has on buildings. The surveys conducted amongst both the general public and architects revealed that while cleaned buildings were generally seen to be aesthetically more pleasing than heavily soiled ones, there were some situations where soiling could enhance the aesthetic appearance of buildings. A further study involving ratings of buildings which varied in terms of soiling was therefore conducted which further clarified the role of soiling in aesthetic judgements. Drawing on research in experimental and environmental aesthetics, as well as data from the reported experiments and surveys a model is proposed which relates soiling level to facade complexity and aesthetic evaluation.Emergent untaught behaviour : stimulus equivalence and transitive inference in learning disabled and normally able peopleTeer, Kerryhttps://hdl.handle.net/10023/151342019-04-01T10:41:14Z1997-01-01T00:00:00ZThe explanation of the emergence of untaught behaviour has been a topic of considerable interest in behaviour analysis. The experiments in this thesis were designed to examine some of the processes underlying these emergent relations. In doing this, two different paradigms were examined - stimulus equivalence and transitive inference. The experiments leading to a formal definition of equivalence relations are reported, and the demonstration of cognitive abilities with both humans and non-humans described. The explanations proposed for the basis of stimulus equivalence are discussed. Data from five experiments are then presented. Experiment 1 considered the role of naming in stimulus equivalence and Experiment 2 contrasted this performance with the establishment of transitive inference, both experiments being carried out with adults with learning disabilities as subjects. The results from these experiments suggested that while naming behaviour may help to establish emergent relations, it may not be the basis of stimulus equivalence, and that it may be possible to account for performance on both stimulus equivalence and transitive inference tests in terms of reinforcement contingencies. While subjects who display stimulus equivalence are likely to also display transitive inferences, the reverse relation may not be true. Experiments 3 and 4 examined the effects of a disruption of the baseline relations on performance on transitive inference and stimulus equivalence tasks. These experiments were both carried out with normally able adults, adults with learning disabilities, and normally developing young children. Experiment 5 was a replication of Experiment 4 with a tighter methodology and a larger number of subjects with learning disabilities. It is suggested that the results obtained in Experiments 4 and 5 can be explained by the development of contextual control of the equivalence relations. The results from these experiments suggested that the transitive inference and stimulus equivalence paradigms may respectively be concrete and abstract examples of more general emergent relations. These paradigms may also prove to be very useful teaching tools for helping to establish emergent relations.
1997-01-01T00:00:00ZTeer, KerryThe explanation of the emergence of untaught behaviour has been a topic of considerable interest in behaviour analysis. The experiments in this thesis were designed to examine some of the processes underlying these emergent relations. In doing this, two different paradigms were examined - stimulus equivalence and transitive inference. The experiments leading to a formal definition of equivalence relations are reported, and the demonstration of cognitive abilities with both humans and non-humans described. The explanations proposed for the basis of stimulus equivalence are discussed. Data from five experiments are then presented. Experiment 1 considered the role of naming in stimulus equivalence and Experiment 2 contrasted this performance with the establishment of transitive inference, both experiments being carried out with adults with learning disabilities as subjects. The results from these experiments suggested that while naming behaviour may help to establish emergent relations, it may not be the basis of stimulus equivalence, and that it may be possible to account for performance on both stimulus equivalence and transitive inference tests in terms of reinforcement contingencies. While subjects who display stimulus equivalence are likely to also display transitive inferences, the reverse relation may not be true. Experiments 3 and 4 examined the effects of a disruption of the baseline relations on performance on transitive inference and stimulus equivalence tasks. These experiments were both carried out with normally able adults, adults with learning disabilities, and normally developing young children. Experiment 5 was a replication of Experiment 4 with a tighter methodology and a larger number of subjects with learning disabilities. It is suggested that the results obtained in Experiments 4 and 5 can be explained by the development of contextual control of the equivalence relations. The results from these experiments suggested that the transitive inference and stimulus equivalence paradigms may respectively be concrete and abstract examples of more general emergent relations. These paradigms may also prove to be very useful teaching tools for helping to establish emergent relations.The effect of social stereotypes on eyewitness behaviourFrowley, Jason N.https://hdl.handle.net/10023/151212019-04-01T10:40:56Z1994-01-01T00:00:00ZEyewitness behaviour is a very important issue in social psychology. Recent years have seen a boom in research in this area; however, very little of this research has addressed the important and fundamental issues raised by the social factors that are involved when eyewitnessing takes place. The present thesis reports research which addresses the effect of social- stereotypic information upon a number of aspects of the eyewitness situation. Of particular interest is the effect of stereotypic information upon the judgment of aggressive and violent actions, and face and body stimuli; on memory for information associated with a dramatic staged incident, when presented either before or after target material; and its impact in an eyewitness interview situation. Finally, an interview technique is designed and tested which aims to reduce the negative impact of stereotypic information on eyewitness memory. Throughout, the impact of stereotypic information presented at encoding and at retrieval is contrasted and compared. The effect of delay between encoding and retrieval is also considered. It is concluded that stereotypic information may affect judgments of information relevant to the eyewitnessing situation whether presented before or after target material. Similarly, stereotypic information may affect memory when it is presented before target material. Little effect is however to be expected on memory when stereotypic information is presented at retrieval, although the exact effects may be found to vary with the nature of the target stimuli used. The source-monitoring interview, based on research by Marcia Johnson and her colleagues, appears a promising means of reducing the distorting effect of stereotypes on memory; particularly when a delay occurs between the encoding and retrieval of target material.
1994-01-01T00:00:00ZFrowley, Jason N.Eyewitness behaviour is a very important issue in social psychology. Recent years have seen a boom in research in this area; however, very little of this research has addressed the important and fundamental issues raised by the social factors that are involved when eyewitnessing takes place. The present thesis reports research which addresses the effect of social- stereotypic information upon a number of aspects of the eyewitness situation. Of particular interest is the effect of stereotypic information upon the judgment of aggressive and violent actions, and face and body stimuli; on memory for information associated with a dramatic staged incident, when presented either before or after target material; and its impact in an eyewitness interview situation. Finally, an interview technique is designed and tested which aims to reduce the negative impact of stereotypic information on eyewitness memory. Throughout, the impact of stereotypic information presented at encoding and at retrieval is contrasted and compared. The effect of delay between encoding and retrieval is also considered. It is concluded that stereotypic information may affect judgments of information relevant to the eyewitnessing situation whether presented before or after target material. Similarly, stereotypic information may affect memory when it is presented before target material. Little effect is however to be expected on memory when stereotypic information is presented at retrieval, although the exact effects may be found to vary with the nature of the target stimuli used. The source-monitoring interview, based on research by Marcia Johnson and her colleagues, appears a promising means of reducing the distorting effect of stereotypes on memory; particularly when a delay occurs between the encoding and retrieval of target material.Human auditory information processingHicks, Ronald G.https://hdl.handle.net/10023/151182019-04-01T10:41:19Z1973-01-01T00:00:00ZThe purpose of this study is to investigate the flow of nonsymbolic auditory information in humans. To achieve this goal the observer adjusts the loudness of a Gaussian noise (GN) signal to match the perceived intensity of an electrodermal stimulus (EDS), a cross-modality matching task. The loudness of the GN and the voltage of the EDS mere maintained within the observer's (O's) sensory probabilistic zone. The sensory probabilistic zone is a range of stimulus intensity from somewhere above "no detection" to "100% detection". The independent variable is a binary condition in that it consisted of catch trials of the time and the remaining time of an EDS at a given intensity (previously determined at an intensity that elicited a response 50% of the time). Consequently, the O's adjustment of the GN reflected his decision-making processes, analysed by signal detection theory and cybernetics. Experiment one demonstrated that neither practice nor the experimenter influenced the O's performance. Also, there are no residual carry-over effects. The 0 has difficulty assigning relative value to the auditory signals and has little or no difficulty in combining, organizing or co-ordinating the auditory information. The second experiment demonstrated that the O's difficulty in assigning relative value to the signals is due to a short memory retention of the nonsymbolic auditory signals (half-life of less than a second). However, verbal confidence ratings (VCRs) add persistency to the auditory memory (echoic memory), its half-life is extended to about 3.1 seconds. The VCR has a half-life of about four seconds. Experiment three demonstrated that nonsymbolic auditory information processing is not affected by interfering signals. From a cybernetic model of the results it is concluded that nonsymbolic auditory information is processed by a filtered, single channel, series processor. Persistency is added to the system's memory component by an interaction between the auditory (echoic) memory and the conceptual symbolic system (VCR).
1973-01-01T00:00:00ZHicks, Ronald G.The purpose of this study is to investigate the flow of nonsymbolic auditory information in humans. To achieve this goal the observer adjusts the loudness of a Gaussian noise (GN) signal to match the perceived intensity of an electrodermal stimulus (EDS), a cross-modality matching task. The loudness of the GN and the voltage of the EDS mere maintained within the observer's (O's) sensory probabilistic zone. The sensory probabilistic zone is a range of stimulus intensity from somewhere above "no detection" to "100% detection". The independent variable is a binary condition in that it consisted of catch trials of the time and the remaining time of an EDS at a given intensity (previously determined at an intensity that elicited a response 50% of the time). Consequently, the O's adjustment of the GN reflected his decision-making processes, analysed by signal detection theory and cybernetics. Experiment one demonstrated that neither practice nor the experimenter influenced the O's performance. Also, there are no residual carry-over effects. The 0 has difficulty assigning relative value to the auditory signals and has little or no difficulty in combining, organizing or co-ordinating the auditory information. The second experiment demonstrated that the O's difficulty in assigning relative value to the signals is due to a short memory retention of the nonsymbolic auditory signals (half-life of less than a second). However, verbal confidence ratings (VCRs) add persistency to the auditory memory (echoic memory), its half-life is extended to about 3.1 seconds. The VCR has a half-life of about four seconds. Experiment three demonstrated that nonsymbolic auditory information processing is not affected by interfering signals. From a cybernetic model of the results it is concluded that nonsymbolic auditory information is processed by a filtered, single channel, series processor. Persistency is added to the system's memory component by an interaction between the auditory (echoic) memory and the conceptual symbolic system (VCR).Some philosophical theories of the visual perception of space and their relationships with experimental psychologyGray, John M.https://hdl.handle.net/10023/151162019-04-01T10:41:15Z1981-01-01T00:00:00ZChapter One introduces the theory which is based on three postulates derived from pragmatism, empiricism and constructivism respectively. Veridical perception is seen not as reflecting the world as it is in some absolute sense, but as providing guidance for effective action. Its ability to do this depends on its relationship to active touch. This relies on their both being forms of action, i.e. they both consist of the operation of schemata which are at the same time guides for action and products of action. The second chapter relates how versions of these postulates have appeared, singly or in pairs, in previous theories especially those of Berkeley, Kant and Schelling. Then MacMurray's theory, which embodies all three postulates is introduced, and this is related to Gibson's theory. Chapter Three discusses how the key terms in the theory, image, percept and schema, relate to each other, and argues that they all reflect the same underlying psychological process. Chapter Four is concerned with dynamic and hedonic aspects, with how perception relates to motivation and feeling. Conventional theories see any such relation as external and associative while those based on perceptual schemata allow both external and internal relationships. These different sorts of theory are compared over a wide range of phenomena. Only the schemata based theory can account for all of the effects. Chapter Five starts with a brief discussion of the limitations of information processing type models in psychology, particularly with respect to dynamic aspects. With these in mind, it goes on to develop an outline model. Construction of the model draws attention to two important aspects of the theory; the non-existence of a pure metric representation and the lack of any strictly causal link between retinal stimulation and percept. Chapter Six examines the literature on adaptation to optical re-arrangement, a convenient method of studying the relationship between spatial vision and touch which is a key issue for the theory. While the crucial re-arrangement is impossible to produce, the weight of evidence supports the sort of theory proposed here. Chapter Seven compares this theory to others, particularly Neisser's, and suggests other areas of application in both visual perception and general psychology.
1981-01-01T00:00:00ZGray, John M.Chapter One introduces the theory which is based on three postulates derived from pragmatism, empiricism and constructivism respectively. Veridical perception is seen not as reflecting the world as it is in some absolute sense, but as providing guidance for effective action. Its ability to do this depends on its relationship to active touch. This relies on their both being forms of action, i.e. they both consist of the operation of schemata which are at the same time guides for action and products of action. The second chapter relates how versions of these postulates have appeared, singly or in pairs, in previous theories especially those of Berkeley, Kant and Schelling. Then MacMurray's theory, which embodies all three postulates is introduced, and this is related to Gibson's theory. Chapter Three discusses how the key terms in the theory, image, percept and schema, relate to each other, and argues that they all reflect the same underlying psychological process. Chapter Four is concerned with dynamic and hedonic aspects, with how perception relates to motivation and feeling. Conventional theories see any such relation as external and associative while those based on perceptual schemata allow both external and internal relationships. These different sorts of theory are compared over a wide range of phenomena. Only the schemata based theory can account for all of the effects. Chapter Five starts with a brief discussion of the limitations of information processing type models in psychology, particularly with respect to dynamic aspects. With these in mind, it goes on to develop an outline model. Construction of the model draws attention to two important aspects of the theory; the non-existence of a pure metric representation and the lack of any strictly causal link between retinal stimulation and percept. Chapter Six examines the literature on adaptation to optical re-arrangement, a convenient method of studying the relationship between spatial vision and touch which is a key issue for the theory. While the crucial re-arrangement is impossible to produce, the weight of evidence supports the sort of theory proposed here. Chapter Seven compares this theory to others, particularly Neisser's, and suggests other areas of application in both visual perception and general psychology.A philosophical systematisation of the psychological concepts of Jung in relation to Neoplatonic traditionMori, Masakihttps://hdl.handle.net/10023/151142019-04-01T10:40:07Z1989-01-01T00:00:00ZJung developed various psychological concepts (for example, the 'archetypes') in an attempt to explain the special modalities of relationship between the noumenal (unconscious) realities, or between the noumenal (unconscious) and phenomenal (conscious) realities. However, in so doing, he left any coherent structural relationships between these concepts ambiguous. In this dissertation, therefore, I will attempt to shape the innate structural relationships of these concepts into a more philosophically-oriented, psycho-cosmological scheme. I will first devote my attention to two cosmogonic principles, the 'pleroma' and 'Abraxas', which occur in Jung's VII Sermones ad Mortuos. Then, after examining the structural similarities between these cosmogonic principles of Jung and the concepts articulated in the philosophical systems of pagan and Christian Neoplatonic thinkers, I will propose the possibility of an organic link between the two cosmogonic principles and the other psychological concepts in the main body of Jung's works, together with their formation into a complete psycho-cosmological scheme akin to the philosophical systems of the Neoplatonists. Secondly, I will give an exposition and analysis of the overall concepts of Jung, based on his own writings, on the interpretations placed on them by Jungian scholars such as von Franz, and on my own interpretations of Jung's concepts. Finally, I will examine in greater detail the philosophical system developed by Proclus, and, after comparing his concepts with the parallel but fragmentary concepts of Jung (fragmentary since they lack any clear structural interrelationships), I will conclude that Proclus' highly systematic philosophical system provides an ideal model, or philosophical schematisation, for the psychological concepts of Jung.
1989-01-01T00:00:00ZMori, MasakiJung developed various psychological concepts (for example, the 'archetypes') in an attempt to explain the special modalities of relationship between the noumenal (unconscious) realities, or between the noumenal (unconscious) and phenomenal (conscious) realities. However, in so doing, he left any coherent structural relationships between these concepts ambiguous. In this dissertation, therefore, I will attempt to shape the innate structural relationships of these concepts into a more philosophically-oriented, psycho-cosmological scheme. I will first devote my attention to two cosmogonic principles, the 'pleroma' and 'Abraxas', which occur in Jung's VII Sermones ad Mortuos. Then, after examining the structural similarities between these cosmogonic principles of Jung and the concepts articulated in the philosophical systems of pagan and Christian Neoplatonic thinkers, I will propose the possibility of an organic link between the two cosmogonic principles and the other psychological concepts in the main body of Jung's works, together with their formation into a complete psycho-cosmological scheme akin to the philosophical systems of the Neoplatonists. Secondly, I will give an exposition and analysis of the overall concepts of Jung, based on his own writings, on the interpretations placed on them by Jungian scholars such as von Franz, and on my own interpretations of Jung's concepts. Finally, I will examine in greater detail the philosophical system developed by Proclus, and, after comparing his concepts with the parallel but fragmentary concepts of Jung (fragmentary since they lack any clear structural interrelationships), I will conclude that Proclus' highly systematic philosophical system provides an ideal model, or philosophical schematisation, for the psychological concepts of Jung.Bayesian analysis for quantification of individual rat and human behavioural patterns during attentional set-shifting tasksWang, Jiachaohttps://hdl.handle.net/10023/148432019-04-01T10:40:10Z2018-06-29T00:00:00ZAttentional set-shifting tasks, consisting of multiple stages of discrimination learning,
have been widely used in animals and humans to investigate behavioural flexibility.
However, there are several learning criteria (e.g., 6-correct-choice-in-a-row, or 10-out-
of-12-correct) by which a subject might be judged to have learned a discrimination.
Furthermore, the currently frequentist approach does not provide a detailed analysis of
individual performance. In this PhD study, a large set of archival data of rats
performing a 7-stage intra-dimensional/extra-dimensional (ID/ED) attentional set-
shifting task was analysed, using a novel Bayesian analytical approach, to estimate
each rat’s learning processes over its trials within the task. The analysis showed that
the Bayesian learning criterion may be an appropriate alternative to the frequentist n-
correct-in-a-row criterion for studying performance. The individual analysis of rats’
behaviour using the Bayesian model also suggested that the rats responded according
to a number of irrelevant spatial and perceptual information sources before the correct
stimulus-reward association was established. The efficacy of the Bayesian analysis of
individual subjects’ behaviour and the appropriateness of the Bayesian learning
criterion were also supported by the analysis of simulated data in which the
behavioural choices in the task were generated by known rules. Additionally, the
efficacy was also supported by analysis of human behaviour during an analogous
human 7-stage attentional set-shifting task, where participants’ detailed learning
processes were collected based on their trial-by-trial oral report. Further, an extended
Bayesian approach, which considers the effects of feedback (correct vs incorrect) after
each response in the task, can even help infer whether individual human participants
have formed an attentional set, which is crucial when applying the set-shifting task to
an evaluation of cognitive flexibility. Overall, this study demonstrates that the
Bayesian approach can yield additional information not available to the conventional
frequentist approach. Future work could include refining the rat Bayesian model and
the development of an adaptive trial design.
2018-06-29T00:00:00ZWang, JiachaoAttentional set-shifting tasks, consisting of multiple stages of discrimination learning,
have been widely used in animals and humans to investigate behavioural flexibility.
However, there are several learning criteria (e.g., 6-correct-choice-in-a-row, or 10-out-
of-12-correct) by which a subject might be judged to have learned a discrimination.
Furthermore, the currently frequentist approach does not provide a detailed analysis of
individual performance. In this PhD study, a large set of archival data of rats
performing a 7-stage intra-dimensional/extra-dimensional (ID/ED) attentional set-
shifting task was analysed, using a novel Bayesian analytical approach, to estimate
each rat’s learning processes over its trials within the task. The analysis showed that
the Bayesian learning criterion may be an appropriate alternative to the frequentist n-
correct-in-a-row criterion for studying performance. The individual analysis of rats’
behaviour using the Bayesian model also suggested that the rats responded according
to a number of irrelevant spatial and perceptual information sources before the correct
stimulus-reward association was established. The efficacy of the Bayesian analysis of
individual subjects’ behaviour and the appropriateness of the Bayesian learning
criterion were also supported by the analysis of simulated data in which the
behavioural choices in the task were generated by known rules. Additionally, the
efficacy was also supported by analysis of human behaviour during an analogous
human 7-stage attentional set-shifting task, where participants’ detailed learning
processes were collected based on their trial-by-trial oral report. Further, an extended
Bayesian approach, which considers the effects of feedback (correct vs incorrect) after
each response in the task, can even help infer whether individual human participants
have formed an attentional set, which is crucial when applying the set-shifting task to
an evaluation of cognitive flexibility. Overall, this study demonstrates that the
Bayesian approach can yield additional information not available to the conventional
frequentist approach. Future work could include refining the rat Bayesian model and
the development of an adaptive trial design.The assessment of behavioural deficits following focal cerebral ischemiaWard, Nicholas M.https://hdl.handle.net/10023/146982019-04-01T10:40:29Z1997-01-01T00:00:00ZEvaluating the efficacy of neuroprotective drugs in rat models of focal cerebral ischemia has involved histological and behavioural batteries to examine pathology and sensorimotor function. However, the behavioural tests used provide little insight into the nature of the neurological impairments. In an effort to gain further insight into the behavioural impairment following ischemic lesions, a battery of tasks were used. The tasks included tests of sensorimotor, motor (paw use), motivation, sensory and attentional function. The use of the potent vasoconstrictor endothelin-1 has allowed cerebral arteries to be occluded. This can be used to occlude the MCA (which is a common target of ischemia research), as well as other arteries, such as the ACA. Typically quantitative volumetric analysis has used nissl stains to assess lesion extent. However, alternative markers of tissue dysfunction are available including GFAP to assess the astroglial response to ischemia. Consequently cresyl violet and GFAP were compared along with different methods for calculating lesion volume. The boundaries of the lesion identified using the two stains corresponded closely providing care was taken when calculating lesion volume to avoid distortion from histological procedures and edema. Following MCA occlusion the rats displayed unilateral somatosensory and motor deficits, however there was no evidence of attentional dysfunction. Performance in the covert orienting task was compared with striatal dopamine depletion and with a posterior parietal cortical lesion. Neither of these manipulations resulted in deficits of covert orienting. Furthermore, the behavioural consequences of ACA occlusion were studied in two experiments using reaction time tasks designed to dissociate response impairments from dysfunction of motivation and attention. The ACA ischemic damage did not disrupt motivation or attention, however, the results were consistent with an impairment in selecting and initiating responses.
1997-01-01T00:00:00ZWard, Nicholas M.Evaluating the efficacy of neuroprotective drugs in rat models of focal cerebral ischemia has involved histological and behavioural batteries to examine pathology and sensorimotor function. However, the behavioural tests used provide little insight into the nature of the neurological impairments. In an effort to gain further insight into the behavioural impairment following ischemic lesions, a battery of tasks were used. The tasks included tests of sensorimotor, motor (paw use), motivation, sensory and attentional function. The use of the potent vasoconstrictor endothelin-1 has allowed cerebral arteries to be occluded. This can be used to occlude the MCA (which is a common target of ischemia research), as well as other arteries, such as the ACA. Typically quantitative volumetric analysis has used nissl stains to assess lesion extent. However, alternative markers of tissue dysfunction are available including GFAP to assess the astroglial response to ischemia. Consequently cresyl violet and GFAP were compared along with different methods for calculating lesion volume. The boundaries of the lesion identified using the two stains corresponded closely providing care was taken when calculating lesion volume to avoid distortion from histological procedures and edema. Following MCA occlusion the rats displayed unilateral somatosensory and motor deficits, however there was no evidence of attentional dysfunction. Performance in the covert orienting task was compared with striatal dopamine depletion and with a posterior parietal cortical lesion. Neither of these manipulations resulted in deficits of covert orienting. Furthermore, the behavioural consequences of ACA occlusion were studied in two experiments using reaction time tasks designed to dissociate response impairments from dysfunction of motivation and attention. The ACA ischemic damage did not disrupt motivation or attention, however, the results were consistent with an impairment in selecting and initiating responses.Event-related potential studies of explicit retrieval from memoryAllan, Kevinhttps://hdl.handle.net/10023/146962019-04-01T10:40:12Z1997-01-01T00:00:00ZIn six studies, Event-Related Potentials (ERPs) were employed to investigate the neural basis of conscious (explicit) retrieval from long term memory. The studies provide the first detailed reports of ERP effects associated with explicit retrieval on tests of word-stem (e.g. TRE) cued recall and stem completion. The relationship between the cued recall ERP effects and those previously observed on other tests of memory was also investigated. This was done by directly contrasting ERP correlates of explicit retrieval on the cued recall and recognition memory tasks. Two features of the cued recall and recognition memory ERP effects were found to be highly similar: ERP effects for each task were comprised of parietally and frontally distributed components which differed, as a function of task, only in two respects. First, the parietal effect for cued recall appeared to be somewhat delayed in onset latency relative to that for recognition memory. Second, the hemispheric asymmetry of the frontal effect for cued recall was less marked than that for recognition memory. The two ERP components were interpreted in terms of processes contributing to the recollection of previous episodes in which words were presented for study. A basic distinction between retrieval and post-retrieval processes was invoked to provide a functional account for the two components. The parietal component was related to retrieval processing associated with 'old/new' judgements. The frontal component was related to post-retrieval processing of retrieved information, which may be more under strategic control, and therefore sensitive to factors extrinsic to those affecting retrieval success per se. In conjunction with the findings of other ERP studies of long term memory, the present results suggest that similar electrophysiological and cognitive processes may be involved in retrieval and post-retrieval processing on a wide range of memory tasks. It is proposed that, under certain conditions, a common feature of these tasks may be the requirement to engage working memory, to monitor explicit retrieval processing.
1997-01-01T00:00:00ZAllan, KevinIn six studies, Event-Related Potentials (ERPs) were employed to investigate the neural basis of conscious (explicit) retrieval from long term memory. The studies provide the first detailed reports of ERP effects associated with explicit retrieval on tests of word-stem (e.g. TRE) cued recall and stem completion. The relationship between the cued recall ERP effects and those previously observed on other tests of memory was also investigated. This was done by directly contrasting ERP correlates of explicit retrieval on the cued recall and recognition memory tasks. Two features of the cued recall and recognition memory ERP effects were found to be highly similar: ERP effects for each task were comprised of parietally and frontally distributed components which differed, as a function of task, only in two respects. First, the parietal effect for cued recall appeared to be somewhat delayed in onset latency relative to that for recognition memory. Second, the hemispheric asymmetry of the frontal effect for cued recall was less marked than that for recognition memory. The two ERP components were interpreted in terms of processes contributing to the recollection of previous episodes in which words were presented for study. A basic distinction between retrieval and post-retrieval processes was invoked to provide a functional account for the two components. The parietal component was related to retrieval processing associated with 'old/new' judgements. The frontal component was related to post-retrieval processing of retrieved information, which may be more under strategic control, and therefore sensitive to factors extrinsic to those affecting retrieval success per se. In conjunction with the findings of other ERP studies of long term memory, the present results suggest that similar electrophysiological and cognitive processes may be involved in retrieval and post-retrieval processing on a wide range of memory tasks. It is proposed that, under certain conditions, a common feature of these tasks may be the requirement to engage working memory, to monitor explicit retrieval processing.Electrophysiological studies of formal, derivational and repetition primingDoyle, Michael Christopherhttps://hdl.handle.net/10023/146932019-04-01T10:41:09Z1996-01-01T00:00:00ZERPs have been found to be sensitive to formal (i.e. orthographic and phonological) and semantic relationships between words, as well as to word repetition. Such effects have been used to argue that the N400 component of the ERP may reflect processing of the representations of words, i.e. 'lexical processing'. If ERPs do reflect lexical processes then they may also be sensitive to morphological relationships between words which are thought to be lexically represented. The first three experiments investigated the sensitivity of ERPs to morphological relationships between words. Modulations of the ERP resulting from derivational, formal and repetition priming were compared. In each case, there was a positive-going shift in the ERP compared to the ERP elicited by unprimed words. However there was little evidence to suggest that the effects found in the derivational priming condition differed from those found when words were formally but not morphologically similar. A subsequent three experiments focused on these ERP formal priming effects. Formal priming effects were found when the proportion of related items was relatively low, with non-words and with words which were only orthographically similar and with words which were both orthographically and phonologically similar. In each case formal and repetition priming were initially of similar magnitude, with the repetition effect subsequently becoming greater in amplitude than the formal effect. Whilst the distribution of the repetition effect for non-words and the formal priming effects for words and non-words tended to be greatest over the right hemisphere, the word repetition effect was largest over the midline. It is concluded that the N400 does not reflect lexical processing, nor is it specific to semantic processing. Instead the N400 may reflect the operation of a similarity-sensitive mechanism which is sensitive to orthographic, phonological and/or semantic similarity and which may operate in an all-or-none fashion.
1996-01-01T00:00:00ZDoyle, Michael ChristopherERPs have been found to be sensitive to formal (i.e. orthographic and phonological) and semantic relationships between words, as well as to word repetition. Such effects have been used to argue that the N400 component of the ERP may reflect processing of the representations of words, i.e. 'lexical processing'. If ERPs do reflect lexical processes then they may also be sensitive to morphological relationships between words which are thought to be lexically represented. The first three experiments investigated the sensitivity of ERPs to morphological relationships between words. Modulations of the ERP resulting from derivational, formal and repetition priming were compared. In each case, there was a positive-going shift in the ERP compared to the ERP elicited by unprimed words. However there was little evidence to suggest that the effects found in the derivational priming condition differed from those found when words were formally but not morphologically similar. A subsequent three experiments focused on these ERP formal priming effects. Formal priming effects were found when the proportion of related items was relatively low, with non-words and with words which were only orthographically similar and with words which were both orthographically and phonologically similar. In each case formal and repetition priming were initially of similar magnitude, with the repetition effect subsequently becoming greater in amplitude than the formal effect. Whilst the distribution of the repetition effect for non-words and the formal priming effects for words and non-words tended to be greatest over the right hemisphere, the word repetition effect was largest over the midline. It is concluded that the N400 does not reflect lexical processing, nor is it specific to semantic processing. Instead the N400 may reflect the operation of a similarity-sensitive mechanism which is sensitive to orthographic, phonological and/or semantic similarity and which may operate in an all-or-none fashion.Event-related potential studies of explicit memory for associative informationDonaldson, David Ianhttps://hdl.handle.net/10023/146892019-04-01T10:41:06Z1998-01-01T00:00:00ZPrevious studies employing event related potentials (ERPs) have investigated the neural correlates of explicit memory using item recognition and source memory tests. These studies suggest that recollection, the retrieval of information about specific prior study episodes, is associated with two temporally and topographically dissociable ERP old/new effects. First, the 'left parietal' effect (found in studies of item and source memory) which provides an index of the retrieval processes supporting recollection. Second, the 'right frontal' effect (found in studies of source memory) which is thought to be associated with more strategic task-related 'post-retrieval' memory processes. In the present thesis the ERP old/new effects were investigated in five experiments using tests of explicit memory for associative information. In each experiment subjects studied novel word pairs, and memory for these associations was assessed using associative recognition and associative recall tasks. Consistent with previous behavioural studies that suggest associative recognition is dependent upon recollection, performance on this task was associated with both the left parietal and right frontal old/new effects. Moreover, successful associative recall was associated with equivalent old/new effects, contrary to previous findings that suggest performance on this task is associated with the left parietal but not the right frontal old/new effect. Whilst the findings support the previous functional account of the left parietal old/new effect, they necessitate the refinement of the account of the right frontal old/new effect. Significantly, the ERP findings suggest that the right frontal old/new effect can be dissociated from an early bilaterally-distributed frontal old/new effect that cannot be accounted for in terms of strategic post-retrieval processing. Finally, an alternative account of the frontal effects is proposed, drawing on evidence from neuroimaging studies, and distinguishing between pre- and post-retrieval support processes.
1998-01-01T00:00:00ZDonaldson, David IanPrevious studies employing event related potentials (ERPs) have investigated the neural correlates of explicit memory using item recognition and source memory tests. These studies suggest that recollection, the retrieval of information about specific prior study episodes, is associated with two temporally and topographically dissociable ERP old/new effects. First, the 'left parietal' effect (found in studies of item and source memory) which provides an index of the retrieval processes supporting recollection. Second, the 'right frontal' effect (found in studies of source memory) which is thought to be associated with more strategic task-related 'post-retrieval' memory processes. In the present thesis the ERP old/new effects were investigated in five experiments using tests of explicit memory for associative information. In each experiment subjects studied novel word pairs, and memory for these associations was assessed using associative recognition and associative recall tasks. Consistent with previous behavioural studies that suggest associative recognition is dependent upon recollection, performance on this task was associated with both the left parietal and right frontal old/new effects. Moreover, successful associative recall was associated with equivalent old/new effects, contrary to previous findings that suggest performance on this task is associated with the left parietal but not the right frontal old/new effect. Whilst the findings support the previous functional account of the left parietal old/new effect, they necessitate the refinement of the account of the right frontal old/new effect. Significantly, the ERP findings suggest that the right frontal old/new effect can be dissociated from an early bilaterally-distributed frontal old/new effect that cannot be accounted for in terms of strategic post-retrieval processing. Finally, an alternative account of the frontal effects is proposed, drawing on evidence from neuroimaging studies, and distinguishing between pre- and post-retrieval support processes.Using irrelevant pictures to investigate visual working memoryMcConnell, Jeanhttps://hdl.handle.net/10023/146882019-04-01T10:41:48Z1996-01-01T00:00:00ZExperiments 3 to 12 show that certain kinds of visuospatial material will differentially disrupt a visual memory strategy, even though subjects are instructed that the material is irrelevant. This irrelevant pictures effect is shown with a wide range of visual material including dynamic visual noise (Experiments 3 to 7 and 9 to 12), line drawings of common objects (Experiments 3 and 8), three by three matrices with the cells randomly black or white (Experiment 7) and a single dot that consecutively appears in five different positions in space (Experiment 12). The irrelevant pictures effect can also be demonstrated with two visual memory strategies that are qualitatively different from each other, the pegword mnemonic strategy and the method of loci strategy (Experiment 11). This robust irrelevant pictures effect is used as a tool for investigating visual working memory and the results of Experiments 1 to 12 are presented as being broadly consistent with Logie's 1995 two-component model of visual working memory comprising a visual cache and an inner scribe. The irrelevant pictures effect is evidence for the existence of the visual cache into which visual material is thought to have obligatory access. Experiment 9 demonstrates that static noise causes no interference with visual memory. Serially presented static noise in Experiment 10 does, however, selectively disrupt the visual strategy. It is hypothesised that the difference between the effect of the static pattern and the re-presented static pattern reflects the decay function of the visual cache. There is also support for the inner scribe part of the model. The star dots in Experiment 11 are thought to disrupt the pegword mnemonic strategy because both draw on common resources within the inner scribe. Moreover, Experiment 11 shows that the two components of Logie's 1995 model of visuospatial working memory can be empirically distinguished within one experiment. It shows that a visual task which requires access to the rehearsal component is disrupted by a concurrent, irrelevant spatial task as well as a concurrent, irrelevant visual task. In contrast, a visual task that requires little access to the rehearsal mechanism is not disrupted by a concurrent spatial task but is disrupted by a concurrent visual task. There are, however, also circumstances when the irrelevant visuospatial material disrupts visual and verbal memory strategies in a more general way, making attentional demands on the central executive part of working memory that are additional to those required to carry out the memory strategies. Three experiments look at this general effect of irrelevant pictures. Results suggest that the factors responsible for the placing of general demands on the central executive's attentional resources involve a focused, sufficiently unexpected change (Experiment 7) at the encoding stage of information processing (Experiment 8).
1996-01-01T00:00:00ZMcConnell, JeanExperiments 3 to 12 show that certain kinds of visuospatial material will differentially disrupt a visual memory strategy, even though subjects are instructed that the material is irrelevant. This irrelevant pictures effect is shown with a wide range of visual material including dynamic visual noise (Experiments 3 to 7 and 9 to 12), line drawings of common objects (Experiments 3 and 8), three by three matrices with the cells randomly black or white (Experiment 7) and a single dot that consecutively appears in five different positions in space (Experiment 12). The irrelevant pictures effect can also be demonstrated with two visual memory strategies that are qualitatively different from each other, the pegword mnemonic strategy and the method of loci strategy (Experiment 11). This robust irrelevant pictures effect is used as a tool for investigating visual working memory and the results of Experiments 1 to 12 are presented as being broadly consistent with Logie's 1995 two-component model of visual working memory comprising a visual cache and an inner scribe. The irrelevant pictures effect is evidence for the existence of the visual cache into which visual material is thought to have obligatory access. Experiment 9 demonstrates that static noise causes no interference with visual memory. Serially presented static noise in Experiment 10 does, however, selectively disrupt the visual strategy. It is hypothesised that the difference between the effect of the static pattern and the re-presented static pattern reflects the decay function of the visual cache. There is also support for the inner scribe part of the model. The star dots in Experiment 11 are thought to disrupt the pegword mnemonic strategy because both draw on common resources within the inner scribe. Moreover, Experiment 11 shows that the two components of Logie's 1995 model of visuospatial working memory can be empirically distinguished within one experiment. It shows that a visual task which requires access to the rehearsal component is disrupted by a concurrent, irrelevant spatial task as well as a concurrent, irrelevant visual task. In contrast, a visual task that requires little access to the rehearsal mechanism is not disrupted by a concurrent spatial task but is disrupted by a concurrent visual task. There are, however, also circumstances when the irrelevant visuospatial material disrupts visual and verbal memory strategies in a more general way, making attentional demands on the central executive part of working memory that are additional to those required to carry out the memory strategies. Three experiments look at this general effect of irrelevant pictures. Results suggest that the factors responsible for the placing of general demands on the central executive's attentional resources involve a focused, sufficiently unexpected change (Experiment 7) at the encoding stage of information processing (Experiment 8).Electrophysiological studies of memory for pictures and wordsSchloerscheidt, Astrid M.https://hdl.handle.net/10023/146862019-04-01T10:40:38Z1999-01-01T00:00:00ZThe retrieval of information from explicit memory has been associated with three temporally and topographically dissociable ERP correlates, an early bilateral and late right frontal component as well as a left parietal effect. The three studies in this thesis investigated that material-specificity of these ERP old/new effects to address the question whether the ERP correlates of memory retrieval vary according to the nature of the information that is retrieved. The studies compared the ERP correlates for retrieval of pictures and words, when presented in the same modality at study and test and when presented across modalities (i.e., words at study - pictures at test or vice versa) in the two phases. Results provided little evidence for the engagement of different neural generators for the retrieval of the different types of stimuli. The topographic differences that emerged, suggested the engagement of a common set of generators activated at different levels and with a different time-course, depending on the type of encoding stimulus and retrieval cue. However, the results did provide further evidence regarding the functional interpretations of the established old/new effects. All experimental conditions revealed a left parietal effect which was largest when the encoding stimuli were presented in pictorial form. Given that the rich perceptual information inherent in pictures leads to a greater incidence of episodic retrieval for pictures (picture superiority effect) the current finding provides further support for the functional interpretation of this effect as the neural correlate of recollection. All experimental conditions also revealed a late right frontal effect which showed no differences in magnitude or topography between the different conditions. This insensitivity to the type of encoded material and the type of retrieval cue supports the interpretation of the effect as the neural correlate of post-retrieval monitoring processes. New functional properties of the early bilateral frontal effect emerged. The effect was only present when stimuli were presented in the same modality at study and test. Thus, the effect appears to be highly sensitive to the perceptual similarity of an item between study and test, which suggests a functional correlation to perceptual data-driven processes, proposed to be one of the bases of familiarity-driven recognition.
1999-01-01T00:00:00ZSchloerscheidt, Astrid M.The retrieval of information from explicit memory has been associated with three temporally and topographically dissociable ERP correlates, an early bilateral and late right frontal component as well as a left parietal effect. The three studies in this thesis investigated that material-specificity of these ERP old/new effects to address the question whether the ERP correlates of memory retrieval vary according to the nature of the information that is retrieved. The studies compared the ERP correlates for retrieval of pictures and words, when presented in the same modality at study and test and when presented across modalities (i.e., words at study - pictures at test or vice versa) in the two phases. Results provided little evidence for the engagement of different neural generators for the retrieval of the different types of stimuli. The topographic differences that emerged, suggested the engagement of a common set of generators activated at different levels and with a different time-course, depending on the type of encoding stimulus and retrieval cue. However, the results did provide further evidence regarding the functional interpretations of the established old/new effects. All experimental conditions revealed a left parietal effect which was largest when the encoding stimuli were presented in pictorial form. Given that the rich perceptual information inherent in pictures leads to a greater incidence of episodic retrieval for pictures (picture superiority effect) the current finding provides further support for the functional interpretation of this effect as the neural correlate of recollection. All experimental conditions also revealed a late right frontal effect which showed no differences in magnitude or topography between the different conditions. This insensitivity to the type of encoded material and the type of retrieval cue supports the interpretation of the effect as the neural correlate of post-retrieval monitoring processes. New functional properties of the early bilateral frontal effect emerged. The effect was only present when stimuli were presented in the same modality at study and test. Thus, the effect appears to be highly sensitive to the perceptual similarity of an item between study and test, which suggests a functional correlation to perceptual data-driven processes, proposed to be one of the bases of familiarity-driven recognition.Recognition memory with and without retrieval of context: studies with event-related potentialsWilding, Edward L.https://hdl.handle.net/10023/146842019-04-01T10:41:47Z1996-01-01T00:00:00ZIn six experiments event-related potentials (ERPs) were recorded while subjects performed modified recognition memory tests. All experiments consisted of an initial study phase in which subjects studied words which were presented in one of two contexts. In a subsequent test phase subjects discriminated between old and new items, and between old items which had been presented in one of the two contexts at study. The design of these experiments permitted a comparison of three critical classes of ERPs: those to words correctly judged new, and those to words correctly judged old which were either correctly or incorrectly assigned to study context. All six experiments revealed reliable differences between the ERPs to correctly identified old and new words. In experiments 3-6 the analyses of the differences between the ERPs to correctly identified old and new words revealed two topographically and temporally dissociable modulations. The first of these was maximal at parietal sites over the 500-900 msec time window, and was larger over the left hemisphere than over the right. The second modulation was more temporally extended, maximal at frontal scalp locations, and displayed a right-greater than-left hemisphere asymmetry. Both of these modulations were of greater magnitude for words which were correctly assigned to study context. These findings are consistent with the view that multiple neural systems contribute to memory for context. The experimental findings are discussed in relation to theories of the relationship between memory for prior occurrences, and memory for contextual details of those occurrences.
1996-01-01T00:00:00ZWilding, Edward L.In six experiments event-related potentials (ERPs) were recorded while subjects performed modified recognition memory tests. All experiments consisted of an initial study phase in which subjects studied words which were presented in one of two contexts. In a subsequent test phase subjects discriminated between old and new items, and between old items which had been presented in one of the two contexts at study. The design of these experiments permitted a comparison of three critical classes of ERPs: those to words correctly judged new, and those to words correctly judged old which were either correctly or incorrectly assigned to study context. All six experiments revealed reliable differences between the ERPs to correctly identified old and new words. In experiments 3-6 the analyses of the differences between the ERPs to correctly identified old and new words revealed two topographically and temporally dissociable modulations. The first of these was maximal at parietal sites over the 500-900 msec time window, and was larger over the left hemisphere than over the right. The second modulation was more temporally extended, maximal at frontal scalp locations, and displayed a right-greater than-left hemisphere asymmetry. Both of these modulations were of greater magnitude for words which were correctly assigned to study context. These findings are consistent with the view that multiple neural systems contribute to memory for context. The experimental findings are discussed in relation to theories of the relationship between memory for prior occurrences, and memory for contextual details of those occurrences.An investigation into the nature of perceptual style and body awareness in relation to perceptual-motor abilitiesHead, Andrew S.https://hdl.handle.net/10023/146832019-04-01T10:41:05Z1988-01-01T00:00:00ZThe thesis is an account of an investigative study into the nature of perceptual-motor abilities. Part one considers Witkin's construct of cognitive style, using it to predict the relationships between three tests of perceptual functioning from widely varying areas of psychology and sports science. To some extent the results were as predicted; that is, those people demonstrating high levels of perceptual acuity on one test also showed similar acuity on one or more of the other perceptual tests. These results, however, only applied to the male subjects and then only when the opposite poles of one test-dimension were partitioned out and compared. The female subjects demonstrated no significant relationships between the three tests. As a result, it was proposed that the tests were indeed linked but by an array of underlying perceptual abilities rather than by a single, overlying cognitive or perceptual style. In the ensuing search for these abilities, 76 measures of perceptual and perceptual-motor skills were factor analysed to reveal 8 oblique perceptual-motor factors of which one was interpreted as being perceptual style. The nature of perceptual-motor abilities is discussed both in relation to clumsiness and to sports training with the emphasis being on whether such abilities are amenable to alteration. The thesis puts forward the proposal that an upper limit to each ability is fixed for each individual in early childhood but that this potential may be maximised through relevant training. The Perceptual-Motor Ability Profile was devised as a tool with which to indicate the aptitude a person evidenced for a particular sport or physical activity and was used in demonstration to describe the group abilities of four dancers with respect to the requirements of their chosen activity. Finally, a model of perceptual-motor functioning, relating the eight factors extracted, is suggested.
1988-01-01T00:00:00ZHead, Andrew S.The thesis is an account of an investigative study into the nature of perceptual-motor abilities. Part one considers Witkin's construct of cognitive style, using it to predict the relationships between three tests of perceptual functioning from widely varying areas of psychology and sports science. To some extent the results were as predicted; that is, those people demonstrating high levels of perceptual acuity on one test also showed similar acuity on one or more of the other perceptual tests. These results, however, only applied to the male subjects and then only when the opposite poles of one test-dimension were partitioned out and compared. The female subjects demonstrated no significant relationships between the three tests. As a result, it was proposed that the tests were indeed linked but by an array of underlying perceptual abilities rather than by a single, overlying cognitive or perceptual style. In the ensuing search for these abilities, 76 measures of perceptual and perceptual-motor skills were factor analysed to reveal 8 oblique perceptual-motor factors of which one was interpreted as being perceptual style. The nature of perceptual-motor abilities is discussed both in relation to clumsiness and to sports training with the emphasis being on whether such abilities are amenable to alteration. The thesis puts forward the proposal that an upper limit to each ability is fixed for each individual in early childhood but that this potential may be maximised through relevant training. The Perceptual-Motor Ability Profile was devised as a tool with which to indicate the aptitude a person evidenced for a particular sport or physical activity and was used in demonstration to describe the group abilities of four dancers with respect to the requirements of their chosen activity. Finally, a model of perceptual-motor functioning, relating the eight factors extracted, is suggested.Variable processing of flavours in rat STMRobertson, Derekhttps://hdl.handle.net/10023/146822019-04-01T10:41:29Z1985-01-01T00:00:00ZThe research reported in this thesis examines factors that affect the willingness of rats to ingest novel flavour solutions. Emphasis is placed on the memorial processes assumed to underlie the decision as to whether or not a solution is "safe" to drink. Rats exhibit caution (neophobia) in consuming an unfamiliar (target) solution. This unconditional response to novelty habituates as the rat acquires experience with the target solution (provided that ingestion of the target solution has no noxious consequences!). Neophobia to the target solution may be restored, however, if another (distractor) solution is presented during the interval separating pre-exposure to, and testing of, the target solution (Green & Parker, 1975). In Section 1, the phenomena of habituation to an iterated target stimulus and the disruption of this process by a distractor are introduced. Theoretical explanations of the "dishabituation" effect of a distractor stimulus are described and assessed. The possibility of an empirical test of the relative validity of the Robertson and the Wagner hypotheses using the attenuation of flavour neophobia procedure of Green and Parker provided the impetus for the experiments reported in Section 2. In Section 3, attention is drawn to the similarity of the procedure designed to establish habituation and that Intended to establish latent inhibition to a stimulus. A limited review of empirical data is presented testifying to the fact that habituation and latent inhibition are affected similarly by identical parameter manipulations. The Wagner (1976) model views habituation and latent inhibition as the outcome of a common underlying process, Expts. 10a and 10b, therefore, sought to determine whether latent inhibition of a conditioned taste aversion (CTA) to lemon or sucrose solution would be affected by a coffee distractor in a manner consonant with predictions derived from the results of the neophobia experiments reported in Section 2. The distractor, however, had no effect on strength of latent inhibition in either experiment. Expt. 11c demonstrated that it is possible for a distractor (30% vanilla) to disrupt attenuation of neophobia to a target flavour (3% cider vinegar) without affecting latent inhibition to the target flavour, i.e., there is no direct correspondence between measures of habituation and latent inhibition to the same stimulus. In Section 4, the phenomena of overshadowing and potentiation of a CTA are introduced. At least one explanation of potentiation (c.f., Durlach & Rescorla, 1980) stresses the importance of an association between the elements of a compound CS. Rescorla and Furrow (1977) found interstimulus associations were formed more rapidly between similar rather than dissimilar stimuli. Given these results, Expts. 12a and 12b sought to determine whether a single sequential presentation of lemon and coffee (similar solutions) paired with LiCl would result in potentiation of a conditioned aversion to the lemon solution and whether a single sequential presentation of sucrose and coffee (dissimilar solutions) paired with LiCl would result in overshadowing of a conditioned aversion to the sucrose solution. These experimental predictions were confirmed. In Section 5, a potential confound in the neophobia experiments is addressed. Interpretation of attenuated neophobia as a habituation process is defended and alternatives to the Wagner (1976) theory of habituation are considered for their ability to encompass the data reported in Section 2. Only the Wagner model, however, appears able to account for all the data. Nevertheless, some limitations of the model are indicated. Finally, the conditions promoting overshadowing and potentiation of a CTA are discussed. (Abstract shortened by ProQuest.)
1985-01-01T00:00:00ZRobertson, DerekThe research reported in this thesis examines factors that affect the willingness of rats to ingest novel flavour solutions. Emphasis is placed on the memorial processes assumed to underlie the decision as to whether or not a solution is "safe" to drink. Rats exhibit caution (neophobia) in consuming an unfamiliar (target) solution. This unconditional response to novelty habituates as the rat acquires experience with the target solution (provided that ingestion of the target solution has no noxious consequences!). Neophobia to the target solution may be restored, however, if another (distractor) solution is presented during the interval separating pre-exposure to, and testing of, the target solution (Green & Parker, 1975). In Section 1, the phenomena of habituation to an iterated target stimulus and the disruption of this process by a distractor are introduced. Theoretical explanations of the "dishabituation" effect of a distractor stimulus are described and assessed. The possibility of an empirical test of the relative validity of the Robertson and the Wagner hypotheses using the attenuation of flavour neophobia procedure of Green and Parker provided the impetus for the experiments reported in Section 2. In Section 3, attention is drawn to the similarity of the procedure designed to establish habituation and that Intended to establish latent inhibition to a stimulus. A limited review of empirical data is presented testifying to the fact that habituation and latent inhibition are affected similarly by identical parameter manipulations. The Wagner (1976) model views habituation and latent inhibition as the outcome of a common underlying process, Expts. 10a and 10b, therefore, sought to determine whether latent inhibition of a conditioned taste aversion (CTA) to lemon or sucrose solution would be affected by a coffee distractor in a manner consonant with predictions derived from the results of the neophobia experiments reported in Section 2. The distractor, however, had no effect on strength of latent inhibition in either experiment. Expt. 11c demonstrated that it is possible for a distractor (30% vanilla) to disrupt attenuation of neophobia to a target flavour (3% cider vinegar) without affecting latent inhibition to the target flavour, i.e., there is no direct correspondence between measures of habituation and latent inhibition to the same stimulus. In Section 4, the phenomena of overshadowing and potentiation of a CTA are introduced. At least one explanation of potentiation (c.f., Durlach & Rescorla, 1980) stresses the importance of an association between the elements of a compound CS. Rescorla and Furrow (1977) found interstimulus associations were formed more rapidly between similar rather than dissimilar stimuli. Given these results, Expts. 12a and 12b sought to determine whether a single sequential presentation of lemon and coffee (similar solutions) paired with LiCl would result in potentiation of a conditioned aversion to the lemon solution and whether a single sequential presentation of sucrose and coffee (dissimilar solutions) paired with LiCl would result in overshadowing of a conditioned aversion to the sucrose solution. These experimental predictions were confirmed. In Section 5, a potential confound in the neophobia experiments is addressed. Interpretation of attenuated neophobia as a habituation process is defended and alternatives to the Wagner (1976) theory of habituation are considered for their ability to encompass the data reported in Section 2. Only the Wagner model, however, appears able to account for all the data. Nevertheless, some limitations of the model are indicated. Finally, the conditions promoting overshadowing and potentiation of a CTA are discussed. (Abstract shortened by ProQuest.)The orienting of auditory attention: event-related potential investigationsHoldstock, Juliet Sarahttps://hdl.handle.net/10023/146782019-04-01T10:42:16Z1993-01-01T00:00:00ZThe P300 complex has been dissociated into a parietally maximal P3b and a more anteriorly distributed P3a in auditory, visual and somatosensory modalities. The seven experiments reported in this thesis investigate the variables affecting the elicitation of the P3a. The Knight et al. (1989) paradigm was used which involves the presentation of frequent, rare target and rare nontarget auditory stimuli. Experiment 1 showed that the P3a was elicited by novel sounds (environmental noises) when presented as rare nontargets in a sequence of frequent and target tones. When the rare nontarget novel sounds were presented in a sequence of other novel sounds the P3a was not elicited (Experiment 2). Experiment 3 showed that making the rare novel sound a target abolished the P3a, as did omitting the frequent stimuli from the sequence (Experiment 4). In the experiments in which the P3a was abolished, the novel sounds were found to elicit a P300 deflection with a parietally maximal scalp distribution (P3b). Other experiments showed no indication of habituation of the P3a over subsequent stimulus presentations (experiment 6) but did show that the amplitude of the P3a was larger when preceded by several stimuli different to the eliciting novel sound, than when immediately preceded by the identical sound (experiment 7). In contrast to novel sounds, tones did not elicit a P3a, even when presented as rare nontargets among frequent and target novel sounds (experiment 5). The findings were related to a recent model of auditory attention (Naatanen, 1990). The P3a was interpreted as reflecting a process related to the orienting of attention resulting from the detection of a mismatch between present and previous stimuli.
1993-01-01T00:00:00ZHoldstock, Juliet SaraThe P300 complex has been dissociated into a parietally maximal P3b and a more anteriorly distributed P3a in auditory, visual and somatosensory modalities. The seven experiments reported in this thesis investigate the variables affecting the elicitation of the P3a. The Knight et al. (1989) paradigm was used which involves the presentation of frequent, rare target and rare nontarget auditory stimuli. Experiment 1 showed that the P3a was elicited by novel sounds (environmental noises) when presented as rare nontargets in a sequence of frequent and target tones. When the rare nontarget novel sounds were presented in a sequence of other novel sounds the P3a was not elicited (Experiment 2). Experiment 3 showed that making the rare novel sound a target abolished the P3a, as did omitting the frequent stimuli from the sequence (Experiment 4). In the experiments in which the P3a was abolished, the novel sounds were found to elicit a P300 deflection with a parietally maximal scalp distribution (P3b). Other experiments showed no indication of habituation of the P3a over subsequent stimulus presentations (experiment 6) but did show that the amplitude of the P3a was larger when preceded by several stimuli different to the eliciting novel sound, than when immediately preceded by the identical sound (experiment 7). In contrast to novel sounds, tones did not elicit a P3a, even when presented as rare nontargets among frequent and target novel sounds (experiment 5). The findings were related to a recent model of auditory attention (Naatanen, 1990). The P3a was interpreted as reflecting a process related to the orienting of attention resulting from the detection of a mismatch between present and previous stimuli.Electrophysiological studies on the optics of the compound eyeTunstall, Johnhttps://hdl.handle.net/10023/146762020-11-26T03:05:18Z1967-01-01T00:00:00Z1. Intracellular recordings from single retinula cells in the locust compound eye show that the visual field of a single cell is wider in dark-adapted than in light-adapted eyes. 2. The time course of the increase in the visual field of a single cell is correlated with the replacement of a dense packing of mitochondria by a fluid filled palisade around the rhabdom during dark-adaptation. 3. The development of the palisade results in a reduction of the refractive index immediately around the rhabdom. 4. The correlation between the increase in the visual field of a single cell and the development of the palisade is evidence for internal reflection in the rhabdom. 5. Direct tests of the acuity of single retinula cells to equal black and white stripes of various repeat distances show reasonable agreement with theoretical considerations based upon Gaussian acceptance curves, and is dependent upon the state of adaptation of the eye.
1967-01-01T00:00:00ZTunstall, John1. Intracellular recordings from single retinula cells in the locust compound eye show that the visual field of a single cell is wider in dark-adapted than in light-adapted eyes. 2. The time course of the increase in the visual field of a single cell is correlated with the replacement of a dense packing of mitochondria by a fluid filled palisade around the rhabdom during dark-adaptation. 3. The development of the palisade results in a reduction of the refractive index immediately around the rhabdom. 4. The correlation between the increase in the visual field of a single cell and the development of the palisade is evidence for internal reflection in the rhabdom. 5. Direct tests of the acuity of single retinula cells to equal black and white stripes of various repeat distances show reasonable agreement with theoretical considerations based upon Gaussian acceptance curves, and is dependent upon the state of adaptation of the eye.Spectral properties of dark-adapted plaice retinal ganglion cellsHammond, Peterhttps://hdl.handle.net/10023/146502019-04-01T10:40:53Z1967-01-01T00:00:00Z1. The spectral, spatial and temporal properties of receptive fields of dark-adapted, on-off retinal ganglion cells in the intact eye of the plaice, have been analysed by recording responses from their axon terminals in the superficial layers of the contra-lateral optic tectum with indium micro-electrodes. 2 Two cell-types have been identified on criteria of discharge patterns. The first type gives spectrally opponent "on-off" responses to coloured stimuli, with no subdivision of receptive fields into centre and periphery. On and "off" response-components are mutually inhibitory. The second type gives slow-adapting, "on-off" or "off" responses for different stimulus positions within the receptive field, with centre-surround or adjacent field patterns. Only "on-off" centre, off"-surround cells, or "off"-centre, "on-off" surround cells have been found, "On-off" centre cells exhibit mutual antagonism between field centre and surround. "Off"-centre cells possess inhibitory centres. This cell-type gives only weak opponent, or possibly non-opponent responses. 3. Moot cells of each type receive rod input in addition to input from cones. At stimulus intensities suprathreshold for cones, response-components give spectral maxima or more of four wavelength ranges; blue, 440-460 mum; blue-green, 470-490 mum; green, 510-540 mum; and orange, 560-590 mum. No cello give red sensitivity maxima. At low stimulus intensities all cells with rod input give a single spectral peak between 520 and 530 mum.
1967-01-01T00:00:00ZHammond, Peter1. The spectral, spatial and temporal properties of receptive fields of dark-adapted, on-off retinal ganglion cells in the intact eye of the plaice, have been analysed by recording responses from their axon terminals in the superficial layers of the contra-lateral optic tectum with indium micro-electrodes. 2 Two cell-types have been identified on criteria of discharge patterns. The first type gives spectrally opponent "on-off" responses to coloured stimuli, with no subdivision of receptive fields into centre and periphery. On and "off" response-components are mutually inhibitory. The second type gives slow-adapting, "on-off" or "off" responses for different stimulus positions within the receptive field, with centre-surround or adjacent field patterns. Only "on-off" centre, off"-surround cells, or "off"-centre, "on-off" surround cells have been found, "On-off" centre cells exhibit mutual antagonism between field centre and surround. "Off"-centre cells possess inhibitory centres. This cell-type gives only weak opponent, or possibly non-opponent responses. 3. Moot cells of each type receive rod input in addition to input from cones. At stimulus intensities suprathreshold for cones, response-components give spectral maxima or more of four wavelength ranges; blue, 440-460 mum; blue-green, 470-490 mum; green, 510-540 mum; and orange, 560-590 mum. No cello give red sensitivity maxima. At low stimulus intensities all cells with rod input give a single spectral peak between 520 and 530 mum.The neurophysiology of form and motion processing in the temporal lobe of the macaque monkeyOram, Mike W.https://hdl.handle.net/10023/146492019-04-01T10:41:32Z1995-01-01T00:00:00ZConsideration of available evidence suggests that primate vision utilises two parallel cortical pathways to process visual information. The ventral pathway processes form or shape information, while the dorsal pathway processes motion information. In the macaque monkey, the superior temporal sulcus in the temporal lobe is one of the few cortical areas that receives input from both these pathways. In this thesis recordings from visually responsive neurons in the macaque superior temporal sulcus are described. The cell response properties of three cell groups are investigated. One cell population show selectivity for the sight of static images of particular views of the body. The second group of cells shows selectivity for the sight of objects moving in the environment, independent of the object's form. The final group of cells show selectivity for particular views of the body providing that they are moving in particular directions. The responses from these three groups of cell types are subjected to an analysis technique that allows insights into possible computational processes underlying the observed neural selectivity's. In particular, it is argued that the primate visual system processes form information primarily in a feedforward way, a property few computational models of visual processing employ. These data are combined with data from other studies to produce a speculative outline for a biologically plausible model of primate visual form processing. The recordings also revealed cell responses to walking bodies that showed a remarkable selectivity for "structure from motion". It is suggested that this selectivity is developed by associative learning between the initially separate form and motion inputs. Investigation of the integration of form and motion information onto single cells indicated a hitherto unforeseen problem: a temporal asynchrony between the arrival times of form and direction information. This asynchrony indicates that previously proposed mechanisms for binding of information about the same object are incorrect.
1995-01-01T00:00:00ZOram, Mike W.Consideration of available evidence suggests that primate vision utilises two parallel cortical pathways to process visual information. The ventral pathway processes form or shape information, while the dorsal pathway processes motion information. In the macaque monkey, the superior temporal sulcus in the temporal lobe is one of the few cortical areas that receives input from both these pathways. In this thesis recordings from visually responsive neurons in the macaque superior temporal sulcus are described. The cell response properties of three cell groups are investigated. One cell population show selectivity for the sight of static images of particular views of the body. The second group of cells shows selectivity for the sight of objects moving in the environment, independent of the object's form. The final group of cells show selectivity for particular views of the body providing that they are moving in particular directions. The responses from these three groups of cell types are subjected to an analysis technique that allows insights into possible computational processes underlying the observed neural selectivity's. In particular, it is argued that the primate visual system processes form information primarily in a feedforward way, a property few computational models of visual processing employ. These data are combined with data from other studies to produce a speculative outline for a biologically plausible model of primate visual form processing. The recordings also revealed cell responses to walking bodies that showed a remarkable selectivity for "structure from motion". It is suggested that this selectivity is developed by associative learning between the initially separate form and motion inputs. Investigation of the integration of form and motion information onto single cells indicated a hitherto unforeseen problem: a temporal asynchrony between the arrival times of form and direction information. This asynchrony indicates that previously proposed mechanisms for binding of information about the same object are incorrect.Coding of object parts, view, orientation and size in the temporal cortex of the macaqueWachsmuth, Elisabethhttps://hdl.handle.net/10023/146472019-04-01T10:41:43Z1996-01-01T00:00:00ZThe study examined the importance of (1) component parts, (2) view, (3) orientation and (4) size in the neural encoding of the sight of a complex object in the temporal cortex of the macaque. Studies focused on cells selectively responsive to the sight of the head/body but unresponsive to control stimuli. (1) Cells responsive to the static whole body were tested with two component parts of the body. 44% (29/66) of cells responded to the whole body and to one of the two body regions tested: 23 to the head; 6 to the body. 36% (24/66) responded independently to both regions of the body when tested in isolation. The remaining cells were selective for the entire body and unresponsive to component parts. Similar selectivity for component parts was observed amongst cells responsive to moving heads/bodies (18 cells tested). (2) 90% (66/73) of cells (selectively responsive to static or moving head/bodies) tested were sensitive to perspective view (viewer-centred). Comparable levels of view sensitivity were found for responses to the whole body and its parts. Contrary to some influential models of object recognition these results indicate view-specific processing for both the appearance of separate object components and for integration of information across components. (3) The majority of cells tested (18/25, 72%) were selectively responsive to a particular orientation in the picture plane of the static whole body stimulus. 7 cells generalised across all orientations (4 cell with pure generalisation; 3 cells with superimposed orientation tuning). Of all cells sensitive to orientation, the majority (15/21, 71%) were tuned to the upright image. (4) The majority of cells tested (81%, 13/16) were selective for a particular stimulus size. The remaining cells (3/16) showed generalisation across a 4 fold decrease in size from life-sized. Interestingly, all size sensitive cells were tuned to life-sized stimuli. These results do not support previous suggestions that cells responsive to the head and body are selective to the view but generalise across orientation and size. Here, extensive selectivity for size and orientation is reported. It is suggested that object part, view, orientation and size specific responses might be pooled to obtain generalising responses. Experience appears to affect neuronal coding in two ways: a) Cells become selective for multiple object components due to spatial and temporal association between parts; and b) more cells become tuned to views, orientations and image sizes commonly experienced.
1996-01-01T00:00:00ZWachsmuth, ElisabethThe study examined the importance of (1) component parts, (2) view, (3) orientation and (4) size in the neural encoding of the sight of a complex object in the temporal cortex of the macaque. Studies focused on cells selectively responsive to the sight of the head/body but unresponsive to control stimuli. (1) Cells responsive to the static whole body were tested with two component parts of the body. 44% (29/66) of cells responded to the whole body and to one of the two body regions tested: 23 to the head; 6 to the body. 36% (24/66) responded independently to both regions of the body when tested in isolation. The remaining cells were selective for the entire body and unresponsive to component parts. Similar selectivity for component parts was observed amongst cells responsive to moving heads/bodies (18 cells tested). (2) 90% (66/73) of cells (selectively responsive to static or moving head/bodies) tested were sensitive to perspective view (viewer-centred). Comparable levels of view sensitivity were found for responses to the whole body and its parts. Contrary to some influential models of object recognition these results indicate view-specific processing for both the appearance of separate object components and for integration of information across components. (3) The majority of cells tested (18/25, 72%) were selectively responsive to a particular orientation in the picture plane of the static whole body stimulus. 7 cells generalised across all orientations (4 cell with pure generalisation; 3 cells with superimposed orientation tuning). Of all cells sensitive to orientation, the majority (15/21, 71%) were tuned to the upright image. (4) The majority of cells tested (81%, 13/16) were selective for a particular stimulus size. The remaining cells (3/16) showed generalisation across a 4 fold decrease in size from life-sized. Interestingly, all size sensitive cells were tuned to life-sized stimuli. These results do not support previous suggestions that cells responsive to the head and body are selective to the view but generalise across orientation and size. Here, extensive selectivity for size and orientation is reported. It is suggested that object part, view, orientation and size specific responses might be pooled to obtain generalising responses. Experience appears to affect neuronal coding in two ways: a) Cells become selective for multiple object components due to spatial and temporal association between parts; and b) more cells become tuned to views, orientations and image sizes commonly experienced.Polarized light detection and receptor interaction in the arthropod eyeShaw, Stephen Rodneyhttps://hdl.handle.net/10023/146032019-04-01T10:42:08Z1968-01-01T00:00:00Z1968-01-01T00:00:00ZShaw, Stephen RodneyThe nervous control of the eye movements of the shore crab Carcinus maenasSandeman, D. C.https://hdl.handle.net/10023/146012019-04-01T10:41:37Z1964-01-01T00:00:00Z1. The eyes of the crab Carcinus follow with constantly increasing lag the movement of a horizontally rotating (but not a linearly translated) visual field during the slow phase of optokinetic nystagmus. The difference between the eye speed and the drum speed is the effective stimulus for optokinetic nystagmus, and the response bears a constant relation to the stimulus over four orders of magnitude. The lower limit of the response is due to the breakdown of neuromuscular, and not visual mechanism. 2. An overall feedback mechanism exists in which the movement of the eye reduces the apparent movement of the drum. The control of the eye movement is by way of visual cues and proprioceptors play no part. 3. A seeing eye, provided with the appropriate visual stimulus, will drive the other eye if the latter sees no contrasting objects in its visual field or is blinded. Clamping an eye so that it cannot move relative to a stationary, contrasting visual field has the same effect as surrounding the animal with a blank field. 4. The rapid return phase of optokinetic nystagmus also takes no account of proprioceptors, but seems to be triggered when the efferent impulses to the eye muscles reach a definite frequency. Blinding one eye or increasing the drum speed cause a delay of the fast phase. Both eyes flick back simultaneously and the impulses in the oculomotor nerve which cause the slow phase are inhibited during the fast phase. 5. The fast protective retraction of the eye into its socket is a reflex which can be elicited by mechanical stimulation of a single sensory hair. The eyes can retract independently and if retraction occurs during the slow phase of optokinetic nystagmus, the efferent impulses in the oculomotor nerve of the retracting side are centrally suppressed. Peripheral inhibition of the optokinetic response occurs in the retracted eye when it. Is retained in its socket after retraction while the other eye continues with the slow phase of optokinetic nystagmus.7. A comparison reveals similarities in the mechanism causing the onset of the fast phase of optokinetic nystagmus in the crab and in mammals.
1964-01-01T00:00:00ZSandeman, D. C.1. The eyes of the crab Carcinus follow with constantly increasing lag the movement of a horizontally rotating (but not a linearly translated) visual field during the slow phase of optokinetic nystagmus. The difference between the eye speed and the drum speed is the effective stimulus for optokinetic nystagmus, and the response bears a constant relation to the stimulus over four orders of magnitude. The lower limit of the response is due to the breakdown of neuromuscular, and not visual mechanism. 2. An overall feedback mechanism exists in which the movement of the eye reduces the apparent movement of the drum. The control of the eye movement is by way of visual cues and proprioceptors play no part. 3. A seeing eye, provided with the appropriate visual stimulus, will drive the other eye if the latter sees no contrasting objects in its visual field or is blinded. Clamping an eye so that it cannot move relative to a stationary, contrasting visual field has the same effect as surrounding the animal with a blank field. 4. The rapid return phase of optokinetic nystagmus also takes no account of proprioceptors, but seems to be triggered when the efferent impulses to the eye muscles reach a definite frequency. Blinding one eye or increasing the drum speed cause a delay of the fast phase. Both eyes flick back simultaneously and the impulses in the oculomotor nerve which cause the slow phase are inhibited during the fast phase. 5. The fast protective retraction of the eye into its socket is a reflex which can be elicited by mechanical stimulation of a single sensory hair. The eyes can retract independently and if retraction occurs during the slow phase of optokinetic nystagmus, the efferent impulses in the oculomotor nerve of the retracting side are centrally suppressed. Peripheral inhibition of the optokinetic response occurs in the retracted eye when it. Is retained in its socket after retraction while the other eye continues with the slow phase of optokinetic nystagmus.7. A comparison reveals similarities in the mechanism causing the onset of the fast phase of optokinetic nystagmus in the crab and in mammals.Remembering past events in chimpanzees (Pan troglodytes), bonobos (Pan paniscus) and orangutans (Pongo pygmaeus)Lewis, Amy Victoria Maryhttps://hdl.handle.net/10023/146002023-04-12T08:28:36Z2018-06-29T00:00:00ZEpisodic memory is memory for personally experienced past events. Recently, there has been intense debate as to whether episodic memory is unique to humans, or whether it may extend to non-human animals. Although many insightful paradigms have shown elements of episodic memory in numerous species, research has been shrouded with difficulties, stemming from the extensive criteria and the phenomenological nature of such memories. This thesis, therefore, aims to move beyond a debate hindered by definition, and rather than searching for a definite answer to the question, focuses on comparing the similarities and differences between the way humans and animals (specifically, great apes) recall past events.
The thesis beings with an introduction to memory, before focusing on episodic memory and the episodic memory debate. In the following chapter, the subjects (great apes) and the general testing procedure are introduced. In Chapter 3, the distinctiveness effect is investigated in the recall of a past event. The distinctiveness effect refers to the enhanced memory for distinctive, as opposed to non-distinct information. The results suggest that the distinctiveness effect occurs in great apes’ memory of past events, moreover, it occurs regardless of reinforcement, consistent with results found in humans. Chapter 4 explores involuntary memory in great apes; a form of memory that occurs frequently in humans and has been proposed to exist in animals, yet has been largely overlooked. Using a paradigm that draws upon elements of involuntary memory, apes show successful recall of a past event after long delays. Chapter 5 investigates the recall of social information from past events, an area which has received little attention. The results of this chapter indicate that apes fail to integrate social information (who) with what, suggesting that social information may not be readily incorporated into the memory of past events; however, this is likely due to a lack of saliency. The final chapter discusses the findings of the three experimental chapters (3-5), before providing potential avenues for future research.
2018-06-29T00:00:00ZLewis, Amy Victoria MaryEpisodic memory is memory for personally experienced past events. Recently, there has been intense debate as to whether episodic memory is unique to humans, or whether it may extend to non-human animals. Although many insightful paradigms have shown elements of episodic memory in numerous species, research has been shrouded with difficulties, stemming from the extensive criteria and the phenomenological nature of such memories. This thesis, therefore, aims to move beyond a debate hindered by definition, and rather than searching for a definite answer to the question, focuses on comparing the similarities and differences between the way humans and animals (specifically, great apes) recall past events.
The thesis beings with an introduction to memory, before focusing on episodic memory and the episodic memory debate. In the following chapter, the subjects (great apes) and the general testing procedure are introduced. In Chapter 3, the distinctiveness effect is investigated in the recall of a past event. The distinctiveness effect refers to the enhanced memory for distinctive, as opposed to non-distinct information. The results suggest that the distinctiveness effect occurs in great apes’ memory of past events, moreover, it occurs regardless of reinforcement, consistent with results found in humans. Chapter 4 explores involuntary memory in great apes; a form of memory that occurs frequently in humans and has been proposed to exist in animals, yet has been largely overlooked. Using a paradigm that draws upon elements of involuntary memory, apes show successful recall of a past event after long delays. Chapter 5 investigates the recall of social information from past events, an area which has received little attention. The results of this chapter indicate that apes fail to integrate social information (who) with what, suggesting that social information may not be readily incorporated into the memory of past events; however, this is likely due to a lack of saliency. The final chapter discusses the findings of the three experimental chapters (3-5), before providing potential avenues for future research.Interocular transfer in the pigeonGraves, Jefferson A.https://hdl.handle.net/10023/145982019-07-15T10:14:22Z1980-01-01T00:00:00ZThe interocular transfer of simultaneously presented visual discriminations was examined in the pigeon (Columba livia) in several experimental situations. When trained monocularly on a jumping stand, there was no evidence of transfer to the other eye-hemisphere system of either pattern or colour discriminations using retraining and reversal learning measures as well as testing. This failure was not due to any obscuring of transfer consequent upon switching the occluder from one eye to the other, nor was there any suggestion of even a small amount of transfer of information from the trained eye to the untrained eye with extensive overtraining and decoupling trials. Binocular training on the jumping stand also revealed that some of the pigeons were learning a discrimination with only one eye in spite of the opportunity to learn with both eyes. When trained in a key pecking task, pigeons demonstrate perfect transfer. Testing revealed that this discrepancy in results is not due to the number of trials given in the two situations, to separation of the stimuli over a greater distance or by a partition, nor to the distance at which the pigeon makes a decision about which stimulus to approach. When the function of the retinal locus of the stimuli was examined, evidence was found in the literature and in my observations that the pigeons were using a different part of the retina when scanning the stimulus display in a key pecking task than on the jumping stand, even though the stimuli in the two situations were located in the same position relative to the bird's head. Specifically, in the key pecking tasks the red area of the retina, which serves the lower binocular portion of the retina, is used. On the jumping stand this area is not used to scan the stimuli. It was then possible to demonstrate a failure of transfer in a key pecking task and successful transfer on the jumping stand by simply manipulating whether the red area was used in scanning the stimuli. The results are discussed in terms of a consequence of binocular convergence from the red area, and when there is a failure of transfer, when the red area is not used, or prevented from being used, the stimuli fall within the monocular field where there is no necessity of later convergence from the two inputs. Active inhibition mechanisms also might serve to lateralize input to one hemisphere.
1980-01-01T00:00:00ZGraves, Jefferson A.The interocular transfer of simultaneously presented visual discriminations was examined in the pigeon (Columba livia) in several experimental situations. When trained monocularly on a jumping stand, there was no evidence of transfer to the other eye-hemisphere system of either pattern or colour discriminations using retraining and reversal learning measures as well as testing. This failure was not due to any obscuring of transfer consequent upon switching the occluder from one eye to the other, nor was there any suggestion of even a small amount of transfer of information from the trained eye to the untrained eye with extensive overtraining and decoupling trials. Binocular training on the jumping stand also revealed that some of the pigeons were learning a discrimination with only one eye in spite of the opportunity to learn with both eyes. When trained in a key pecking task, pigeons demonstrate perfect transfer. Testing revealed that this discrepancy in results is not due to the number of trials given in the two situations, to separation of the stimuli over a greater distance or by a partition, nor to the distance at which the pigeon makes a decision about which stimulus to approach. When the function of the retinal locus of the stimuli was examined, evidence was found in the literature and in my observations that the pigeons were using a different part of the retina when scanning the stimulus display in a key pecking task than on the jumping stand, even though the stimuli in the two situations were located in the same position relative to the bird's head. Specifically, in the key pecking tasks the red area of the retina, which serves the lower binocular portion of the retina, is used. On the jumping stand this area is not used to scan the stimuli. It was then possible to demonstrate a failure of transfer in a key pecking task and successful transfer on the jumping stand by simply manipulating whether the red area was used in scanning the stimuli. The results are discussed in terms of a consequence of binocular convergence from the red area, and when there is a failure of transfer, when the red area is not used, or prevented from being used, the stimuli fall within the monocular field where there is no necessity of later convergence from the two inputs. Active inhibition mechanisms also might serve to lateralize input to one hemisphere.Ocular asymmetries and binocular visionWright, Susan Heatherhttps://hdl.handle.net/10023/145972019-04-01T10:42:09Z1983-01-01T00:00:00ZThis study was undertaken to investigate ocular asymmetries in binocular vision using several dichoptic and binocular viewing paradigms. The literature on eye dominance was reviewed and it revealed that little emphasis both theoretically and experimentally had been placed on binocular viewing situations. The nature of the eye dominance tests and the dichotomous classification of the results suggested that one eye's image was competing against the other. The relationship between the different eye-dominance tests was not clear. A new approach to the study of ocular dominance has been developed in this thesis with specific attention to binocular vision and viewing situations. The term eye dominance has been replaced by the term ocular asymmetries to describe the results and measures derived from these procedures and the nature of the binocular visual approach. The experimental work is divided into three sections. Section one, is concerned with a binocular rivalry procedure using real images and afterimages. Section two, involves a stereoscopic viewing procedure and depth discrimination task with selective attenuation of the stereo-displays. Section three, investigates the interocular transfer of the spatial frequency shift. Measures of ocular asymmetry were derived, from all three procedures and the three sets of scores were positively related. This measure gives both the direction and the degree of the ocular asymmetry. The results indicate that ocular asymmetries are a valid feature of binocular vision. The new measure derived from the depth discrimination experiment provides a quantitative and consistent measure of ocular asymmetry. Special attention has been directed at the involvement of eye movements in all three paradigms and as the underlying factor in the asymmetry results. On the basis of the findings it was suggested that the asymmetry may reside in the binocular system controlling eye movements or reflect an asymmetry in processing speeds of the images from the two eyes arriving at the binocular site. The ocular asymmetry measures do not necessarily indicate eye movements are asymmetrical. It is recommended that ocular asymmetry is a variable to be studied in other investigations of binocular vision and binocular interactions.
1983-01-01T00:00:00ZWright, Susan HeatherThis study was undertaken to investigate ocular asymmetries in binocular vision using several dichoptic and binocular viewing paradigms. The literature on eye dominance was reviewed and it revealed that little emphasis both theoretically and experimentally had been placed on binocular viewing situations. The nature of the eye dominance tests and the dichotomous classification of the results suggested that one eye's image was competing against the other. The relationship between the different eye-dominance tests was not clear. A new approach to the study of ocular dominance has been developed in this thesis with specific attention to binocular vision and viewing situations. The term eye dominance has been replaced by the term ocular asymmetries to describe the results and measures derived from these procedures and the nature of the binocular visual approach. The experimental work is divided into three sections. Section one, is concerned with a binocular rivalry procedure using real images and afterimages. Section two, involves a stereoscopic viewing procedure and depth discrimination task with selective attenuation of the stereo-displays. Section three, investigates the interocular transfer of the spatial frequency shift. Measures of ocular asymmetry were derived, from all three procedures and the three sets of scores were positively related. This measure gives both the direction and the degree of the ocular asymmetry. The results indicate that ocular asymmetries are a valid feature of binocular vision. The new measure derived from the depth discrimination experiment provides a quantitative and consistent measure of ocular asymmetry. Special attention has been directed at the involvement of eye movements in all three paradigms and as the underlying factor in the asymmetry results. On the basis of the findings it was suggested that the asymmetry may reside in the binocular system controlling eye movements or reflect an asymmetry in processing speeds of the images from the two eyes arriving at the binocular site. The ocular asymmetry measures do not necessarily indicate eye movements are asymmetrical. It is recommended that ocular asymmetry is a variable to be studied in other investigations of binocular vision and binocular interactions.The exterior-letter advantage in linear multi-letter arraysDe Bruijn, Oscarhttps://hdl.handle.net/10023/145962019-07-15T10:13:00Z1995-01-01T00:00:00ZWhen linear arrays of unrelated letters (e.g., 'sfdthnc') are presented tachistoscopically centred across a fixation point, letters presented at exterior positions (e.g., 's----c') aregenerally reported more accurately than letters presented in interior positions. This "exterior-letter advantage" suggests that processing is more efficient for exterior letters than for interior letters. Previous researchers have argued that the exterior-letter advantage can be fully accounted for by the influences of lateral interference and mask configuration. However, the processes responsible for the exterior-letter advantage are far from resolved, despite the robustness of the phenomenon and its occurrence in numerous investigations into visual information processing. The experiments reported in this study investigated the role of lateral interference and backward pattern masking in the exterior-letter advantage. To investigate the role of lateral interference, performance was compared across complete 7-letter arrays and arrays in which the presence and proximity of flanking letters was varied by (i) presenting only exterior letters and their immediately flanking interior letter, (ii) varying the number blank letter-spaces by which these letter-pairs were separated, (iii) varying the nature of the characters presented in these displays, and (iv) presenting each exterior/interior letter-pair in isolation. The role of backward pattern masking was investigated (i) using different mask configurations which either matched or exceeded the left and right boundaries of complete letter arrays, and (ii) using masks which overlay only the positions of each exterior/interior letter-pair. The findings indicate that while lateral interference and mask configuration each played a part, neither an imbalance in the number of immediately flanking letters for interior and exterior letters nor mask configuration can entirely account for the exterior-letter advantage.
1995-01-01T00:00:00ZDe Bruijn, OscarWhen linear arrays of unrelated letters (e.g., 'sfdthnc') are presented tachistoscopically centred across a fixation point, letters presented at exterior positions (e.g., 's----c') aregenerally reported more accurately than letters presented in interior positions. This "exterior-letter advantage" suggests that processing is more efficient for exterior letters than for interior letters. Previous researchers have argued that the exterior-letter advantage can be fully accounted for by the influences of lateral interference and mask configuration. However, the processes responsible for the exterior-letter advantage are far from resolved, despite the robustness of the phenomenon and its occurrence in numerous investigations into visual information processing. The experiments reported in this study investigated the role of lateral interference and backward pattern masking in the exterior-letter advantage. To investigate the role of lateral interference, performance was compared across complete 7-letter arrays and arrays in which the presence and proximity of flanking letters was varied by (i) presenting only exterior letters and their immediately flanking interior letter, (ii) varying the number blank letter-spaces by which these letter-pairs were separated, (iii) varying the nature of the characters presented in these displays, and (iv) presenting each exterior/interior letter-pair in isolation. The role of backward pattern masking was investigated (i) using different mask configurations which either matched or exceeded the left and right boundaries of complete letter arrays, and (ii) using masks which overlay only the positions of each exterior/interior letter-pair. The findings indicate that while lateral interference and mask configuration each played a part, neither an imbalance in the number of immediately flanking letters for interior and exterior letters nor mask configuration can entirely account for the exterior-letter advantage.Encoding of relative location of intensity changes in human spatial visionPaterson, Ian R.https://hdl.handle.net/10023/145942019-04-01T10:40:13Z1992-01-01T00:00:00ZThe psychophysical experiments and numerical modelling reported in the present study are an investigation into the encoding of relative location of intensity changes in the human visual system. The study attempted, successfully, to explain some geometric illusions resulting from closely spaced image features ('crowding'), and determined the nature of information necessary for making judgments about the separation of intensity changes for different stimulus configurations. Experiments performed fell into two basic categories; those concerned with spatial interference, and studies of spatial interval judgments. The first set of experiments, studying spatial interference with relative localisation for intensity changes, was based on measurements made with stimuli composed of lowpass filtered bars and edges. The most successful model, which accounted for all of the data, was Watt and Morgan's (1984, 1985) MIRAGE; the results suggest that a good explanation of some geometric illusions can be derived using the principles of low-level vision. Spatial interference is strong evidence for combination of information across spatial scales, and the MIRAGE algorithm makes some highly accurate predictions. Relating the separation of image features is a fundamental task for the visual system, but there is no clear understanding of what information the system has available to perform this task. The second set of experiments explored the perception of separation, and precision of judgments of separation, for bars with a variety of orthoaxial contrast profiles. The data indicate that information is combined across spatial scales (as in MIRAGE) under certain circumstances in making separation judgments; this combination of information across scale occurs when the information on the scales combined is in agreement (ie. all scales have some task-related information), but when variance is added on coarser scales which is not relevant to the task, the system is capable of selecting the finest scales of filters available, and using only the information in the finest scale. This adaptive scale-selection process operates even at very brief exposure durations.
1992-01-01T00:00:00ZPaterson, Ian R.The psychophysical experiments and numerical modelling reported in the present study are an investigation into the encoding of relative location of intensity changes in the human visual system. The study attempted, successfully, to explain some geometric illusions resulting from closely spaced image features ('crowding'), and determined the nature of information necessary for making judgments about the separation of intensity changes for different stimulus configurations. Experiments performed fell into two basic categories; those concerned with spatial interference, and studies of spatial interval judgments. The first set of experiments, studying spatial interference with relative localisation for intensity changes, was based on measurements made with stimuli composed of lowpass filtered bars and edges. The most successful model, which accounted for all of the data, was Watt and Morgan's (1984, 1985) MIRAGE; the results suggest that a good explanation of some geometric illusions can be derived using the principles of low-level vision. Spatial interference is strong evidence for combination of information across spatial scales, and the MIRAGE algorithm makes some highly accurate predictions. Relating the separation of image features is a fundamental task for the visual system, but there is no clear understanding of what information the system has available to perform this task. The second set of experiments explored the perception of separation, and precision of judgments of separation, for bars with a variety of orthoaxial contrast profiles. The data indicate that information is combined across spatial scales (as in MIRAGE) under certain circumstances in making separation judgments; this combination of information across scale occurs when the information on the scales combined is in agreement (ie. all scales have some task-related information), but when variance is added on coarser scales which is not relevant to the task, the system is capable of selecting the finest scales of filters available, and using only the information in the finest scale. This adaptive scale-selection process operates even at very brief exposure durations.Temporal context, object permanence, and spaceBaker, Christopher I.https://hdl.handle.net/10023/145922019-07-15T10:18:08Z1999-01-01T00:00:00ZIn everyday life objects are continually moving into and out of view, yet we experience a stable environment in which objects are "permanent" and have an existence independent of observation. Many non-human species also exhibit such "object permanence", although the nature of their representations of occluded objects remains unclear. This thesis investigated knowledge and representation of occluded objects in Rhesus macaques (Macaca mulatto). At the behavioural level, an analysis of the reaching behaviour of a macaque demonstrated representation for the motivational value of rewards hidden from sight, and provided some evidence for the representation of object form. At the neural level, a population of cells was found in the superior temporal sulcus of macaques that might contribute to object permanence. The cells showed prolonged responses as objects moved gradually out of sight behind occluding screens. This activity was selective for the location of occlusion and did not develop fully until complete occlusion of the object. A small population of bimodal (auditory-visual) cells showed related activity with modulation of response to an auditory stimulus dependent on whether the sound source was in or out of sight. An influence of the position of the stimuli was also observed for these cells. An analysis of cells with diverse response characteristic revealed that positional sensitivity was not limited to a small sub-group of cells within the superior temporal sulcus. This is the first evidence for spatial coding in temporal cortex, a region associated with object recognition. Keywords: object permanence, macaque, STS, multisensory integration, occlusion, spatial coding, dorsal and ventral streams.
1999-01-01T00:00:00ZBaker, Christopher I.In everyday life objects are continually moving into and out of view, yet we experience a stable environment in which objects are "permanent" and have an existence independent of observation. Many non-human species also exhibit such "object permanence", although the nature of their representations of occluded objects remains unclear. This thesis investigated knowledge and representation of occluded objects in Rhesus macaques (Macaca mulatto). At the behavioural level, an analysis of the reaching behaviour of a macaque demonstrated representation for the motivational value of rewards hidden from sight, and provided some evidence for the representation of object form. At the neural level, a population of cells was found in the superior temporal sulcus of macaques that might contribute to object permanence. The cells showed prolonged responses as objects moved gradually out of sight behind occluding screens. This activity was selective for the location of occlusion and did not develop fully until complete occlusion of the object. A small population of bimodal (auditory-visual) cells showed related activity with modulation of response to an auditory stimulus dependent on whether the sound source was in or out of sight. An influence of the position of the stimuli was also observed for these cells. An analysis of cells with diverse response characteristic revealed that positional sensitivity was not limited to a small sub-group of cells within the superior temporal sulcus. This is the first evidence for spatial coding in temporal cortex, a region associated with object recognition. Keywords: object permanence, macaque, STS, multisensory integration, occlusion, spatial coding, dorsal and ventral streams.Perception and recognition of computer-enhanced facial attributes and abstracted prototypesBenson, Philip J.https://hdl.handle.net/10023/145902019-07-15T10:16:30Z1993-01-01T00:00:00ZThe influence of the human facial image was surveyed and the nature of its many interpretations were examined. The role of distinctiveness was considered particularly relevant as it accounted for many of the impressions of character and identity ascribed to individuals. The notion of structural differences with respect to some selective essence of normality is especially important as it allows a wide range of complex facial types to be considered and understood in an objective manner. A software tool was developed which permitted the manipulation of facial images. Quantitative distortions of digital images were examined using perceptual and recognition memory paradigms. Seven experiments investigated the role of distinctiveness in memory for faces using synthesised caricatures. The results showed that caricatures, both photographic and line-drawing, improved recognition speed and accuracy, indicating that both veridical and distinctiveness information are coded for familiar faces in long-term memory. The impact of feature metrics on perceptual estimates of facial age was examined using 'age-caricatured' images and were found to be in relative accordance with the 'intended' computed age. Further modifying the semantics permitted the differences between individual faces to be visualised in terms of facial structure and skin texture patterns. Transformations of identity between two, or more, faces established the necessary matrices which can offer an understanding of facial expression in a categorical manner and the inherent interactions. A procedural extension allowed generation of composite images in which all features are perfectly aligned. Prototypical facial types specified in this manner enabled high-level manipulations to be made of gender and attractiveness; two experiments corroborated previously speculative material and thus gave credence to the prototype model. In summary, psychological assessment of computer-manipulated facial images demonstrated the validity of the objective techniques and highlighted particular parameters which contribute to our perception and recognition of the individual and of underlying facial types.
1993-01-01T00:00:00ZBenson, Philip J.The influence of the human facial image was surveyed and the nature of its many interpretations were examined. The role of distinctiveness was considered particularly relevant as it accounted for many of the impressions of character and identity ascribed to individuals. The notion of structural differences with respect to some selective essence of normality is especially important as it allows a wide range of complex facial types to be considered and understood in an objective manner. A software tool was developed which permitted the manipulation of facial images. Quantitative distortions of digital images were examined using perceptual and recognition memory paradigms. Seven experiments investigated the role of distinctiveness in memory for faces using synthesised caricatures. The results showed that caricatures, both photographic and line-drawing, improved recognition speed and accuracy, indicating that both veridical and distinctiveness information are coded for familiar faces in long-term memory. The impact of feature metrics on perceptual estimates of facial age was examined using 'age-caricatured' images and were found to be in relative accordance with the 'intended' computed age. Further modifying the semantics permitted the differences between individual faces to be visualised in terms of facial structure and skin texture patterns. Transformations of identity between two, or more, faces established the necessary matrices which can offer an understanding of facial expression in a categorical manner and the inherent interactions. A procedural extension allowed generation of composite images in which all features are perfectly aligned. Prototypical facial types specified in this manner enabled high-level manipulations to be made of gender and attractiveness; two experiments corroborated previously speculative material and thus gave credence to the prototype model. In summary, psychological assessment of computer-manipulated facial images demonstrated the validity of the objective techniques and highlighted particular parameters which contribute to our perception and recognition of the individual and of underlying facial types.Digital manipulation of faces and its consequence upon identification and attractivenessLee, Kieran J.https://hdl.handle.net/10023/145872019-04-01T10:41:10Z1999-01-01T00:00:00ZThe thesis investigated perception of facial identity and attractiveness with digital manipulation of facial traits. A presentation time paradigm was developed by which stimuli could be presented for a range of brief display periods. Using this paradigm subjects recognised photo-realistic target faces caricatured in shape with greater accuracy than veridical images consistent with previous findings using reaction time as a measure. Subjects were further required to identify colour representations of famous faces which were either veridical, caricatured in colour space or had enhanced colour saturation and intensity contrast (as contrast controls). Recognition accuracy was greater when viewing the colour-caricatured stimuli than either the veridical images or the contrast controls. The removal of colour to produce grey-scale images also decreased accuracy of face recognition indicating that colour information aids facial identification. Caricaturing of faces, therefore, can be extended to the colour domain and, as with shape caricaturing, enhancement of distinctive information can produce a recognition advantage for famous faces. Subjects were also asked to identify the best-likeness for individuals using photo-realistic stimuli and an interactive paradigm with shape-caricature, colour-caricature and contrast-control varied by the user in real-time. The best-likeness with shape manipulation was a slight anti-caricature while with colour-caricature and contrast-control images a mildly exaggerated image was selected as the best-likeness. Thus although images caricatured substantially in colour or shape (+40%) induce superior recognition compared to veridical images such substantial exaggerations are not seen as best-likenesses under prolonged exposure. The gender typicality for white British and Japanese composite faces was manipulated and subjects presented with the images using both a static forced-choice paradigm and an interactive paradigm. Male and female face shapes with enhanced feminine features were consistently found to be more attractive than average. Preference for enhanced femininity for female faces was greater for subjects making within- than cross-cultural judgements.
1999-01-01T00:00:00ZLee, Kieran J.The thesis investigated perception of facial identity and attractiveness with digital manipulation of facial traits. A presentation time paradigm was developed by which stimuli could be presented for a range of brief display periods. Using this paradigm subjects recognised photo-realistic target faces caricatured in shape with greater accuracy than veridical images consistent with previous findings using reaction time as a measure. Subjects were further required to identify colour representations of famous faces which were either veridical, caricatured in colour space or had enhanced colour saturation and intensity contrast (as contrast controls). Recognition accuracy was greater when viewing the colour-caricatured stimuli than either the veridical images or the contrast controls. The removal of colour to produce grey-scale images also decreased accuracy of face recognition indicating that colour information aids facial identification. Caricaturing of faces, therefore, can be extended to the colour domain and, as with shape caricaturing, enhancement of distinctive information can produce a recognition advantage for famous faces. Subjects were also asked to identify the best-likeness for individuals using photo-realistic stimuli and an interactive paradigm with shape-caricature, colour-caricature and contrast-control varied by the user in real-time. The best-likeness with shape manipulation was a slight anti-caricature while with colour-caricature and contrast-control images a mildly exaggerated image was selected as the best-likeness. Thus although images caricatured substantially in colour or shape (+40%) induce superior recognition compared to veridical images such substantial exaggerations are not seen as best-likenesses under prolonged exposure. The gender typicality for white British and Japanese composite faces was manipulated and subjects presented with the images using both a static forced-choice paradigm and an interactive paradigm. Male and female face shapes with enhanced feminine features were consistently found to be more attractive than average. Preference for enhanced femininity for female faces was greater for subjects making within- than cross-cultural judgements.Computer graphic control over human face and head appearance: to, genetic optimisation of perceptual characteristicsRowland, Duncan Andrewhttps://hdl.handle.net/10023/145852019-04-01T10:41:15Z1998-01-01T00:00:00ZThe aims of this thesis are two-fold. The first is to develop computer graphics that allow quantitative manipulation of complex visual stimuli. The second is to show that such techniques have utility in the domain of perceptual psychology. There are three main sections to this thesis. The first section creates methods for performing transformations of facial appearance along particular perceptual dimensions. This work begins with 2-D image manipulations and then extends the general principles to 3-D. Effectiveness of the techniques is illustrated with plates showing transformation in age, gender and identity. The second section uses Genetic Algorithms to control the appearance of 3-D computer graphics objects and investigates methods of evolving objects that embody various consumer concepts. Computer graphic models of shampoo bottles are successfully evolved to satisfy a selection of aesthetic and perceptual characteristics. The final section returns to facial stimuli and extends the Genetic Algorithm approach to investigate aesthetic preference for 3-D facial surfaces. The study shows that individual human subjects can evolve facial surfaces based upon their own attractiveness preferences. The faces evolved are non-average and there is consistency between subjects about preferred characteristics. The three parts of this thesis have different theoretical backgrounds and literature relevant to each topic is therefore reviewed at the start of each section.
1998-01-01T00:00:00ZRowland, Duncan AndrewThe aims of this thesis are two-fold. The first is to develop computer graphics that allow quantitative manipulation of complex visual stimuli. The second is to show that such techniques have utility in the domain of perceptual psychology. There are three main sections to this thesis. The first section creates methods for performing transformations of facial appearance along particular perceptual dimensions. This work begins with 2-D image manipulations and then extends the general principles to 3-D. Effectiveness of the techniques is illustrated with plates showing transformation in age, gender and identity. The second section uses Genetic Algorithms to control the appearance of 3-D computer graphics objects and investigates methods of evolving objects that embody various consumer concepts. Computer graphic models of shampoo bottles are successfully evolved to satisfy a selection of aesthetic and perceptual characteristics. The final section returns to facial stimuli and extends the Genetic Algorithm approach to investigate aesthetic preference for 3-D facial surfaces. The study shows that individual human subjects can evolve facial surfaces based upon their own attractiveness preferences. The faces evolved are non-average and there is consistency between subjects about preferred characteristics. The three parts of this thesis have different theoretical backgrounds and literature relevant to each topic is therefore reviewed at the start of each section.Visual processing of pictorial and facial images in human and monkeyThomas, Sharon M.https://hdl.handle.net/10023/145832019-04-01T10:41:49Z1992-01-01T00:00:00ZOver the last two decades, the study of 'repetition effects' in behavioural and Event Related Potential (E.R.P) research has originated and added to theories of memory organisation. In this series of experiments, behavioural and E.R.P correlates of human and monkey visual memory were investigated, using the repetition effect as the main index of processing, and manipulating the semantic content of the experimental stimuli. The research has a large founding in established results from lexical studies. The use of pictorial material in this series of experiments extends these results to more general visual memory functions. E.R.P recordings were taken from two monkeys trained extensively to perform a matching-to-sample picture recognition task. The waveforms generated by novel instances of highly familiar pictures were compared to those elicited by repeats. In a further study with unfamiliar pictures the repetition of items had an effect on the evoked potentials for only one of the two subjects. Two further studies were made with one monkey viewing unfamiliar and familiar face pictures. In both these studies, an early potential emerged which was more positive in response to faces than to objects. In order to investigate the importance of the semantic content of stimulus items for memory processes, human E.R.Ps generated by novel and repeated presentations of 'meaningful' and 'meaningless' pictorial images were recorded. Repetition of the meaningful (but not meaningless) pictures attenuated the N400 component associated with the first presentation of a stimulus.
1992-01-01T00:00:00ZThomas, Sharon M.Over the last two decades, the study of 'repetition effects' in behavioural and Event Related Potential (E.R.P) research has originated and added to theories of memory organisation. In this series of experiments, behavioural and E.R.P correlates of human and monkey visual memory were investigated, using the repetition effect as the main index of processing, and manipulating the semantic content of the experimental stimuli. The research has a large founding in established results from lexical studies. The use of pictorial material in this series of experiments extends these results to more general visual memory functions. E.R.P recordings were taken from two monkeys trained extensively to perform a matching-to-sample picture recognition task. The waveforms generated by novel instances of highly familiar pictures were compared to those elicited by repeats. In a further study with unfamiliar pictures the repetition of items had an effect on the evoked potentials for only one of the two subjects. Two further studies were made with one monkey viewing unfamiliar and familiar face pictures. In both these studies, an early potential emerged which was more positive in response to faces than to objects. In order to investigate the importance of the semantic content of stimulus items for memory processes, human E.R.Ps generated by novel and repeated presentations of 'meaningful' and 'meaningless' pictorial images were recorded. Repetition of the meaningful (but not meaningless) pictures attenuated the N400 component associated with the first presentation of a stimulus.The perception of motionBrown, Kenneth Scotthttps://hdl.handle.net/10023/145812019-04-01T10:40:30Z1996-01-01T00:00:00ZExtracting a motion signal for a two-dimensional contour requires the human visual system to derive a velocity vector from the spatially limited receptive fields of motion sensitive cortical cells. An individual cell's response may not specify the contour's true velocity. Models of motion often combine the outputs of different classes of receptive fields to generate a reliable motion signal. Their efficacy was tested by comparing their predictions with human psychophysical performance. The perceived speed of co-linear inclined line segments in horizontal translation was subject to a bias in favour of the local components of the contour. Single tilted lines were also subject to a bias in perceived speed. Experiments investigated the effects of grouping, co-linearity, eccentricity, terminator proximity and stimulus uncertainty on perceived speed and clearly showed that the perceived velocity of line segments is not obtained by a simple averaging process of local velocity signals and veridical velocity signals of line terminators. Variation of the spatial position of terminators was sufficient to abolish the bias in perceived speed of horizontally drifting inclined lines. Neither "vector-average" nor "winner-take-all" rules are sufficient to account for this. The method of integration of one-dimensional components into two-dimensional plaid patterns was explored in two experiments recording thresholds for perceived rotation of drifting plaids. Type II plaids are not subject to the oblique effect found for rotation discrimination thresholds for type IS plaids. Plaid rotation induced by a speed change in one of the components showed that direction perception does not follow a strict interpretation of the "intersection of constraints rule". As current models of motion integration fail to provide a full account of the perceived speed and direction of two-dimensional patterns; higher-order attentional processes should be incorporated into models of motion perception.
1996-01-01T00:00:00ZBrown, Kenneth ScottExtracting a motion signal for a two-dimensional contour requires the human visual system to derive a velocity vector from the spatially limited receptive fields of motion sensitive cortical cells. An individual cell's response may not specify the contour's true velocity. Models of motion often combine the outputs of different classes of receptive fields to generate a reliable motion signal. Their efficacy was tested by comparing their predictions with human psychophysical performance. The perceived speed of co-linear inclined line segments in horizontal translation was subject to a bias in favour of the local components of the contour. Single tilted lines were also subject to a bias in perceived speed. Experiments investigated the effects of grouping, co-linearity, eccentricity, terminator proximity and stimulus uncertainty on perceived speed and clearly showed that the perceived velocity of line segments is not obtained by a simple averaging process of local velocity signals and veridical velocity signals of line terminators. Variation of the spatial position of terminators was sufficient to abolish the bias in perceived speed of horizontally drifting inclined lines. Neither "vector-average" nor "winner-take-all" rules are sufficient to account for this. The method of integration of one-dimensional components into two-dimensional plaid patterns was explored in two experiments recording thresholds for perceived rotation of drifting plaids. Type II plaids are not subject to the oblique effect found for rotation discrimination thresholds for type IS plaids. Plaid rotation induced by a speed change in one of the components showed that direction perception does not follow a strict interpretation of the "intersection of constraints rule". As current models of motion integration fail to provide a full account of the perceived speed and direction of two-dimensional patterns; higher-order attentional processes should be incorporated into models of motion perception.A study of visuomotor behaviour in normal and brain lesioned human subjects, with special reference to line bisection performance in patients with hemispatial neglectHarvey, Monikahttps://hdl.handle.net/10023/145782019-04-01T10:41:28Z1994-01-01T00:00:00ZIn Experiments 1 to 8 an attempt was made to examine the nature of the displacements found in the traditional line bisection test when applied to normal (right-handed), as well as brain lesioned subjects. The problem with this test is that it invariably confounds perceptual and motor components which might both contribute to the observed errors. However, use of the 'landmark task' enables an examination of perceptual effects in isolation. It was found that five out of six neglect patients judged the left half-line of a centrally bisected line as shorter than the right half-line. Moreover, it was consistently shown that cueing strongly influenced judgements in normal and left and right hemisphere lesioned subjects (without neglect) in that it caused them to overestimate the cued part of the line. It was argued that the perception of relative size is subject to systematic distortion as a function of this selective attention within the visual field. Neglect patients may present an abnormal example of this attentionally- induced illusion in that their attentional resources may be abnormally biased towards the ipsilesional space. The result of this imbalance may be to cause, quite directly, a gross abnormality of size perception. Nonetheless one of the neglect patients did not show spatial misperception but spatially misdirected actions, in line with what has been described as directional hypokinesia. Experiments 9 to 12 were designed to demonstrate any possible contribution the right hemisphere might make to visuomotor control, but the data on normal subjects gave little indication of a specific right hemisphere involvement in such tasks. Neither use of a spatial bisection task, nor absence of visual feedback of the moving hand or arm seemed to produce left hand advantages on the dependent measures. On the other hand, RCVA patients proved to be impaired in their reaching behaviour in that they erred systematically to the right of the true target over all three spatial positions, in the absence of visual feedback. The bias was interpreted as a pure example of directional hypokinesia.
1994-01-01T00:00:00ZHarvey, MonikaIn Experiments 1 to 8 an attempt was made to examine the nature of the displacements found in the traditional line bisection test when applied to normal (right-handed), as well as brain lesioned subjects. The problem with this test is that it invariably confounds perceptual and motor components which might both contribute to the observed errors. However, use of the 'landmark task' enables an examination of perceptual effects in isolation. It was found that five out of six neglect patients judged the left half-line of a centrally bisected line as shorter than the right half-line. Moreover, it was consistently shown that cueing strongly influenced judgements in normal and left and right hemisphere lesioned subjects (without neglect) in that it caused them to overestimate the cued part of the line. It was argued that the perception of relative size is subject to systematic distortion as a function of this selective attention within the visual field. Neglect patients may present an abnormal example of this attentionally- induced illusion in that their attentional resources may be abnormally biased towards the ipsilesional space. The result of this imbalance may be to cause, quite directly, a gross abnormality of size perception. Nonetheless one of the neglect patients did not show spatial misperception but spatially misdirected actions, in line with what has been described as directional hypokinesia. Experiments 9 to 12 were designed to demonstrate any possible contribution the right hemisphere might make to visuomotor control, but the data on normal subjects gave little indication of a specific right hemisphere involvement in such tasks. Neither use of a spatial bisection task, nor absence of visual feedback of the moving hand or arm seemed to produce left hand advantages on the dependent measures. On the other hand, RCVA patients proved to be impaired in their reaching behaviour in that they erred systematically to the right of the true target over all three spatial positions, in the absence of visual feedback. The bias was interpreted as a pure example of directional hypokinesia.Visual processing in a primate temporal association cortex: insensitivity to self-induced motionHietanen, Jari K.https://hdl.handle.net/10023/145762019-04-01T10:41:42Z1993-01-01T00:00:00ZAn animal's own behaviour can give rise to sensory stimulation that is very similar to stimulation of completely external origin. Much of this self-induced stimulation has little informative value to the animal and may even interfere with the processing of externally-induced stimulation. A high-level association area in the temporal cortex of macaque (superior temporal polysensory area, STP) which has been shown to participate in the analysis of visual motion was targeted in a series of experiments in order to investigate whether this brain area discriminates externally- and self-induced stimulation in its visual motion processing. Earlier results in somatosensory processing within this same brain area provided grounds for this presumption The cells studied in here were sensitive to the presence of motion but showed no selectivity for the form of the stimulus. 25% of all visually responsive cells in area STP were classified as belonging to this class of cells. This group of cells was further categorized into unidirectional (39%), bidirectional (4%) and pandirectional (57%) cells. Tuning to direction varied in sharpness. For most cells the angular change in direction required to reduce response to half maximal was between 45 and 70 degrees. The optimal directions of cells appeared clustered around cartesian axes, (up/down, left/right and towards/away). The response latency varied between 35.0-126.4 ms (mean 90.9 ms). On average cell responses showed a transient burst of activity followed by a tonic discharge maintained for the duration of stimulation. 83% of the motion sensitive cells lacking form selectivity responded to any stimuli moved by the experimenter, but gave no response to the sight of the animal's own limb movements. The cells remained, however, responsive to external stimulation while the monkey's own hand was moving in view. Responses to self-induced movements were recovered if the monkey introduced a novel object in its hand into view. That the response discrimination between externally- and self-induced stimulation was not caused by differences in the visual appearance of the stimuli was confirmed in the second experiment where the monkey was trained to rotate a handle connected to a patterned cylinder in order to generate visual motion stimulation over a fixation point. 61% of the tested cells discriminated between pattern motion generated by the monkey and by the experimenter. It was shown that the monkey's motor activity as such (turning a handle without visible cylinder rotation) did not affect the cells' spontaneous activity. Some indication was received to suggest that the discriminative mechanism is using not only (motor) corollary discharges but also proprioceptive input. These results also gave evidence of the plasticity of discriminative processing in STP for the animal's life-time experiences. Finally, the cells were studied for their responsiveness for image motion resulting from movements of external objects and movements of the animal's body (self-motion). 84% of the cells responded only to visual object-motion and failed to respond to visual motion resulting from animal's self-motion. The experiments also revealed that area STP processes visual motion mostly in observer- relative terms, i.e. in reference to the perceiver itself. The results provide one explanation for the functional significance of the convergence of several modalities of sensory (and motor) input in the STP. It is suggested that area STP works as a "neural filter" to separate expected sensory consequences resulting from one's own actions from those that originate from the actions of other animals or environmental events.
1993-01-01T00:00:00ZHietanen, Jari K.An animal's own behaviour can give rise to sensory stimulation that is very similar to stimulation of completely external origin. Much of this self-induced stimulation has little informative value to the animal and may even interfere with the processing of externally-induced stimulation. A high-level association area in the temporal cortex of macaque (superior temporal polysensory area, STP) which has been shown to participate in the analysis of visual motion was targeted in a series of experiments in order to investigate whether this brain area discriminates externally- and self-induced stimulation in its visual motion processing. Earlier results in somatosensory processing within this same brain area provided grounds for this presumption The cells studied in here were sensitive to the presence of motion but showed no selectivity for the form of the stimulus. 25% of all visually responsive cells in area STP were classified as belonging to this class of cells. This group of cells was further categorized into unidirectional (39%), bidirectional (4%) and pandirectional (57%) cells. Tuning to direction varied in sharpness. For most cells the angular change in direction required to reduce response to half maximal was between 45 and 70 degrees. The optimal directions of cells appeared clustered around cartesian axes, (up/down, left/right and towards/away). The response latency varied between 35.0-126.4 ms (mean 90.9 ms). On average cell responses showed a transient burst of activity followed by a tonic discharge maintained for the duration of stimulation. 83% of the motion sensitive cells lacking form selectivity responded to any stimuli moved by the experimenter, but gave no response to the sight of the animal's own limb movements. The cells remained, however, responsive to external stimulation while the monkey's own hand was moving in view. Responses to self-induced movements were recovered if the monkey introduced a novel object in its hand into view. That the response discrimination between externally- and self-induced stimulation was not caused by differences in the visual appearance of the stimuli was confirmed in the second experiment where the monkey was trained to rotate a handle connected to a patterned cylinder in order to generate visual motion stimulation over a fixation point. 61% of the tested cells discriminated between pattern motion generated by the monkey and by the experimenter. It was shown that the monkey's motor activity as such (turning a handle without visible cylinder rotation) did not affect the cells' spontaneous activity. Some indication was received to suggest that the discriminative mechanism is using not only (motor) corollary discharges but also proprioceptive input. These results also gave evidence of the plasticity of discriminative processing in STP for the animal's life-time experiences. Finally, the cells were studied for their responsiveness for image motion resulting from movements of external objects and movements of the animal's body (self-motion). 84% of the cells responded only to visual object-motion and failed to respond to visual motion resulting from animal's self-motion. The experiments also revealed that area STP processes visual motion mostly in observer- relative terms, i.e. in reference to the perceiver itself. The results provide one explanation for the functional significance of the convergence of several modalities of sensory (and motor) input in the STP. It is suggested that area STP works as a "neural filter" to separate expected sensory consequences resulting from one's own actions from those that originate from the actions of other animals or environmental events.Cerebral hemispheric studies on the visual perception of motionMackenzie, Alexanderhttps://hdl.handle.net/10023/145742019-04-01T10:42:15Z1981-01-01T00:00:00ZExperiments were conducted to examine the differential capabilities of the cerebral hemispheres for the visual perception of motion. Subjects were normal right handed adult male and female humans. Stimuli were viewed binocularly and responses were manual in all studies. Lateralized low contrast real motion was presented using random texture patterns. The task was to correctly detect the direction of motion. The outcome was a significant hemisphere x trials interaction. The right hemisphere improved significantly over trials while the left hemisphere did not. Using random texture patterns in which a small lateralized square was presented in apparent motion, hemispheric superiorities were found to depend on fairly basic stimulus parameters. For low contrast relatively long stimulus field durations, the right hemisphere was significantly superior. For higher contrast apparent motion stimuli with a "masking" ISI, the left hemisphere was significantly better at accurately detecting the direction of motion. V shaped stimuli may be presented in apparent motion so as to be seen as either moving within the stimulus plane, or rotating in depth outside it. The percentage of "space" (i.e., rotation) responses increases as the ISI is lengthened. The hemispheres did not differ significantly in their judgments of motion in depth, therefore, they appear to be employing identically calibrated detection mechanisms. However, female right hemisphere "space" responses remained constant over trials, while analogous male responses decreased linearly. Stimulus parameters which had been shown in earlier experiments to result in hemispheric differences were avoided, and subjects required to identify apparently moving shapes in a random texture background. No hemispheric differences were observed in this detection task. An additional finding was that female subjects tend to more frequently report that sub-vocal verbalization mediated their (manual) responses.
1981-01-01T00:00:00ZMackenzie, AlexanderExperiments were conducted to examine the differential capabilities of the cerebral hemispheres for the visual perception of motion. Subjects were normal right handed adult male and female humans. Stimuli were viewed binocularly and responses were manual in all studies. Lateralized low contrast real motion was presented using random texture patterns. The task was to correctly detect the direction of motion. The outcome was a significant hemisphere x trials interaction. The right hemisphere improved significantly over trials while the left hemisphere did not. Using random texture patterns in which a small lateralized square was presented in apparent motion, hemispheric superiorities were found to depend on fairly basic stimulus parameters. For low contrast relatively long stimulus field durations, the right hemisphere was significantly superior. For higher contrast apparent motion stimuli with a "masking" ISI, the left hemisphere was significantly better at accurately detecting the direction of motion. V shaped stimuli may be presented in apparent motion so as to be seen as either moving within the stimulus plane, or rotating in depth outside it. The percentage of "space" (i.e., rotation) responses increases as the ISI is lengthened. The hemispheres did not differ significantly in their judgments of motion in depth, therefore, they appear to be employing identically calibrated detection mechanisms. However, female right hemisphere "space" responses remained constant over trials, while analogous male responses decreased linearly. Stimulus parameters which had been shown in earlier experiments to result in hemispheric differences were avoided, and subjects required to identify apparently moving shapes in a random texture background. No hemispheric differences were observed in this detection task. An additional finding was that female subjects tend to more frequently report that sub-vocal verbalization mediated their (manual) responses.Poor readers' use of orthographic information in reading, memory and phonological tasksMcNeil, Alan M.https://hdl.handle.net/10023/144712019-04-01T10:40:32Z2002-01-01T00:00:00ZThis thesis examined the abilities of 10-12 year old poor readers and reading age controls in phonological processing, printed word learning, reading and memory based tasks. It was found that the poor readers showed little impairment in carrying out phonological segmentation of spoken words, though there was more marked impairment with nonwords. Nonword reading was found to be slower than that of controls and poor readers also demonstrated a tendency to provide letter names rather than sounds in a phoneme identification task. In a study of learning new print vocabulary it was found that the poor readers were slower than controls to learn to read the set of nonwords accurately, and had poorer auditory memory for the items. However, they were much better at identifying these items in a visual recognition task. They also showed a less marked regularity effect and were more influenced by the visual appearance of words in an auditory rhyme judgement task. In a study of their working memories, the poor readers showed a visual bias in their memory codes for serial recall of pictorial stimuli, i.e. they showed no word length effect, a phonemic similarity effect of reduced magnitude, and a visual similarity effect. This indicated the use of a visual strategy to remember pictures, rather than the verbal coding preferred by the controls. When words were presented auditorily or in print form, however, the poor readers showed normal phonemic similarity and word length effects. It was concluded that poor readers rely on visual information where the presented images are highly codable, and verbal recoding is not obligatory, but that they will make use of phonological coding when the stimuli are not easily codable visually in memory. The results of these investigations suggest that these poor readers' visual and verbal coding systems might be poorly linked. Thus, when learning to read new words poor readers might prefer to use visual coding. Accordingly, poor readers may rely on intact visual processes because they need to compensate for inefficient or poorly connected visual and verbal systems, rather than because they have inefficient phonological processing skills as such.
2002-01-01T00:00:00ZMcNeil, Alan M.This thesis examined the abilities of 10-12 year old poor readers and reading age controls in phonological processing, printed word learning, reading and memory based tasks. It was found that the poor readers showed little impairment in carrying out phonological segmentation of spoken words, though there was more marked impairment with nonwords. Nonword reading was found to be slower than that of controls and poor readers also demonstrated a tendency to provide letter names rather than sounds in a phoneme identification task. In a study of learning new print vocabulary it was found that the poor readers were slower than controls to learn to read the set of nonwords accurately, and had poorer auditory memory for the items. However, they were much better at identifying these items in a visual recognition task. They also showed a less marked regularity effect and were more influenced by the visual appearance of words in an auditory rhyme judgement task. In a study of their working memories, the poor readers showed a visual bias in their memory codes for serial recall of pictorial stimuli, i.e. they showed no word length effect, a phonemic similarity effect of reduced magnitude, and a visual similarity effect. This indicated the use of a visual strategy to remember pictures, rather than the verbal coding preferred by the controls. When words were presented auditorily or in print form, however, the poor readers showed normal phonemic similarity and word length effects. It was concluded that poor readers rely on visual information where the presented images are highly codable, and verbal recoding is not obligatory, but that they will make use of phonological coding when the stimuli are not easily codable visually in memory. The results of these investigations suggest that these poor readers' visual and verbal coding systems might be poorly linked. Thus, when learning to read new words poor readers might prefer to use visual coding. Accordingly, poor readers may rely on intact visual processes because they need to compensate for inefficient or poorly connected visual and verbal systems, rather than because they have inefficient phonological processing skills as such.Social and environmental influences of smoking behaviour among female nurses and teachers in Scotland : the role of social capitalDutchak, Jacqueline J.https://hdl.handle.net/10023/143352023-10-24T08:15:30Z2002-01-01T00:00:00ZCigarette smoking is one of the most important causes of morbidity and premature mortality in developed countries. Since almost one-third of women in Scotland smoke, the health implications are paramount. Smoking rates among female professionals have decreased in recent years in the UK but they have not fallen equally for all occupations within this group. Historically, female nurses have had higher rates of smoking than other women in the general population while female teachers have had much lower rates. Recent work has revealed that smoking prevalence among nurses has declined in the UK and has reached levels similar to or lower than that of other women. The aims of this thesis are to gain a recent estimate of smoking prevalence among female nurses and teachers in Scotland, to find out why some of these women smoke, why others never started, and why others stopped. This endeavour considers their work and home environments, their interactions with colleagues within and outside the workplace, and their levels of trust, networks, and co-operation in the workplace and neighbourhood. In addition to their current circumstances, this thesis also examines retrospective social capital and deprivation. This study revealed that 31% of nurses and 7% of teachers were smokers, with prevalence of the former much higher than that of other women in the same social class and the latter prevalence much lower. The significant predictors, following multivariate analysis, of smoking and its cessation are varied and include individual, social, economic, and environmental factors. Of particular interest to this study is iv that each of the constructs of social capital have significant and independent effects on smoking and its cessation but that the relationship is neither entirely positive nor completely linear. Furthermore, smoking is often used by women in order to create space and time for oneself in order to break from reality. It is also used to by many women as a means of exerting control over their life. Policies to prevent smoking or aid in its cessation must therefore recognise the important roles of social, economic, environmental and biological influences and how these vary during the lifecourse.
2002-01-01T00:00:00ZDutchak, Jacqueline J.Cigarette smoking is one of the most important causes of morbidity and premature mortality in developed countries. Since almost one-third of women in Scotland smoke, the health implications are paramount. Smoking rates among female professionals have decreased in recent years in the UK but they have not fallen equally for all occupations within this group. Historically, female nurses have had higher rates of smoking than other women in the general population while female teachers have had much lower rates. Recent work has revealed that smoking prevalence among nurses has declined in the UK and has reached levels similar to or lower than that of other women. The aims of this thesis are to gain a recent estimate of smoking prevalence among female nurses and teachers in Scotland, to find out why some of these women smoke, why others never started, and why others stopped. This endeavour considers their work and home environments, their interactions with colleagues within and outside the workplace, and their levels of trust, networks, and co-operation in the workplace and neighbourhood. In addition to their current circumstances, this thesis also examines retrospective social capital and deprivation. This study revealed that 31% of nurses and 7% of teachers were smokers, with prevalence of the former much higher than that of other women in the same social class and the latter prevalence much lower. The significant predictors, following multivariate analysis, of smoking and its cessation are varied and include individual, social, economic, and environmental factors. Of particular interest to this study is iv that each of the constructs of social capital have significant and independent effects on smoking and its cessation but that the relationship is neither entirely positive nor completely linear. Furthermore, smoking is often used by women in order to create space and time for oneself in order to break from reality. It is also used to by many women as a means of exerting control over their life. Policies to prevent smoking or aid in its cessation must therefore recognise the important roles of social, economic, environmental and biological influences and how these vary during the lifecourse.Cognitive representation of challenging behaviour among staff working with adults with learning disabilities : an evaluation of the impact of an open learning training courseCampbell, Martinhttps://hdl.handle.net/10023/143332019-04-01T10:42:00Z2004-01-01T00:00:00ZThis was an investigation into the relationship between quality of care and staff views of, and responses to, challenging behaviour in adults with learning disabilities. Cognitive representations have been identified as a determinant of therapeutic outcomes in a variety of health care settings. There were two main aims of this study. First, to describe and measure the cognitive representations of challenging behaviour among staff working with adults with learning disabilities and second, to evaluate the effects of training on these views held by staff. Existing literature was reviewed. A Likert type questionnaire, the Challenging Behaviour Representation Questionnaire (CBRQ) was developed to record staff views. The CBRQ draws on two existing measures: the Illness Perception Questionnaire (IPQ) and the Challenging Behaviour Attributions Scale (CHABA). The CBRQ will give a new method of evaluating the staff views most often associated with evidence-based practice, helping behaviours and positive outcomes. Questionnaire items were generated from responses by 300 staff, to assess the applicability of Leventhal's Self Regulatory model in the context of challenging behaviour. The rating scales in the questionnaire were theoretically derived, based on the dimensions of Leventhal's model (identity, cause, consequences, treatment/control, time-line). An 'emotional-reaction' dimension was added, suggested by more recent research. The use of the Leventhal model was supported, with the exception of the 'time line' component. The questionnaire was tested for reliability and validity then administered before and after training to staff in three different groups. Targeted training changed cognitive representation of challenging behaviour overall, as measured by the CBRQ, and this change was statistically significantly in two of the five dimensions for the experimental group. Other results suggest that dimensions of cognitive representation are affected in different and complex ways by training. The statistical and the practical significance of the results are discussed in relation to staff training and therapeutic outcomes for people with learning disabilities. A 'staff-regulatory' model of cognitive representation is proposed linking cognitive representation and challenging behaviour.
2004-01-01T00:00:00ZCampbell, MartinThis was an investigation into the relationship between quality of care and staff views of, and responses to, challenging behaviour in adults with learning disabilities. Cognitive representations have been identified as a determinant of therapeutic outcomes in a variety of health care settings. There were two main aims of this study. First, to describe and measure the cognitive representations of challenging behaviour among staff working with adults with learning disabilities and second, to evaluate the effects of training on these views held by staff. Existing literature was reviewed. A Likert type questionnaire, the Challenging Behaviour Representation Questionnaire (CBRQ) was developed to record staff views. The CBRQ draws on two existing measures: the Illness Perception Questionnaire (IPQ) and the Challenging Behaviour Attributions Scale (CHABA). The CBRQ will give a new method of evaluating the staff views most often associated with evidence-based practice, helping behaviours and positive outcomes. Questionnaire items were generated from responses by 300 staff, to assess the applicability of Leventhal's Self Regulatory model in the context of challenging behaviour. The rating scales in the questionnaire were theoretically derived, based on the dimensions of Leventhal's model (identity, cause, consequences, treatment/control, time-line). An 'emotional-reaction' dimension was added, suggested by more recent research. The use of the Leventhal model was supported, with the exception of the 'time line' component. The questionnaire was tested for reliability and validity then administered before and after training to staff in three different groups. Targeted training changed cognitive representation of challenging behaviour overall, as measured by the CBRQ, and this change was statistically significantly in two of the five dimensions for the experimental group. Other results suggest that dimensions of cognitive representation are affected in different and complex ways by training. The statistical and the practical significance of the results are discussed in relation to staff training and therapeutic outcomes for people with learning disabilities. A 'staff-regulatory' model of cognitive representation is proposed linking cognitive representation and challenging behaviour.Masculinity and sexual coercion : a paradoxical relationshipMuir, Granthttps://hdl.handle.net/10023/142602019-04-01T10:41:20Z2003-01-01T00:00:00ZPrevious work on masculinity and sexual coercion has proposed either that sexual coercion is an expression of a traditional ideology of masculinity, or that sexual coercion is a resource in the construction of masculinity. That is, they have proposed that masculinity is either cognitive or strategic. It is proposed, in this thesis, that these viewpoints should be integrated and that masculinity should be thought of as both cognitive and strategic. Using the SIDE (Social Identity Definition and Enactment) model as a framework, there would, in relation to masculinity and sexual coercion, seem to be a paradox. That is, on the one hand, traditional masculinity is associated with the inclination to be sexually coercive, that there is a traditional ideology of masculinity which people internalise and which influences their behaviour. However, on the other hand, the actual expression of sexual coercion undermines masculinity. That is, men who engage in sexual coercion are perceived, by other men, as abusing their power and as less masculine, as not real men. Five studies are presented which support this notion of a paradox. However, this paradox is slightly different to that originally proposed. Rather than it being the case that men who most endorse traditional masculinity being those who most endorse coercion against women, it is those who we describe as being 'insecure' in their traditional masculinity who are most inclined to be coercive. A further two studies are presented which working from a basic assumption of this thesis, that the relationship between men and women is a relationship of unequal power consider, firstly, when the paradox might arise and shows that a challenge by a woman is perceived as a threat to masculinity. Secondly, in addressing how men might resolve the paradox, the final study considers the contexts in which coercion might be enacted and shows that when a challenge engenders feelings of threat to masculinity, this may translated into the enactment of sexual coercion, but only in a private context. The implications of this research and possible future directions are discussed.
2003-01-01T00:00:00ZMuir, GrantPrevious work on masculinity and sexual coercion has proposed either that sexual coercion is an expression of a traditional ideology of masculinity, or that sexual coercion is a resource in the construction of masculinity. That is, they have proposed that masculinity is either cognitive or strategic. It is proposed, in this thesis, that these viewpoints should be integrated and that masculinity should be thought of as both cognitive and strategic. Using the SIDE (Social Identity Definition and Enactment) model as a framework, there would, in relation to masculinity and sexual coercion, seem to be a paradox. That is, on the one hand, traditional masculinity is associated with the inclination to be sexually coercive, that there is a traditional ideology of masculinity which people internalise and which influences their behaviour. However, on the other hand, the actual expression of sexual coercion undermines masculinity. That is, men who engage in sexual coercion are perceived, by other men, as abusing their power and as less masculine, as not real men. Five studies are presented which support this notion of a paradox. However, this paradox is slightly different to that originally proposed. Rather than it being the case that men who most endorse traditional masculinity being those who most endorse coercion against women, it is those who we describe as being 'insecure' in their traditional masculinity who are most inclined to be coercive. A further two studies are presented which working from a basic assumption of this thesis, that the relationship between men and women is a relationship of unequal power consider, firstly, when the paradox might arise and shows that a challenge by a woman is perceived as a threat to masculinity. Secondly, in addressing how men might resolve the paradox, the final study considers the contexts in which coercion might be enacted and shows that when a challenge engenders feelings of threat to masculinity, this may translated into the enactment of sexual coercion, but only in a private context. The implications of this research and possible future directions are discussed.Vocal attractivenessFeinberg, David R.https://hdl.handle.net/10023/142532019-04-01T10:41:00Z2005-01-01T00:00:00ZIn this thesis, I aimed to explore vocal attractiveness from an evolutionary perspective: how listener's preferences for vocal qualities of potential partners could increase mating success and reproductive success. Chapters 1-4 outline the background to the thesis, reviews acoustics, sexual selection theory, and human mate-choice. In chapter 5, I correlated attributions made to voices to the acoustic properties of the voices. In men's voices, pitch negatively predicted vocal attractiveness. Attributions of masculinity, size, age, health and vocal attractiveness were all positively correlated. In women's voices, pitch, formant dispersion and perceived health positively predicted vocal attractiveness. Masculinity, size and age negatively predicted vocal attractiveness. In chapter 6, I measured the effect of manipulating fundamental and/or formant frequencies (apparent vocal-tract length) on vocal attributions. Women found men's voices with lowered voice pitch and decreased formant dispersion more attractive, masculine, large, older and healthier. Women's size predicted preference for male vocal- tract length. In chapter 7, I explored attitudes to voices speaking vowels and whole sentences using a correlation design and acoustic manipulations. Women's self-rated attractiveness positively predicted vocal masculinity preferences. Most of the remaining studies focus on how hormones relate to vocal production and perception. Women with less oestrogen showed the biggest menstrual cycle shifts in vocal masculinity preferences, preferring masculinity most in the fertile phase (chapter 8). Men's testosterone levels predicted the size of changes in attributions of dominance to men's voices (chapter 9). Women's voice pitch correlated with facial-metric masculinity and facial attractiveness (chapter 10). Men preferred women's voices with raised pitch to lowered pitch at multiple levels of starting pitch (chapter 11). These findings indicate men preferred femininity to averageness. In chapter 12, I relate the work in this thesis to other work and the broader evolutionary perspective.
2005-01-01T00:00:00ZFeinberg, David R.In this thesis, I aimed to explore vocal attractiveness from an evolutionary perspective: how listener's preferences for vocal qualities of potential partners could increase mating success and reproductive success. Chapters 1-4 outline the background to the thesis, reviews acoustics, sexual selection theory, and human mate-choice. In chapter 5, I correlated attributions made to voices to the acoustic properties of the voices. In men's voices, pitch negatively predicted vocal attractiveness. Attributions of masculinity, size, age, health and vocal attractiveness were all positively correlated. In women's voices, pitch, formant dispersion and perceived health positively predicted vocal attractiveness. Masculinity, size and age negatively predicted vocal attractiveness. In chapter 6, I measured the effect of manipulating fundamental and/or formant frequencies (apparent vocal-tract length) on vocal attributions. Women found men's voices with lowered voice pitch and decreased formant dispersion more attractive, masculine, large, older and healthier. Women's size predicted preference for male vocal- tract length. In chapter 7, I explored attitudes to voices speaking vowels and whole sentences using a correlation design and acoustic manipulations. Women's self-rated attractiveness positively predicted vocal masculinity preferences. Most of the remaining studies focus on how hormones relate to vocal production and perception. Women with less oestrogen showed the biggest menstrual cycle shifts in vocal masculinity preferences, preferring masculinity most in the fertile phase (chapter 8). Men's testosterone levels predicted the size of changes in attributions of dominance to men's voices (chapter 9). Women's voice pitch correlated with facial-metric masculinity and facial attractiveness (chapter 10). Men preferred women's voices with raised pitch to lowered pitch at multiple levels of starting pitch (chapter 11). These findings indicate men preferred femininity to averageness. In chapter 12, I relate the work in this thesis to other work and the broader evolutionary perspective.Father absence, attraction and developmentBoothroyd, Lyndahttps://hdl.handle.net/10023/141992019-04-01T10:40:26Z2004-01-01T00:00:00ZSince Draper & Harpending (1982) proposed that father absence would be associated with a shift in reproductive strategy, a body of literature has accumulated supporting their claims. This thesis explores further aspects of father absence theory, utilising computergraphic facial processing. It opens with an overview of both father absence theory (Chapter 1) and the Evolutionary Psychology of attraction (Chapter 2). Part 1 Part 1 explores the meaning of masculinity in partner choice scenarios. Male facial masculinity co-varied with facial age but not apparent facial health both in tenns of women's preferences (Study 1) and women's direct perceptions (Study 2). This suggested that masculinity in male faces is not a cue to immunocompetence health status as other authors have suggested, In Study 3, while masculine faces were perceived as more dominant than feminised faces, they were otherwise considered poorer quality partners. It was suggested that masculinity was attractive because of a 'sexy son' mechanism (dominance increasing offspring reproductive success), which was traded off against the anti-social traits associated with masculinity. Part 2 Studies 4, 5 and 6 found that father absence or poor relationships with the parents generally reduced masculinity preference and age preference (although in Study 5, this effect was moderated by relationship status). This contradicted predictions made from traditional father absence literature (that father absence should be associated with a short term strategy and therefore masculinity preference). Sociological explanations were discounted as family background did not relate to the traits women said they desired in a partner (Study 7). Altogether these results raised questions about the attractiveness and self-esteem of father absent females. Part 3 therefore investigated the physical development of these females. Part 3 Study 8 found that marital difficulties between parents were associated with an increase in perceived facial masculinity in both male and female offspring's faces, a decrease in facial attractiveness and increased weight and waist-hip ratio in women. Study 9 found that levels of progesterone were inversely related to quality of parental relationship. The overarching conclusions of the thesis were that there appears to be an effect' of physical masculinisation which is associated with father absence. This masculinisation may be the predicator for previously observed father absence effects, and the results in Part 2. As such, attachment based explanations of father absence effects (such as Belsky et al, 1991) may be redundant.
2004-01-01T00:00:00ZBoothroyd, LyndaSince Draper & Harpending (1982) proposed that father absence would be associated with a shift in reproductive strategy, a body of literature has accumulated supporting their claims. This thesis explores further aspects of father absence theory, utilising computergraphic facial processing. It opens with an overview of both father absence theory (Chapter 1) and the Evolutionary Psychology of attraction (Chapter 2). Part 1 Part 1 explores the meaning of masculinity in partner choice scenarios. Male facial masculinity co-varied with facial age but not apparent facial health both in tenns of women's preferences (Study 1) and women's direct perceptions (Study 2). This suggested that masculinity in male faces is not a cue to immunocompetence health status as other authors have suggested, In Study 3, while masculine faces were perceived as more dominant than feminised faces, they were otherwise considered poorer quality partners. It was suggested that masculinity was attractive because of a 'sexy son' mechanism (dominance increasing offspring reproductive success), which was traded off against the anti-social traits associated with masculinity. Part 2 Studies 4, 5 and 6 found that father absence or poor relationships with the parents generally reduced masculinity preference and age preference (although in Study 5, this effect was moderated by relationship status). This contradicted predictions made from traditional father absence literature (that father absence should be associated with a short term strategy and therefore masculinity preference). Sociological explanations were discounted as family background did not relate to the traits women said they desired in a partner (Study 7). Altogether these results raised questions about the attractiveness and self-esteem of father absent females. Part 3 therefore investigated the physical development of these females. Part 3 Study 8 found that marital difficulties between parents were associated with an increase in perceived facial masculinity in both male and female offspring's faces, a decrease in facial attractiveness and increased weight and waist-hip ratio in women. Study 9 found that levels of progesterone were inversely related to quality of parental relationship. The overarching conclusions of the thesis were that there appears to be an effect' of physical masculinisation which is associated with father absence. This masculinisation may be the predicator for previously observed father absence effects, and the results in Part 2. As such, attachment based explanations of father absence effects (such as Belsky et al, 1991) may be redundant.Scots' attitudes to Britain and to the European Union : the psychology of national segregation and supra-national integrationSindic, Denishttps://hdl.handle.net/10023/141962019-04-01T10:41:34Z2005-01-01T00:00:00ZThis thesis is concerned with attitudes towards supra-national bodies, and more specifically with Scots' attitudes towards union in Britain and Europe. Firstly, it is suggested that support for, or opposition, to integration in a supra-national body depends on the extent to which this body is believed to enhance or undermine the ability to express national identity {identity enhancement vs. identity undermining). Identity undermining, in turn, depends upon a combined sense of incompatibility with outgroup identities/interests and of ingroup powerlessness within the supranational body. Secondly, it is suggested that these features of the social context and of identity meanings can be actively constructed in order to fulfil strategic purposes, such as persuading audiences in favour of separatism or integration. Five studies are reported which investigated these hypotheses. In study 1, we looked at the discourses of Scottish politicians and at the way their accounts of group identities and social reality could be understood in strategic terms, i.e. in relation to their political projects regarding Scotland's status in Britain and in Europe. In the second study, a survey design was used in order to provide quantitative evidence of the relationship between identity undermining, incompatibility, powerlessness and separatism. The third (experimental) study sought to clarify the causal relationship between these variables and showed that manipulating identity undermining lead to increased support for separatism. Finally, the fourth and the fifth (experimental) studies suggested that identity constructions, in the form of judgements of group prototypicality, can vary as a function of the strategic claim made by participants. In conclusion, the merits are stressed of an approach to identity processes and attitudes towards supra-national bodies that is sensitive to both context and content. It is also stressed that context and contents should not be taken as perceptual givens but as actively constructed by social actors.
2005-01-01T00:00:00ZSindic, DenisThis thesis is concerned with attitudes towards supra-national bodies, and more specifically with Scots' attitudes towards union in Britain and Europe. Firstly, it is suggested that support for, or opposition, to integration in a supra-national body depends on the extent to which this body is believed to enhance or undermine the ability to express national identity {identity enhancement vs. identity undermining). Identity undermining, in turn, depends upon a combined sense of incompatibility with outgroup identities/interests and of ingroup powerlessness within the supranational body. Secondly, it is suggested that these features of the social context and of identity meanings can be actively constructed in order to fulfil strategic purposes, such as persuading audiences in favour of separatism or integration. Five studies are reported which investigated these hypotheses. In study 1, we looked at the discourses of Scottish politicians and at the way their accounts of group identities and social reality could be understood in strategic terms, i.e. in relation to their political projects regarding Scotland's status in Britain and in Europe. In the second study, a survey design was used in order to provide quantitative evidence of the relationship between identity undermining, incompatibility, powerlessness and separatism. The third (experimental) study sought to clarify the causal relationship between these variables and showed that manipulating identity undermining lead to increased support for separatism. Finally, the fourth and the fifth (experimental) studies suggested that identity constructions, in the form of judgements of group prototypicality, can vary as a function of the strategic claim made by participants. In conclusion, the merits are stressed of an approach to identity processes and attitudes towards supra-national bodies that is sensitive to both context and content. It is also stressed that context and contents should not be taken as perceptual givens but as actively constructed by social actors.Money and 'self' : towards a social psychology of money and its usageSonnenberg, Stefaniehttps://hdl.handle.net/10023/141922019-04-01T10:41:13Z2003-01-01T00:00:00ZThis thesis contends that the subjective meanings and value attached to money may, in part, be a function of identity-related norms and values. This proposed relationship between identity issues and monetary attitudes/behaviour is explored across a series of methodologically diverse studies. It is argued that psychological approaches to money, despite their efforts to the contrary, frequently concur with traditional economic models of human behaviour in so far as they rest on similarly static, de-contextualised notions of the self. The research described here aims to substitute these implicit assumptions about the nature of selfhood with a social psychological account of the 'self and thus with an explicit focus on subjective identification processes, ha doing so, the present approach draws on the Social Identity tradition. First, findings from an exploratory interview study illustrate a) that identity concerns are central for people's understandings of money, b) that the relationship between money and selfhood is dilemmatic, and c) that money meanings and usage relate to identity across different levels of abstractions (i.e. personal, social, human). Second, a series of experimental studies (based on predictions derived from the Social Identity model of the self) shows that attitudes towards money can vary as a function of both social identity salience and the comparative context in which a given identity is salient. The association between social identification, specific identity contents and monetary attitudes is also addressed. Finally, an exploration of the relationship between identity concerns and decision-making processes within a Prisoner's Dilemma-type setting indicates that identity and the social knowledge derived from it play a crucial role, not only with regard to how people attempt to meet their goals in this context but also in terms of how these goals are defined. The broader implication of these findings with regard to 'rational choice' models of human agency are discussed.
2003-01-01T00:00:00ZSonnenberg, StefanieThis thesis contends that the subjective meanings and value attached to money may, in part, be a function of identity-related norms and values. This proposed relationship between identity issues and monetary attitudes/behaviour is explored across a series of methodologically diverse studies. It is argued that psychological approaches to money, despite their efforts to the contrary, frequently concur with traditional economic models of human behaviour in so far as they rest on similarly static, de-contextualised notions of the self. The research described here aims to substitute these implicit assumptions about the nature of selfhood with a social psychological account of the 'self and thus with an explicit focus on subjective identification processes, ha doing so, the present approach draws on the Social Identity tradition. First, findings from an exploratory interview study illustrate a) that identity concerns are central for people's understandings of money, b) that the relationship between money and selfhood is dilemmatic, and c) that money meanings and usage relate to identity across different levels of abstractions (i.e. personal, social, human). Second, a series of experimental studies (based on predictions derived from the Social Identity model of the self) shows that attitudes towards money can vary as a function of both social identity salience and the comparative context in which a given identity is salient. The association between social identification, specific identity contents and monetary attitudes is also addressed. Finally, an exploration of the relationship between identity concerns and decision-making processes within a Prisoner's Dilemma-type setting indicates that identity and the social knowledge derived from it play a crucial role, not only with regard to how people attempt to meet their goals in this context but also in terms of how these goals are defined. The broader implication of these findings with regard to 'rational choice' models of human agency are discussed.The transmission and evolution of human cultureMesoudi, Alexhttps://hdl.handle.net/10023/139552019-04-01T10:41:53Z2005-01-01T00:00:00Z'Culture' is defined as information, such as knowledge, beliefs, skills, attitudes or values, that is passed from individual to individual via social (or cultural) transmission and expressed in behaviour or artifacts. 'Cultural evolution' holds that this cultural inheritance system is governed by the same Darwinian processes as gene-based biological evolution. In Part A of this thesis it is argued that as compelling a case can now be made for a Darwinian theory of cultural evolution as Darwin himself presented in The Origin Of Species for biological evolution, If culture does indeed evolve, then it follows that the structure of a science of cultural evolution should broadly resemble that of the science of biological evolution. Hence Part A concludes by outlining a unified science of cultural evolution based on the sub-disciplines of evolutionary biology. Parts B and C comprise original empirical and theoretical work constituting two branches of this science of cultural evolution. Part B describes a series of experiments testing for a number of hypothesised biases in cultural transmission. Evidence was found for a 'social bias' that acts to promote information concerning third-party social relationships over equivalent non-social information, and a 'hierarchical bias' that acts to transform knowledge of everyday events from low-level actions into higher-level goals. Three other hypothesised biases concerning status, anthropomorphism and neoteny were not supported, although each gave rise to potential, future work using this methodology. Part C presents a theoretical investigation into the coevolution of the genetic bases of human mating behaviour and culturally inherited folk beliefs regarding paternity. Gene-culture coevolution and agent-based models suggested that beliefs in 'partible paternity' (that more than one man can father a child) create a new more polygamous form of society compared with beliefs in singular paternity (that only one man can father a child).
2005-01-01T00:00:00ZMesoudi, Alex'Culture' is defined as information, such as knowledge, beliefs, skills, attitudes or values, that is passed from individual to individual via social (or cultural) transmission and expressed in behaviour or artifacts. 'Cultural evolution' holds that this cultural inheritance system is governed by the same Darwinian processes as gene-based biological evolution. In Part A of this thesis it is argued that as compelling a case can now be made for a Darwinian theory of cultural evolution as Darwin himself presented in The Origin Of Species for biological evolution, If culture does indeed evolve, then it follows that the structure of a science of cultural evolution should broadly resemble that of the science of biological evolution. Hence Part A concludes by outlining a unified science of cultural evolution based on the sub-disciplines of evolutionary biology. Parts B and C comprise original empirical and theoretical work constituting two branches of this science of cultural evolution. Part B describes a series of experiments testing for a number of hypothesised biases in cultural transmission. Evidence was found for a 'social bias' that acts to promote information concerning third-party social relationships over equivalent non-social information, and a 'hierarchical bias' that acts to transform knowledge of everyday events from low-level actions into higher-level goals. Three other hypothesised biases concerning status, anthropomorphism and neoteny were not supported, although each gave rise to potential, future work using this methodology. Part C presents a theoretical investigation into the coevolution of the genetic bases of human mating behaviour and culturally inherited folk beliefs regarding paternity. Gene-culture coevolution and agent-based models suggested that beliefs in 'partible paternity' (that more than one man can father a child) create a new more polygamous form of society compared with beliefs in singular paternity (that only one man can father a child).Sharing and fairness in developmentRochat, PhilippeRobbins, Erinhttps://hdl.handle.net/10023/138342023-07-24T14:30:22Z2016-12-07T00:00:00Z2016-12-07T00:00:00ZRochat, PhilippeRobbins, ErinEmpirical and methodological investigations into novelty and familiarity as separate processes that support recognition memory in rats and humansSivakumaran, Magali H.https://hdl.handle.net/10023/137852019-05-02T11:01:26Z2018-06-29T00:00:00ZThere is a prevalent assumption in the recognition memory literature that the terms “novelty” and “familiarity” are words ascribed to differing extremities of a single memory strength continuum. The aim of the current thesis was to integrate experimental methodologies across human and rodents to further investigate novelty processing at both a cognitive and neural level, and assess whether it is dissociable from familiarity processing. This dissociation was questioned at a cognitive level in human participants in Experiments 1 to 3 and at a neural level in rats in Experiment 4 and 5. Participants were found to differentially assess novelty and familiarity when making confidence judgements about the mnemonic status of an item (Experiment 1). Additionally, novelty and familiarity processing for questioned items were found to be dissimilarly affected by the presence of a concurrent item of varying mnemonic statuses (Experiment 2 and 3). The presence of a concurrent familiar item did not impact novelty processing in the perirhinal cortex (Experiment 4 and 5), yet disrupted the neural networks established to be differentially engaged by novelty and familiarity (Experiment 5). These findings challenge the assumption that the terms “novelty” and “familiarity” relate to a single recognition memory process. Finally, to allow integration of the findings from the human and rodent experiments, the relationship between measures or recognition memory obtained from spontaneous object recognition (SOR) task in rats and recognition memory measures estimated from signal-detection based models of recognition memory in humans was investigated (Experiment 6 and 7). This revealed that novelty preference in the SOR was positively correlated to measures of recognition memory sensitivity, but not bias. Thus, this thesis argues for the future inclusion of a novelty as a dissociable process from familiarity in our understanding of recognition memory, and for the integrations of experimental methodologies used to test recognition memory across species.
2018-06-29T00:00:00ZSivakumaran, Magali H.There is a prevalent assumption in the recognition memory literature that the terms “novelty” and “familiarity” are words ascribed to differing extremities of a single memory strength continuum. The aim of the current thesis was to integrate experimental methodologies across human and rodents to further investigate novelty processing at both a cognitive and neural level, and assess whether it is dissociable from familiarity processing. This dissociation was questioned at a cognitive level in human participants in Experiments 1 to 3 and at a neural level in rats in Experiment 4 and 5. Participants were found to differentially assess novelty and familiarity when making confidence judgements about the mnemonic status of an item (Experiment 1). Additionally, novelty and familiarity processing for questioned items were found to be dissimilarly affected by the presence of a concurrent item of varying mnemonic statuses (Experiment 2 and 3). The presence of a concurrent familiar item did not impact novelty processing in the perirhinal cortex (Experiment 4 and 5), yet disrupted the neural networks established to be differentially engaged by novelty and familiarity (Experiment 5). These findings challenge the assumption that the terms “novelty” and “familiarity” relate to a single recognition memory process. Finally, to allow integration of the findings from the human and rodent experiments, the relationship between measures or recognition memory obtained from spontaneous object recognition (SOR) task in rats and recognition memory measures estimated from signal-detection based models of recognition memory in humans was investigated (Experiment 6 and 7). This revealed that novelty preference in the SOR was positively correlated to measures of recognition memory sensitivity, but not bias. Thus, this thesis argues for the future inclusion of a novelty as a dissociable process from familiarity in our understanding of recognition memory, and for the integrations of experimental methodologies used to test recognition memory across species.An investigation into the relations between association and intelligenceYule, Ella Pratthttps://hdl.handle.net/10023/131732019-04-01T10:40:46Z1933-01-01T00:00:00Z1933-01-01T00:00:00ZYule, Ella PrattSexual selection and the human face : beauty in the face of the beheld and in the eye of the beholderLittle, Anthony Charleshttps://hdl.handle.net/10023/131452019-04-01T10:41:30Z2004-06-01T00:00:00ZEvolutionary theory has been proposed to provide an answer to the question of why some faces are perceived to be more attractive than others are. The first part of this thesis provides an introduction to an evolutionary approach to studying attractiveness (Chapter 1) and reviews sexual selection theory (Chapter 2) and how this theory has been applied to help understand human facial attractiveness (Chapter 3). The thesis focuses particularly on symmetry and secondary sexual characteristics in faces, two of the main factors that relate to attractiveness from an evolutionary perspective as they are both proposed to be associated with genetic benefits to the choosing individual. The empirical work in the first part of the thesis is consistent with both masculinity and symmetry in males reflecting adaptive selection for high quality mates. Facial masculinity was found to be associated with personality attributions that appear consistent with masculinity reflecting testosterone level in males. Masculinity was associated with some negative personality attributions and when controlling for such attributions masculinity in male faces was found to be of increased attractiveness (Chapter 4). Facial symmetry was found to be preferred in opposite-sex faces by both males and females when images were presented upright and less so when the images were inverted (Chapter 5). Symmetry was also found to be preferred in familiar faces and both this preference and preferences differing according orientation are consistent with the notion that symmetry preferences are an adaptation to identify high quality mates. The second part of this thesis presents views on the existence of individual differences in attractiveness judgements that are consistent with evolutionary theory. Evidence is reviewed regarding how individual differences in preference could be more adaptive than a single species wide strategy (Chapter 6). Chapters 7 and 8 present studies showing that preferences for sexual dimorphism and symmetry differ between women in ways that may have been adaptive over evolutionary time. Women who are attractive prefer higher levels of masculinity and symmetry than less attractive women (Chapter 7) and women judging for short-term relationships or women who already have current partners prefer more masculinity in male faces than those judging for long-term relationships or women who do not have a partner (Chapter 8). Chapter 9 again shows that individual differences in mate-choice do exist and can be consistent with evolutionary theory showing that individuals choose partners resembling their opposite-sex parent, a phenomenon that may reflect imprinting-like effects in humans. This thesis presents data that is consistent with the notion that sexual dimorphism and symmetry may advertise quality in human faces (Part 1) and data on several potentially adaptive individual differences in human face preferences (Part 2). Individuals can both agree, on average, on what is attractive and unattractive and yet still demonstrate variation in judgements. In this way beauty can be said to be both in the face of the beheld and in the eye of beholder.
2004-06-01T00:00:00ZLittle, Anthony CharlesEvolutionary theory has been proposed to provide an answer to the question of why some faces are perceived to be more attractive than others are. The first part of this thesis provides an introduction to an evolutionary approach to studying attractiveness (Chapter 1) and reviews sexual selection theory (Chapter 2) and how this theory has been applied to help understand human facial attractiveness (Chapter 3). The thesis focuses particularly on symmetry and secondary sexual characteristics in faces, two of the main factors that relate to attractiveness from an evolutionary perspective as they are both proposed to be associated with genetic benefits to the choosing individual. The empirical work in the first part of the thesis is consistent with both masculinity and symmetry in males reflecting adaptive selection for high quality mates. Facial masculinity was found to be associated with personality attributions that appear consistent with masculinity reflecting testosterone level in males. Masculinity was associated with some negative personality attributions and when controlling for such attributions masculinity in male faces was found to be of increased attractiveness (Chapter 4). Facial symmetry was found to be preferred in opposite-sex faces by both males and females when images were presented upright and less so when the images were inverted (Chapter 5). Symmetry was also found to be preferred in familiar faces and both this preference and preferences differing according orientation are consistent with the notion that symmetry preferences are an adaptation to identify high quality mates. The second part of this thesis presents views on the existence of individual differences in attractiveness judgements that are consistent with evolutionary theory. Evidence is reviewed regarding how individual differences in preference could be more adaptive than a single species wide strategy (Chapter 6). Chapters 7 and 8 present studies showing that preferences for sexual dimorphism and symmetry differ between women in ways that may have been adaptive over evolutionary time. Women who are attractive prefer higher levels of masculinity and symmetry than less attractive women (Chapter 7) and women judging for short-term relationships or women who already have current partners prefer more masculinity in male faces than those judging for long-term relationships or women who do not have a partner (Chapter 8). Chapter 9 again shows that individual differences in mate-choice do exist and can be consistent with evolutionary theory showing that individuals choose partners resembling their opposite-sex parent, a phenomenon that may reflect imprinting-like effects in humans. This thesis presents data that is consistent with the notion that sexual dimorphism and symmetry may advertise quality in human faces (Part 1) and data on several potentially adaptive individual differences in human face preferences (Part 2). Individuals can both agree, on average, on what is attractive and unattractive and yet still demonstrate variation in judgements. In this way beauty can be said to be both in the face of the beheld and in the eye of beholder.The role of apparent health in face preferencesJones, Benedict Christopherhttps://hdl.handle.net/10023/131442019-04-01T10:40:27Z2005-06-01T00:00:00ZThis thesis describes a series of empirical studies that investigated the role of apparent health in face preferences. Chapter 1 summarises previous work showing that facial symmetry, averageness and sexual dimorphism influence judgements of facial attractiveness. Chapter 2 describes studies demonstrating that consideration of the role of apparent health in face preferences offers insight into the motivations that underpin attraction to symmetric faces. Chapters 3-5 describe studies demonstrating that, while people generally prefer faces that appear healthy to those that appear unhealthy, characteristics of the judges (e.g. hormonal, health and developmental factors) contribute to systematic variation in women's preferences for apparent health. In the final chapter, a positive link between lifestyle health (e.g. exercise behaviour) and facial health was demonstrated. The findings described in this thesis are evidence that preferences for healthy faces are influenced by biological factors and evidence for accuracy in attributions of health to faces.
2005-06-01T00:00:00ZJones, Benedict ChristopherThis thesis describes a series of empirical studies that investigated the role of apparent health in face preferences. Chapter 1 summarises previous work showing that facial symmetry, averageness and sexual dimorphism influence judgements of facial attractiveness. Chapter 2 describes studies demonstrating that consideration of the role of apparent health in face preferences offers insight into the motivations that underpin attraction to symmetric faces. Chapters 3-5 describe studies demonstrating that, while people generally prefer faces that appear healthy to those that appear unhealthy, characteristics of the judges (e.g. hormonal, health and developmental factors) contribute to systematic variation in women's preferences for apparent health. In the final chapter, a positive link between lifestyle health (e.g. exercise behaviour) and facial health was demonstrated. The findings described in this thesis are evidence that preferences for healthy faces are influenced by biological factors and evidence for accuracy in attributions of health to faces.Sexual dimorphism in faces across development through early adulthood : perceptions, attributions and stabilityCornwell, Robin Elisabethhttps://hdl.handle.net/10023/131432019-04-01T10:42:10Z2005-10-01T00:00:00ZIn this thesis, I use a Darwinian approach to explore the role of sexual-dimorphism in human behaviour across development and into early adulthood, and its impact on adult mating-strategies. In Studies 1-2, I explore the importance of heredity and developmental stability of facial characteristics in light of theories of sexual selection. Using family photos, judgements of faces of parents and offspring revealed that facial sexual-dimorphism is passed on from father to son and mother to daughter, while inheritance of attractiveness is apparent only in daughters. I also examine the stability of facial appearance across development (infancy, childhood, young-adult), and find that sexual-dimorphism remains stable for both sexes, while attractiveness is stable only in females. Feminine characteristics are perceived as attractive in infant faces, and feminine characteristics have been perceived as looking more neotenous. In light of these data, I develop a theory for increased preferences for neoteny in human infants (Chapter 4). In studies 3-4, I examine the developmental milestones, puberty and first sexual intercourse in relationship to adult mate-choice strategies. Women who experience first coitus early prefer increased facial-masculinity in potential mates. In men, both early coitus and early puberty relate to increased preferences for facial-femininity in potential mates. In study 5, I look at attributions of peri-pubertal children (aged 11-12 years) to peer faces manipulated on sexually-dimorphic features. Children's attractiveness judgements show evidence of adult-like preferences, with boys preferring feminine girls' faces and girls preferring feminised boys' faces. Both girls and boys attribute the negative stereotype of bullying to more masculinised boys' faces. Study 6 concerns the relationship between two modalities of sexual-dimorphism, pheromones and facial characteristics. Adults indicate preferences from a continuum of sexually-dimorphic face-shapes, in addition to rating sex-specific pheromones on pleasantness. Individuals who prefer sex-typical facial characteristics in opposite-sex faces also judged the sex-typical pheromone as more pleasant.
2005-10-01T00:00:00ZCornwell, Robin ElisabethIn this thesis, I use a Darwinian approach to explore the role of sexual-dimorphism in human behaviour across development and into early adulthood, and its impact on adult mating-strategies. In Studies 1-2, I explore the importance of heredity and developmental stability of facial characteristics in light of theories of sexual selection. Using family photos, judgements of faces of parents and offspring revealed that facial sexual-dimorphism is passed on from father to son and mother to daughter, while inheritance of attractiveness is apparent only in daughters. I also examine the stability of facial appearance across development (infancy, childhood, young-adult), and find that sexual-dimorphism remains stable for both sexes, while attractiveness is stable only in females. Feminine characteristics are perceived as attractive in infant faces, and feminine characteristics have been perceived as looking more neotenous. In light of these data, I develop a theory for increased preferences for neoteny in human infants (Chapter 4). In studies 3-4, I examine the developmental milestones, puberty and first sexual intercourse in relationship to adult mate-choice strategies. Women who experience first coitus early prefer increased facial-masculinity in potential mates. In men, both early coitus and early puberty relate to increased preferences for facial-femininity in potential mates. In study 5, I look at attributions of peri-pubertal children (aged 11-12 years) to peer faces manipulated on sexually-dimorphic features. Children's attractiveness judgements show evidence of adult-like preferences, with boys preferring feminine girls' faces and girls preferring feminised boys' faces. Both girls and boys attribute the negative stereotype of bullying to more masculinised boys' faces. Study 6 concerns the relationship between two modalities of sexual-dimorphism, pheromones and facial characteristics. Adults indicate preferences from a continuum of sexually-dimorphic face-shapes, in addition to rating sex-specific pheromones on pleasantness. Individuals who prefer sex-typical facial characteristics in opposite-sex faces also judged the sex-typical pheromone as more pleasant.Early development of strategies for mapping symbol-referent relations : what do young children understand about scale models?Solomon, Tracy L.https://hdl.handle.net/10023/131422019-04-01T10:41:45Z2001-11-01T00:00:00ZThe research reported here investigated the nature of young children's understanding of a novel symbol-a scale model. Children witnessed the hiding of a small toy in a scale model of a room and were then required to search for an analogous larger toy that had been surreptitiously hidden in the actual room. At issue was whether children succeed by attending to the target location (object strategy), to the spatial location of the target location (spatial strategy), or to both types of information. It has been suggested that at three years of age (the age at which children first succeed on the task) children succeed by recognizing the correspondence between analogous objects in the two spaces (Bence & Presson, 1997; Blades & Cooke, 1994; Perner, 1991; Lillard, 1993) but that an understanding of the model as a whole as a representation of the room necessitates also attending to the spatial relations between the objects (Perner, 1991; Lillard, 1993). In five Experiments, children participated in versions of the model task that varied in the type of information (object and/or spatial) available to solve the task. The results revealed that although, in general, children rely primarily on the identity of the individual objects to find the hidden toy, the spatial relations between the objects may also influence task success. Furthermore, there was strong evidence of individual differences in children's strategies which appeared to be linked to sex, with girls attending primarily to the identity of the objects and boys demonstrating a fledgling ability to approach the model spatially. Some children also appeared to label the target object but the labeling strategy could not account for girls' tendency to attend to the objects more than boys. It is suggested that characterizations of an abrupt shift between three and four years of age in the ability to interpret the model as a whole as a representation of the room may be misleading. There may be multiple developmental routes to the gradual acquisition of an explicit understanding of a scale model as a symbol for the space it is intended to represent.
2001-11-01T00:00:00ZSolomon, Tracy L.The research reported here investigated the nature of young children's understanding of a novel symbol-a scale model. Children witnessed the hiding of a small toy in a scale model of a room and were then required to search for an analogous larger toy that had been surreptitiously hidden in the actual room. At issue was whether children succeed by attending to the target location (object strategy), to the spatial location of the target location (spatial strategy), or to both types of information. It has been suggested that at three years of age (the age at which children first succeed on the task) children succeed by recognizing the correspondence between analogous objects in the two spaces (Bence & Presson, 1997; Blades & Cooke, 1994; Perner, 1991; Lillard, 1993) but that an understanding of the model as a whole as a representation of the room necessitates also attending to the spatial relations between the objects (Perner, 1991; Lillard, 1993). In five Experiments, children participated in versions of the model task that varied in the type of information (object and/or spatial) available to solve the task. The results revealed that although, in general, children rely primarily on the identity of the individual objects to find the hidden toy, the spatial relations between the objects may also influence task success. Furthermore, there was strong evidence of individual differences in children's strategies which appeared to be linked to sex, with girls attending primarily to the identity of the objects and boys demonstrating a fledgling ability to approach the model spatially. Some children also appeared to label the target object but the labeling strategy could not account for girls' tendency to attend to the objects more than boys. It is suggested that characterizations of an abrupt shift between three and four years of age in the ability to interpret the model as a whole as a representation of the room may be misleading. There may be multiple developmental routes to the gradual acquisition of an explicit understanding of a scale model as a symbol for the space it is intended to represent.Processing of emotional material in major depression : cognitive and neuropsychological investigationsRidout, Nathanhttps://hdl.handle.net/10023/131412019-04-01T10:41:36Z2005-01-01T00:00:00ZThe aim of this thesis was to expand the existing knowledge base concerning the profile of emotional processing that is associated with major depression, particularly in terms of socially important non-verbal stimuli (e.g. emotional facial expressions). Experiment one utilised a face-word variant of the emotional Stroop task and demonstrated that depressed patients (DP) did not exhibit a selective attention bias for sad faces. Conversely, the healthy controls (HC) were shown to selectively attend to happy faces. At recognition memory testing, DP did not exhibit a memory bias for depression-relevant words, but did demonstrate a tendency to falsely recognise depression-relevant words that had not been presented at encoding. Experiment two examined the pattern of autobiographical memory (ABM) retrieval exhibited by DP and HC in response to verbal (words) and non-verbal (images & faces) affective cues. DP were slower than HC to retrieve positive ABMs, but did not differ from HC in their retrieval times for negative ABMs. Overall, DP retrieved fewer specific ABMs than did the HC. Participants retrieved more specific ABMs to image cues than to words or faces, but this pattern was only demonstrated by the HC. Reduced retrieval of specific ABMs by DP was a consequence of increased retrieval of categorical ABMs; this tendency was particularly marked when the participants were cued with faces. During experiment three, DP and HC were presented with a series of faces and were asked to identify the gender of the person featured in each photograph. Overall, gender identification times were not affected by the emotion portrayed by the faces. Furthermore at subsequent recognition memory testing, DP did not exhibit MCM bias for sad faces. During experiment four, DP and HC were presented with videotaped depictions of 'realistic' social interactions and were asked to identify the emotion portrayed by the characters and to make inferences about the thoughts, intentions and beliefs of these individuals. Overall, DP were impaired in their recognition of happiness and in understanding social interactions involving sarcasm and deception. Correct social inference was significantly related to both executive function and depression severity. Experiment five involved assessing a group of eight patients that had undergone neurosurgery for chronic, treatment-refractory depression on the identical emotion recognition and social perception tasks that were utilised in experiment four. Relative to HC, surgery patients (SP) exhibited general deficits on all emotion recognition and social processing tasks. Notably, depression status did not appear to interact with surgery status to worsen these observed deficits. These findings suggest that the anterior cingulate region of the prefrontal cortex may play a role in correct social inference.
Summary: Taken together the findings of the five experimental studies of the thesis demonstrate that, in general, biases that have been observed in DP processing of affective verbal material generalise to non-verbal emotional material (e.g. emotional faces). However, there are a number of marked differences that have been highlighted throughout the thesis. There is also evidence that biased emotional processing in DP requires explicit processing of the emotional content of the stimuli. Furthermore, a central theme of the thesis is that deficits in executive function in DP appear to be implicated in the impairments of emotional processing that are exhibited by these patients.
2005-01-01T00:00:00ZRidout, NathanThe aim of this thesis was to expand the existing knowledge base concerning the profile of emotional processing that is associated with major depression, particularly in terms of socially important non-verbal stimuli (e.g. emotional facial expressions). Experiment one utilised a face-word variant of the emotional Stroop task and demonstrated that depressed patients (DP) did not exhibit a selective attention bias for sad faces. Conversely, the healthy controls (HC) were shown to selectively attend to happy faces. At recognition memory testing, DP did not exhibit a memory bias for depression-relevant words, but did demonstrate a tendency to falsely recognise depression-relevant words that had not been presented at encoding. Experiment two examined the pattern of autobiographical memory (ABM) retrieval exhibited by DP and HC in response to verbal (words) and non-verbal (images & faces) affective cues. DP were slower than HC to retrieve positive ABMs, but did not differ from HC in their retrieval times for negative ABMs. Overall, DP retrieved fewer specific ABMs than did the HC. Participants retrieved more specific ABMs to image cues than to words or faces, but this pattern was only demonstrated by the HC. Reduced retrieval of specific ABMs by DP was a consequence of increased retrieval of categorical ABMs; this tendency was particularly marked when the participants were cued with faces. During experiment three, DP and HC were presented with a series of faces and were asked to identify the gender of the person featured in each photograph. Overall, gender identification times were not affected by the emotion portrayed by the faces. Furthermore at subsequent recognition memory testing, DP did not exhibit MCM bias for sad faces. During experiment four, DP and HC were presented with videotaped depictions of 'realistic' social interactions and were asked to identify the emotion portrayed by the characters and to make inferences about the thoughts, intentions and beliefs of these individuals. Overall, DP were impaired in their recognition of happiness and in understanding social interactions involving sarcasm and deception. Correct social inference was significantly related to both executive function and depression severity. Experiment five involved assessing a group of eight patients that had undergone neurosurgery for chronic, treatment-refractory depression on the identical emotion recognition and social perception tasks that were utilised in experiment four. Relative to HC, surgery patients (SP) exhibited general deficits on all emotion recognition and social processing tasks. Notably, depression status did not appear to interact with surgery status to worsen these observed deficits. These findings suggest that the anterior cingulate region of the prefrontal cortex may play a role in correct social inference.
Summary: Taken together the findings of the five experimental studies of the thesis demonstrate that, in general, biases that have been observed in DP processing of affective verbal material generalise to non-verbal emotional material (e.g. emotional faces). However, there are a number of marked differences that have been highlighted throughout the thesis. There is also evidence that biased emotional processing in DP requires explicit processing of the emotional content of the stimuli. Furthermore, a central theme of the thesis is that deficits in executive function in DP appear to be implicated in the impairments of emotional processing that are exhibited by these patients.Studies of emotion recognition from multiple communication channelsDurrani, Sophia J.https://hdl.handle.net/10023/131402019-04-01T10:42:03Z2005-01-01T00:00:00ZCrucial to human interaction and development, emotions have long fascinated psychologists. Current thinking suggests that specific emotions, regardless of the channel in which they are communicated, are processed by separable neural mechanisms. Yet much research has focused only on the interpretation of facial expressions of emotion. The present research addressed this oversight by exploring recognition of emotion from facial, vocal, and gestural tasks. Happiness and disgust were best conveyed by the face, yet other emotions were equally well communicated by voices and gestures. A novel method for exploring emotion perception, by contrasting errors, is proposed. Studies often fail to consider whether the status of the perceiver affects emotion recognition abilities. Experiments presented here revealed an impact of mood, sex, and age of participants. Dysphoric mood was associated with difficulty in interpreting disgust from vocal and gestural channels. To some extent, this supports the concept that neural regions are specialised for the perception of disgust. Older participants showed decreased emotion recognition accuracy but no specific pattern of recognition difficulty. Sex of participant and of actor affected emotion recognition from voices. In order to examine neural mechanisms underlying emotion recognition, an exploration was undertaken using emotion tasks with Parkinson's patients. Patients showed no clear pattern of recognition impairment across channels of communication. In this study, the exclusion of surprise as a stimulus and response option in a facial emotion recognition task yielded results contrary to those achieved without this modification. Implications for this are discussed. Finally, this thesis gives rise to three caveats for neuropsychological research. First, the impact of the observers' status, in terms of mood, age, and sex, should not be neglected. Second, exploring multiple channels of communication is important for understanding emotion perception. Third, task design should be appraised before conclusions regarding impairments in emotion perception are presumed.
2005-01-01T00:00:00ZDurrani, Sophia J.Crucial to human interaction and development, emotions have long fascinated psychologists. Current thinking suggests that specific emotions, regardless of the channel in which they are communicated, are processed by separable neural mechanisms. Yet much research has focused only on the interpretation of facial expressions of emotion. The present research addressed this oversight by exploring recognition of emotion from facial, vocal, and gestural tasks. Happiness and disgust were best conveyed by the face, yet other emotions were equally well communicated by voices and gestures. A novel method for exploring emotion perception, by contrasting errors, is proposed. Studies often fail to consider whether the status of the perceiver affects emotion recognition abilities. Experiments presented here revealed an impact of mood, sex, and age of participants. Dysphoric mood was associated with difficulty in interpreting disgust from vocal and gestural channels. To some extent, this supports the concept that neural regions are specialised for the perception of disgust. Older participants showed decreased emotion recognition accuracy but no specific pattern of recognition difficulty. Sex of participant and of actor affected emotion recognition from voices. In order to examine neural mechanisms underlying emotion recognition, an exploration was undertaken using emotion tasks with Parkinson's patients. Patients showed no clear pattern of recognition impairment across channels of communication. In this study, the exclusion of surprise as a stimulus and response option in a facial emotion recognition task yielded results contrary to those achieved without this modification. Implications for this are discussed. Finally, this thesis gives rise to three caveats for neuropsychological research. First, the impact of the observers' status, in terms of mood, age, and sex, should not be neglected. Second, exploring multiple channels of communication is important for understanding emotion perception. Third, task design should be appraised before conclusions regarding impairments in emotion perception are presumed.Inhibitory processes in the misinformation effect : negative consequences of an adaptive processSaunders, Johttps://hdl.handle.net/10023/131222019-04-01T10:40:09Z2004-01-01T00:00:00ZRecent research has suggested the seemingly ironic possibility that in order to be able to remember effectively, we must be able to forget. Despite the fact that forgetting is typically conceived of as a wholly negative experience it may, nonetheless, have adaptive consequences for the efficient updating of memory. Without a method for setting aside out-of-date or unwanted information, we may be unable to satisfy current memorial goals. Recent research suggests that inhibitory processes operating during retrieval may be responsible for the temporary forgetting of unwanted information so that desired memories can be successfully retrieved (referred to as retrieval-induced forgetting, M.C. Anderson, Bjork & Bjork, 1994).
The present thesis attempts to enhance our understanding of the basic mechanisms that underlie our ability to update our memories by examining the role of inhibitory processes in the misinformation effect. The misinformation effect is a form of memory error whereby individuals mistakenly report post-event misleading information rather than information that was originally encoded during an initial study phase (e.g., E.F. Loftus, 1979a). In order to examine whether the underlying mechanisms in the misinformation effect (and more generally in memory updating) are inhibitory in nature, five theory-driven experiments were conducted and reported in this thesis.
An inhibitory account of misinformation effects assumes that significant misinformation effects should only be detected when information from an initial event has been inhibited, and therefore is unavailable to conscious inspection. A new paradigm was designed for investigating the memorial processes responsible for the misinformation effect, which combined key features from the retrieval practice paradigm with that of the misinformation paradigm (cf. E.F. Loftus, Miller & Burns, 1978). In Experiments 1 and 2, the boundary conditions of varying the retrieval status of target items within this new paradigm were explored. More specifically, in Experiment 1, significant misinformation effects were found only when misleading information was presented on items that were subject to retrieval-induced forgetting, i.e., the original information was unavailable to conscious inspection, leaving only the post-event information available for retrieval. A further test of the retrieval-induced forgetting account was examined in Experiment 2 whereby the presence of retrieval induced forgetting was manipulated through the insertion of a delay. Experiment 2 indicated that the production of misinformation effects was dependent on retrieval-induced forgetting remaining active (i.e., under condition of no delay, or where a delay occurred between study and retrieval practice). In contrast, significant misinformation effects were not found when retrieval-induced forgetting dissipated over a retention interval (i.e., when a delay was inserted between retrieval practice and final test).
Despite Experiments 1 - 2 suggesting that retrieval-induced forgetting may play an influential role in the production of misinformation effect, the new misinformation paradigm cannot differentiate between the possible inhibitory and non-inhibitory processes that may underlie retrieval-induced forgetting. This is primarily due to the new paradigm employing a free recall test rather than using a memory test that can separate the actions of inhibitory from non-inhibitory processes.
However, as the ‘independent probe’ method (M.C. Anderson & Spellman, 1995) can perform this task, it was modified for use in Experiments 3 - 5 , which more closely examined whether inhibitory processes were indeed responsible for both retrieval-induced forgetting and misinformation effects. More specifically. Experiment 3 found that inhibitory processes were the primary mechanism behind retrieval-induced forgetting, while Experiment 4 demonstrated that any item that competes with target material for retrieval is subject to inhibition (referred to as cross-category and second-order inhibition). Experiment 5 extended the findings of Experiment 3 and 4, and found that inhibitory processes were not only responsible for misinformation effects, but that all inhibited information is susceptible to the effects of post-event information. The present studies suggest that that an adaptive function on inhibition
(i.e., the updating of memory) may be responsible for unwanted and undesired effect in memory under certain circumstances (i.e., the production of misinformation effects and eyewitness errors).
In order to examine more fully the role of inhibitory processes in the production of misinformation effects, and more generally, in memory updating, the present thesis considers both classical and modern research on forgetting. Chapter 1 outlines recent theorising that forgetting should not be considered an exclusively negative phenomenon, and that it should, in fact, be considered an essential and necessary process that keeps our memory systems running optimally. This possibility is examined in more thorough detail in Chapters 2 and 3. Chapter 2 considers both classical interference research, and the more recent inhibitory accounts of intentional forgetting, while Chapter 3 examines how successful these inhibitory accounts have been applied to research concerning unintentional forgetting. In contrast. Chapter 4 examines a rather different approach to memory updating as viewed through misinformation studies. A new paradigm for investigating misinformation effects is introduced in Chapter 5, and the empirical Chapters 5 - 9 discuss the application of this new paradigm to the investigation of misinformation effects. Finally, the conclusions and implications of unintentional forgetting for theories of memory updating are discussed in Chapter 10. The work presented in this thesis suggests that not only can inhibition promote the updating of memory, but it can also leave our memories vulnerable to the unintentional integration of incorrect information.
2004-01-01T00:00:00ZSaunders, JoRecent research has suggested the seemingly ironic possibility that in order to be able to remember effectively, we must be able to forget. Despite the fact that forgetting is typically conceived of as a wholly negative experience it may, nonetheless, have adaptive consequences for the efficient updating of memory. Without a method for setting aside out-of-date or unwanted information, we may be unable to satisfy current memorial goals. Recent research suggests that inhibitory processes operating during retrieval may be responsible for the temporary forgetting of unwanted information so that desired memories can be successfully retrieved (referred to as retrieval-induced forgetting, M.C. Anderson, Bjork & Bjork, 1994).
The present thesis attempts to enhance our understanding of the basic mechanisms that underlie our ability to update our memories by examining the role of inhibitory processes in the misinformation effect. The misinformation effect is a form of memory error whereby individuals mistakenly report post-event misleading information rather than information that was originally encoded during an initial study phase (e.g., E.F. Loftus, 1979a). In order to examine whether the underlying mechanisms in the misinformation effect (and more generally in memory updating) are inhibitory in nature, five theory-driven experiments were conducted and reported in this thesis.
An inhibitory account of misinformation effects assumes that significant misinformation effects should only be detected when information from an initial event has been inhibited, and therefore is unavailable to conscious inspection. A new paradigm was designed for investigating the memorial processes responsible for the misinformation effect, which combined key features from the retrieval practice paradigm with that of the misinformation paradigm (cf. E.F. Loftus, Miller & Burns, 1978). In Experiments 1 and 2, the boundary conditions of varying the retrieval status of target items within this new paradigm were explored. More specifically, in Experiment 1, significant misinformation effects were found only when misleading information was presented on items that were subject to retrieval-induced forgetting, i.e., the original information was unavailable to conscious inspection, leaving only the post-event information available for retrieval. A further test of the retrieval-induced forgetting account was examined in Experiment 2 whereby the presence of retrieval induced forgetting was manipulated through the insertion of a delay. Experiment 2 indicated that the production of misinformation effects was dependent on retrieval-induced forgetting remaining active (i.e., under condition of no delay, or where a delay occurred between study and retrieval practice). In contrast, significant misinformation effects were not found when retrieval-induced forgetting dissipated over a retention interval (i.e., when a delay was inserted between retrieval practice and final test).
Despite Experiments 1 - 2 suggesting that retrieval-induced forgetting may play an influential role in the production of misinformation effect, the new misinformation paradigm cannot differentiate between the possible inhibitory and non-inhibitory processes that may underlie retrieval-induced forgetting. This is primarily due to the new paradigm employing a free recall test rather than using a memory test that can separate the actions of inhibitory from non-inhibitory processes.
However, as the ‘independent probe’ method (M.C. Anderson & Spellman, 1995) can perform this task, it was modified for use in Experiments 3 - 5 , which more closely examined whether inhibitory processes were indeed responsible for both retrieval-induced forgetting and misinformation effects. More specifically. Experiment 3 found that inhibitory processes were the primary mechanism behind retrieval-induced forgetting, while Experiment 4 demonstrated that any item that competes with target material for retrieval is subject to inhibition (referred to as cross-category and second-order inhibition). Experiment 5 extended the findings of Experiment 3 and 4, and found that inhibitory processes were not only responsible for misinformation effects, but that all inhibited information is susceptible to the effects of post-event information. The present studies suggest that that an adaptive function on inhibition
(i.e., the updating of memory) may be responsible for unwanted and undesired effect in memory under certain circumstances (i.e., the production of misinformation effects and eyewitness errors).
In order to examine more fully the role of inhibitory processes in the production of misinformation effects, and more generally, in memory updating, the present thesis considers both classical and modern research on forgetting. Chapter 1 outlines recent theorising that forgetting should not be considered an exclusively negative phenomenon, and that it should, in fact, be considered an essential and necessary process that keeps our memory systems running optimally. This possibility is examined in more thorough detail in Chapters 2 and 3. Chapter 2 considers both classical interference research, and the more recent inhibitory accounts of intentional forgetting, while Chapter 3 examines how successful these inhibitory accounts have been applied to research concerning unintentional forgetting. In contrast. Chapter 4 examines a rather different approach to memory updating as viewed through misinformation studies. A new paradigm for investigating misinformation effects is introduced in Chapter 5, and the empirical Chapters 5 - 9 discuss the application of this new paradigm to the investigation of misinformation effects. Finally, the conclusions and implications of unintentional forgetting for theories of memory updating are discussed in Chapter 10. The work presented in this thesis suggests that not only can inhibition promote the updating of memory, but it can also leave our memories vulnerable to the unintentional integration of incorrect information.Victimisation and eyewitness memory : exploring the effects of physiological and psychological factorsWoolnough, Penny S.https://hdl.handle.net/10023/131212019-04-01T10:42:26Z2002-01-01T00:00:00ZThis thesis presents research designed to explore the role of physiological and psychological factors in mediating the effects of victimisation upon eyewitness memory. A tripartite model of arousal and memory is proposed encompassing physiological, psychological and motivational mechanisms. In order to investigate the potential role of these mechanisms, three laboratory based studies and one archival study are presented. The results of the laboratory studies suggest that physiological arousal may not influence eyewitness memory. In contrast, whilst direct support for an influence of psychological arousal is not provided, the possibility that psychological arousal may be an important factor cannot readily be dismissed. From a methodological perspective, contrary to existing laboratory-based research concerning visually-induced arousal, the results of the laboratory studies suggest that personal involvement may be an important factor influencing memory. Furthermore, the third laboratory study found that, differences in memory for emotional and neutral material may be a function of inherent differences between the material rather than an influence of arousal. Finally, in order to compare and contrast laboratory based research with the performance of real witnesses, a field based study utilising closed-circuit television to assess eyewitness accuracy for action details was conducted. In line with Studies One and Two, victims and bystanders were not found to differ in their memory performance. This study provides direct support for existing field and archival research suggesting that real victims and bystanders tend to be highly accurate in their eyewitness accounts. Taken together, the results of the research presented in this thesis suggest that whilst physiological arousal may not be an important factor influencing eyewitness memory, psychological and motivational influences may be important when witnesses are personally involved with the target incident.
2002-01-01T00:00:00ZWoolnough, Penny S.This thesis presents research designed to explore the role of physiological and psychological factors in mediating the effects of victimisation upon eyewitness memory. A tripartite model of arousal and memory is proposed encompassing physiological, psychological and motivational mechanisms. In order to investigate the potential role of these mechanisms, three laboratory based studies and one archival study are presented. The results of the laboratory studies suggest that physiological arousal may not influence eyewitness memory. In contrast, whilst direct support for an influence of psychological arousal is not provided, the possibility that psychological arousal may be an important factor cannot readily be dismissed. From a methodological perspective, contrary to existing laboratory-based research concerning visually-induced arousal, the results of the laboratory studies suggest that personal involvement may be an important factor influencing memory. Furthermore, the third laboratory study found that, differences in memory for emotional and neutral material may be a function of inherent differences between the material rather than an influence of arousal. Finally, in order to compare and contrast laboratory based research with the performance of real witnesses, a field based study utilising closed-circuit television to assess eyewitness accuracy for action details was conducted. In line with Studies One and Two, victims and bystanders were not found to differ in their memory performance. This study provides direct support for existing field and archival research suggesting that real victims and bystanders tend to be highly accurate in their eyewitness accounts. Taken together, the results of the research presented in this thesis suggest that whilst physiological arousal may not be an important factor influencing eyewitness memory, psychological and motivational influences may be important when witnesses are personally involved with the target incident.Retrieval-induced forgetting for person-specific informationAttrill, Alisonhttps://hdl.handle.net/10023/131202019-04-01T10:42:05Z2005-01-01T00:00:00ZRecent research has shown heightened interest in the potential role of inhibitory mechanisms in solving the multiple category problem associated with processing person-specific information. Inhibition has been proposed to control the activation saliency of one category of person-specific information over other activated categories to guide the processing, interpretation and behavioural responses to socially-relevant stimuli. The current research considers a) whether inhibition operates in a similar manner for both self- and other-referent information, and b) whether the inhibitory mechanism associated with laboratory-observed retrieval-induced forgetting is also involved in categorically thinking about the self and others. Participants studied and carried out guided retrieval practice on positive and negative self- and other-referent traits in seven studies that used variants of the retrieval practice paradigm. The observed patterns of forgetting were found to be consistent with the notion that retrieval inhibition operates in a flexible goal-directed manner to reduce the activation of person-specific information that carries little or no meaning for the social perceiver, regardless of whether that information relates to the self or to a target other. Consideration of the significance subjectively attributed to person information showed that both personally significant self information (Studies 4a,b, 5b) and highly informative other-referent material (Studies 2, 5b) are protected against active forgetting, whilst information of low diagnostic value succumbs to inhibitory processing. The goal-directed nature of active forgetting was also shown to operate in an implicit manner (Study 4a) which remained unaffected by attentional focus being brought to bear on target or non-target items (Study 4b). Two main conclusions are discussed, a) that both self- and other-referent information are protected against active forgetting where that information carries meaning for the social perceiver and becomes integrated into existing person-specific knowledge, and b) that both the retrieval practice procedure and the processes involved in categorical person perception may be subject to the same inhibitory mechanism.
2005-01-01T00:00:00ZAttrill, AlisonRecent research has shown heightened interest in the potential role of inhibitory mechanisms in solving the multiple category problem associated with processing person-specific information. Inhibition has been proposed to control the activation saliency of one category of person-specific information over other activated categories to guide the processing, interpretation and behavioural responses to socially-relevant stimuli. The current research considers a) whether inhibition operates in a similar manner for both self- and other-referent information, and b) whether the inhibitory mechanism associated with laboratory-observed retrieval-induced forgetting is also involved in categorically thinking about the self and others. Participants studied and carried out guided retrieval practice on positive and negative self- and other-referent traits in seven studies that used variants of the retrieval practice paradigm. The observed patterns of forgetting were found to be consistent with the notion that retrieval inhibition operates in a flexible goal-directed manner to reduce the activation of person-specific information that carries little or no meaning for the social perceiver, regardless of whether that information relates to the self or to a target other. Consideration of the significance subjectively attributed to person information showed that both personally significant self information (Studies 4a,b, 5b) and highly informative other-referent material (Studies 2, 5b) are protected against active forgetting, whilst information of low diagnostic value succumbs to inhibitory processing. The goal-directed nature of active forgetting was also shown to operate in an implicit manner (Study 4a) which remained unaffected by attentional focus being brought to bear on target or non-target items (Study 4b). Two main conclusions are discussed, a) that both self- and other-referent information are protected against active forgetting where that information carries meaning for the social perceiver and becomes integrated into existing person-specific knowledge, and b) that both the retrieval practice procedure and the processes involved in categorical person perception may be subject to the same inhibitory mechanism.Causal information and social learning in chimpanzees (Pan troglodytes) and children (Homo sapiens)Horner, Victoriahttps://hdl.handle.net/10023/131192019-04-01T10:41:17Z2004-01-01T00:00:00ZMany of the tool-using activities of both chimpanzees and children involve a complex mixture of interconnected causal relationships between a tool and a reward, and much of this tool-use is thought to be acquired, at least in part, by social learning. However, despite the considerable research effort focused on both causal understanding and social learning, few studies have directly addressed the potential interaction between these areas. It seems likely that the way in which an individual learns to use a tool through observation will be significantly influenced by its understanding of the causal relationships that it observes. This thesis presents a series of nine experiments with 3- to 7-year-old chimpanzees and 3- 6-year-old children, designed to investigate whether causal information is involved in determining which social learning strategy they employ. The first set of experiments demonstrated that chimpanzees could be influence to switch between imitation and emulation to solve the same task, by altering the availability of causal information. When causal information was available, by presenting a tool-use task in a transparent condition, chimpanzees were found to reproduce only the results of a model's behaviour, consistent with emulation. However, when the availability of causal information was restricted, by presenting the same task in an opaque condition, the chimpanzees included a greater proportion of the model's behaviour, consistent with imitation. The second set of experiments revealed that chimpanzees could learn specific causal information by observation, such as the significance of tool-reward contact. However, they may be overwhelmed by observing multiple causal relationships, or those involving unobservable causal principles, such as gravity or force. The common view that the widespread evidence for emulation in chimpanzee social learning studies indicates a deficit of imitative capacity may therefore be misleading. The results of this thesis suggest more generally that when causal information is available, chimpanzees tend to use emulation. They are also able to imitate, but do so mainly in situations where emulation is not possible. Thus, the availability of causal information plays an important role in chimpanzee social learning, by determining which learning strategy is employed, and ultimately the degree of behavioural fidelity that is achieved, hi contrast, the studies with children revealed that they imitate the actions that they observe without appearing to consider the causal efficiency of their behaviour. This may be due to a greater focus on the actions of a demonstrator rather than the results or goals of their behaviour, and a greater tendency to interpret those actions as intentional.
2004-01-01T00:00:00ZHorner, VictoriaMany of the tool-using activities of both chimpanzees and children involve a complex mixture of interconnected causal relationships between a tool and a reward, and much of this tool-use is thought to be acquired, at least in part, by social learning. However, despite the considerable research effort focused on both causal understanding and social learning, few studies have directly addressed the potential interaction between these areas. It seems likely that the way in which an individual learns to use a tool through observation will be significantly influenced by its understanding of the causal relationships that it observes. This thesis presents a series of nine experiments with 3- to 7-year-old chimpanzees and 3- 6-year-old children, designed to investigate whether causal information is involved in determining which social learning strategy they employ. The first set of experiments demonstrated that chimpanzees could be influence to switch between imitation and emulation to solve the same task, by altering the availability of causal information. When causal information was available, by presenting a tool-use task in a transparent condition, chimpanzees were found to reproduce only the results of a model's behaviour, consistent with emulation. However, when the availability of causal information was restricted, by presenting the same task in an opaque condition, the chimpanzees included a greater proportion of the model's behaviour, consistent with imitation. The second set of experiments revealed that chimpanzees could learn specific causal information by observation, such as the significance of tool-reward contact. However, they may be overwhelmed by observing multiple causal relationships, or those involving unobservable causal principles, such as gravity or force. The common view that the widespread evidence for emulation in chimpanzee social learning studies indicates a deficit of imitative capacity may therefore be misleading. The results of this thesis suggest more generally that when causal information is available, chimpanzees tend to use emulation. They are also able to imitate, but do so mainly in situations where emulation is not possible. Thus, the availability of causal information plays an important role in chimpanzee social learning, by determining which learning strategy is employed, and ultimately the degree of behavioural fidelity that is achieved, hi contrast, the studies with children revealed that they imitate the actions that they observe without appearing to consider the causal efficiency of their behaviour. This may be due to a greater focus on the actions of a demonstrator rather than the results or goals of their behaviour, and a greater tendency to interpret those actions as intentional.No evidence for contagious yawning in lemursReddy, Rachna B.Krupenye, ChristopherMacLean, Evan L.Hare, Brianhttps://hdl.handle.net/10023/130222024-02-17T00:42:21Z2016-09-01T00:00:00ZAmong some haplorhine primates, including humans, relaxed yawns spread contagiously. Such contagious yawning has been linked to social bonds and empathy in some species. However, no studies have investigated contagious yawning in strepsirhines. We conducted an experimental study of contagious yawning in strepsirhines, testing ring-tailed and ruffed lemurs (n = 24) in a paradigm similar to one that has induced contagious yawning in haplorhines. First, in a control experiment, we investigated whether lemurs responded to projected video content in general (experiment 1). We showed them two videos to which we expected differential responses: one featured a terrestrial predator and the other a caretaker holding food. Next, to test for yawn contagion, we showed individual lemurs life-size video projections of groupmates and conspecific strangers yawning, and control footage of the same individuals at rest (experiment 2). Then, to examine whether a group context might enhance or allow for contagion, we exposed subjects to the same videos in a group setting (experiment 3). Lemurs produced alarm vocalizations and moved upward while viewing the predator, but not the caretaker, demonstrating that they do perceive video content meaningfully. However, lemurs did not yawn in response to yawning stimuli when tested alone, or with their groupmates. This study provides preliminary evidence that lemurs do not respond to yawning stimuli similarly to haplorhines, and suggests that this behavior may have evolved or become more exaggerated in haplorhines after the two major primate lineages split.
This research was supported by a Grant from the Undergraduate Research Support office at Duke University and a Molly H. Glander Student Research Grant from the Duke Lemur Center. RBR and CK were supported by NSF GRFP DGE-1256260 and DGE-1106401, respectively.
2016-09-01T00:00:00ZReddy, Rachna B.Krupenye, ChristopherMacLean, Evan L.Hare, BrianAmong some haplorhine primates, including humans, relaxed yawns spread contagiously. Such contagious yawning has been linked to social bonds and empathy in some species. However, no studies have investigated contagious yawning in strepsirhines. We conducted an experimental study of contagious yawning in strepsirhines, testing ring-tailed and ruffed lemurs (n = 24) in a paradigm similar to one that has induced contagious yawning in haplorhines. First, in a control experiment, we investigated whether lemurs responded to projected video content in general (experiment 1). We showed them two videos to which we expected differential responses: one featured a terrestrial predator and the other a caretaker holding food. Next, to test for yawn contagion, we showed individual lemurs life-size video projections of groupmates and conspecific strangers yawning, and control footage of the same individuals at rest (experiment 2). Then, to examine whether a group context might enhance or allow for contagion, we exposed subjects to the same videos in a group setting (experiment 3). Lemurs produced alarm vocalizations and moved upward while viewing the predator, but not the caretaker, demonstrating that they do perceive video content meaningfully. However, lemurs did not yawn in response to yawning stimuli when tested alone, or with their groupmates. This study provides preliminary evidence that lemurs do not respond to yawning stimuli similarly to haplorhines, and suggests that this behavior may have evolved or become more exaggerated in haplorhines after the two major primate lineages split.Sex differences in social learning : exploring the links with risk aversion and confidenceBrand, Charlotte Oliviahttps://hdl.handle.net/10023/130012023-09-04T15:53:41Z2017-06-20T00:00:00ZIn this thesis, I explore sex differences in adult human social learning, and how these sex differences might be underpinned by differences in risk-taking and confidence. The capacity for high-fidelity social learning is fundamental to the complex culture observed in humans. Examining when we choose to learn socially rather than asocially and the factors that influence these choices is valuable for understanding broader patterns of cultural evolution. In Chapter 1, I give an overview of the literature on sex differences in social learning, particularly how individual differences in risk-taking and confidence impact upon social information use. I introduce stereotype threat as a possible factor affecting women’s confidence. I then use the stereotype threat literature as an example of the replication crisis in psychology, and discuss how improved methods of statistical analysis could help to elucidate the ambiguity in this literature. Chapter 2 provides an experimental investigation into when adult humans choose to use social or asocial information to solve a virtual construction task. I found that when the asocial information was made to be risky, women, but not men, preferred to learn socially. In Chapter 3, I present experimental data exploring the links between confidence and conformity. I found that lower confidence led to a greater likelihood of conforming, although I was unable to reliably alter confidence levels experimentally. In Chapter 4, I present a model of the stereotype threat literature by simulating numerous datasets and analysing them using four different statistical methods. I found that using informative priors in a Bayesian framework provided greater certainty about the presence or absence of an effect in a population. Finally, in Chapter 5 I conclude that studying the factors that lead to sex differences in social learning provides researchers with a greater understanding of the dynamics of cultural evolution.
2017-06-20T00:00:00ZBrand, Charlotte OliviaIn this thesis, I explore sex differences in adult human social learning, and how these sex differences might be underpinned by differences in risk-taking and confidence. The capacity for high-fidelity social learning is fundamental to the complex culture observed in humans. Examining when we choose to learn socially rather than asocially and the factors that influence these choices is valuable for understanding broader patterns of cultural evolution. In Chapter 1, I give an overview of the literature on sex differences in social learning, particularly how individual differences in risk-taking and confidence impact upon social information use. I introduce stereotype threat as a possible factor affecting women’s confidence. I then use the stereotype threat literature as an example of the replication crisis in psychology, and discuss how improved methods of statistical analysis could help to elucidate the ambiguity in this literature. Chapter 2 provides an experimental investigation into when adult humans choose to use social or asocial information to solve a virtual construction task. I found that when the asocial information was made to be risky, women, but not men, preferred to learn socially. In Chapter 3, I present experimental data exploring the links between confidence and conformity. I found that lower confidence led to a greater likelihood of conforming, although I was unable to reliably alter confidence levels experimentally. In Chapter 4, I present a model of the stereotype threat literature by simulating numerous datasets and analysing them using four different statistical methods. I found that using informative priors in a Bayesian framework provided greater certainty about the presence or absence of an effect in a population. Finally, in Chapter 5 I conclude that studying the factors that lead to sex differences in social learning provides researchers with a greater understanding of the dynamics of cultural evolution.A comparative study of the understanding of invisible object displacements in macaque monkeys (Macaca mulatta and arctoides) and children (Homo sapiens)Southgate, Victoria H.https://hdl.handle.net/10023/129532019-04-01T10:40:45Z2005-01-01T00:00:00ZThe ability to infer the invisible displacement of objects has long been thought to elude most species with the exception of humans and great apes. However, in recent years, a number of researchers have proposed that this elusive capacity, rather than reflecting profound differences in the conceptual abilities of monkeys and other nonprimates, may instead reflect differences in processing capacities (such as inhibition and working memory). This thesis investigated knowledge of occluded object movements involving gravity, in rhesus and stumptail macaques (Macaca mulatta and arctoides), and two- and three-year-old children (Homo sapiens). In the first part of the thesis, using manual search tasks, a behavioural analysis revealed a number of biases that influence search on invisible displacement tasks, but also showed that contrary to the contentions of some authors, these biases do not mask the existence of correct representations. One study did reveal how seemingly mundane differences between tasks might lead to markedly different patterns of search and emergence of biases. In the second part of the thesis, in the first direct test of the prediction-postdiction hypothesis, an analysis of anticipatory eye gaze suggested that an inability to predict the location of an object does not account for the looking-searching dissociation that has become so prevalent in both the developmental and comparative literature. In attempting to bring together the findings from all the chapters, a framework is suggested in which representations are viewed as differing in strength such that the strength of a representation may determine whether or not a pre-existing bias surfaces in behaviour.
2005-01-01T00:00:00ZSouthgate, Victoria H.The ability to infer the invisible displacement of objects has long been thought to elude most species with the exception of humans and great apes. However, in recent years, a number of researchers have proposed that this elusive capacity, rather than reflecting profound differences in the conceptual abilities of monkeys and other nonprimates, may instead reflect differences in processing capacities (such as inhibition and working memory). This thesis investigated knowledge of occluded object movements involving gravity, in rhesus and stumptail macaques (Macaca mulatta and arctoides), and two- and three-year-old children (Homo sapiens). In the first part of the thesis, using manual search tasks, a behavioural analysis revealed a number of biases that influence search on invisible displacement tasks, but also showed that contrary to the contentions of some authors, these biases do not mask the existence of correct representations. One study did reveal how seemingly mundane differences between tasks might lead to markedly different patterns of search and emergence of biases. In the second part of the thesis, in the first direct test of the prediction-postdiction hypothesis, an analysis of anticipatory eye gaze suggested that an inability to predict the location of an object does not account for the looking-searching dissociation that has become so prevalent in both the developmental and comparative literature. In attempting to bring together the findings from all the chapters, a framework is suggested in which representations are viewed as differing in strength such that the strength of a representation may determine whether or not a pre-existing bias surfaces in behaviour.On social, cultural and cognitive aspects of theory of mind in practiceLoth, Evahttps://hdl.handle.net/10023/129522019-04-01T10:40:58Z2003-01-01T00:00:00ZTheory of mind (ToM) describes the ability to represent internal mental states. We propose that using ToM in practice depends upon the interplay of social, cultural and cognitive factors. The argument is divided into two parts. First, we studied whether people with an Autism Spectrum Disorder (ASD) may have deficits, which impair acquisition of the cultural knowledge necessary to use ToM in practice. The acquisition of shared beliefs, such as social norms, might indirectly rely on metarepresentational capacities. Moreover, a piecemeal processing style - Weak Central Coherence (WCC) - might translate into difficulties in the acquisition of scripts of routine events, which are normally represented as holistic, hierarchically organised knowledge structures. In four experiments we show, first, that WCC may be specific, but not universal to individuals with ASD and that WCC and ToM deficits frequently overlap. Of the ASD group with different levels of ToM abilities, only those with ToM deficits had greater impairments in drawing inferences from social norms than matched control groups. Script abnormalities ranged from a profound lack of event knowledge to more subtle qualitative peculiarities. Especially ASD with WCC and ToM deficits showed a tendency to treat optional and very specific event acts that could occur as should be occurring. The second part of the argument investigated whether power relations affect ToM usage in ordinary adults. A method to track and categorise ToM in ordinary talk was developed to study adults' accounts of real-life experiences in multi-cultural settings. Key findings were that the quality and quantity of ToM talk differed when people accounted for experiences of situated powerlessness (that is, experiences of being discriminated against) compared to when they considered episodes in which power relations were equal. Preliminary data from an experimental study suggests that adults were more inaccurate in inferring the mental states of less powerful as opposed to equally powerful others. We conclude by suggesting that an integrated social, cultural and cognitive framework of ToM in practice may contribute to our understanding of the social phenotype of ASD as well as it provides a new perspective on social phenomena such as intergroup relations.
2003-01-01T00:00:00ZLoth, EvaTheory of mind (ToM) describes the ability to represent internal mental states. We propose that using ToM in practice depends upon the interplay of social, cultural and cognitive factors. The argument is divided into two parts. First, we studied whether people with an Autism Spectrum Disorder (ASD) may have deficits, which impair acquisition of the cultural knowledge necessary to use ToM in practice. The acquisition of shared beliefs, such as social norms, might indirectly rely on metarepresentational capacities. Moreover, a piecemeal processing style - Weak Central Coherence (WCC) - might translate into difficulties in the acquisition of scripts of routine events, which are normally represented as holistic, hierarchically organised knowledge structures. In four experiments we show, first, that WCC may be specific, but not universal to individuals with ASD and that WCC and ToM deficits frequently overlap. Of the ASD group with different levels of ToM abilities, only those with ToM deficits had greater impairments in drawing inferences from social norms than matched control groups. Script abnormalities ranged from a profound lack of event knowledge to more subtle qualitative peculiarities. Especially ASD with WCC and ToM deficits showed a tendency to treat optional and very specific event acts that could occur as should be occurring. The second part of the argument investigated whether power relations affect ToM usage in ordinary adults. A method to track and categorise ToM in ordinary talk was developed to study adults' accounts of real-life experiences in multi-cultural settings. Key findings were that the quality and quantity of ToM talk differed when people accounted for experiences of situated powerlessness (that is, experiences of being discriminated against) compared to when they considered episodes in which power relations were equal. Preliminary data from an experimental study suggests that adults were more inaccurate in inferring the mental states of less powerful as opposed to equally powerful others. We conclude by suggesting that an integrated social, cultural and cognitive framework of ToM in practice may contribute to our understanding of the social phenotype of ASD as well as it provides a new perspective on social phenomena such as intergroup relations.Enforced change at work, the reconstruction of basic assumptions and its influence on attribution, self-sufficiency and the psychological contractRandall, Julianhttps://hdl.handle.net/10023/128992019-04-01T10:40:05Z2001-01-01T00:00:00ZThe theoretical underpinning of Human Resource Management assumes the existence of individual motivation, which can be manipulated or managed in a way that enables organisational objectives to be achieved with the compliance and commitment of the individual worker. However, the increasing incidence of mergers, takeovers and reengineering has imposed on the individuals caught up in it change and challenge, which leaves even those retaining their employment doubtful of the benefits of HRM proclaimed by employers. Job insecurity has been well researched by those who wish to examine how enforced change affects the survivors both within the organisation and those who move on to alternative employment elsewhere. Charting the change undergone by individuals suffering such enforced change at work has traditionally involved attempts to measure the antecedents of change and correlating it to the consequences of the change. In this way the effects of imposed change on individuals can be linked to organisational consequences like intention to leave or job satisfaction. The present research allows individuals to reflect on their own confirmed and disconfirmed expectancies following the experience of enforced change at work. It allows them to examine what assumptions they had about their employer's behaviour during enforced change and how far they have accepted or rejected the legitimacy of that behaviour. For each of them this has involved interpreting events occurring during enforced change. Such interpretation may reinforce the meaning of work and its inherent value or threaten continued belief in the value of employers' promises of employment and career development. Identifying expectancies enables the researcher to examine the different responses to questions of attribution, self-sufficiency and the traditional elements of loyalty and trust together with the individual's assessment of how he or she would respond to a repeat of such enforced change. The conclusions of the present research indicate that individuals who maintain traditional beliefs of loyalty and trust are more likely to experience alienation than those who evince an independence who seek to use working experience to gain more knowledge and skill and so increase their own employability. The future dependence of employers on traditional promises of career development and life long learning would seem to have been circumscribed by the many individuals whose experience of enforced change has convinced them they need to take ownership of their own destiny in which different employers will play but a fleeting part.
2001-01-01T00:00:00ZRandall, JulianThe theoretical underpinning of Human Resource Management assumes the existence of individual motivation, which can be manipulated or managed in a way that enables organisational objectives to be achieved with the compliance and commitment of the individual worker. However, the increasing incidence of mergers, takeovers and reengineering has imposed on the individuals caught up in it change and challenge, which leaves even those retaining their employment doubtful of the benefits of HRM proclaimed by employers. Job insecurity has been well researched by those who wish to examine how enforced change affects the survivors both within the organisation and those who move on to alternative employment elsewhere. Charting the change undergone by individuals suffering such enforced change at work has traditionally involved attempts to measure the antecedents of change and correlating it to the consequences of the change. In this way the effects of imposed change on individuals can be linked to organisational consequences like intention to leave or job satisfaction. The present research allows individuals to reflect on their own confirmed and disconfirmed expectancies following the experience of enforced change at work. It allows them to examine what assumptions they had about their employer's behaviour during enforced change and how far they have accepted or rejected the legitimacy of that behaviour. For each of them this has involved interpreting events occurring during enforced change. Such interpretation may reinforce the meaning of work and its inherent value or threaten continued belief in the value of employers' promises of employment and career development. Identifying expectancies enables the researcher to examine the different responses to questions of attribution, self-sufficiency and the traditional elements of loyalty and trust together with the individual's assessment of how he or she would respond to a repeat of such enforced change. The conclusions of the present research indicate that individuals who maintain traditional beliefs of loyalty and trust are more likely to experience alienation than those who evince an independence who seek to use working experience to gain more knowledge and skill and so increase their own employability. The future dependence of employers on traditional promises of career development and life long learning would seem to have been circumscribed by the many individuals whose experience of enforced change has convinced them they need to take ownership of their own destiny in which different employers will play but a fleeting part.Investigating the pathophysiology of Amyotrophic Lateral Sclerosis using human induced pluripotent stem cell technologyDevlin, Anna-Clairehttps://hdl.handle.net/10023/128672023-04-25T11:19:12Z2016-06-01T00:00:00ZAmyotrophic Lateral Sclerosis (ALS) is a devastating, adult onset, neurodegenerative
disease which remains largely untreatable and incurable, reflecting an incomplete
understanding of the key pathogenic mechanisms that underlie motoneuron (MN) loss
in the disease. Through the use of induced pluripotent stem cell (iPSCs) technology,
cells from the human central nervous system can be studied at a range of time points,
including those prior to overt pathology, in order to understand early causative events
in ALS. In the present study, human iPSC-derived MNs and astrocytes were used to
study the pathophysiology of ALS. Whole-cell patch clamp recording techniques
were utilised to investigate whether the functional properties of human iPSC-derived
MNs are altered in cells derived from ALS patients compared to those from healthy
controls. Patient iPSC-derived MNs harbouring C9ORF72 or TARDBP mutations
display an initial period of hyperexcitability followed by a progressive loss of action
potential output due to decreases in voltage-activated Na+ and K+ currents. These
changes occur in the absence of changes in cell viability. Given evidence in support of
non-cell autonomous disease mechanisms in ALS, the potential involvement of
interactions between neurons and astrocytes in the pathophysiological phenotype were
next investigated. Patient iPSC-derived astrocytes harbouring C9ORF72 or TARDBP
G298S mutations cause a loss of functional output in control iPSC-derived MNs, due
to a progressive decrease in voltage-activated Na+ and K+ currents. These data show
that patient iPSC-derived astrocytes can induce pathophysiological changes in control
human iPSC-derived MNs which are similar to those revealed in patient iPSC-derived
MNs. This study also utilizes pharmacological agents and genetic editing to
demonstrate that the pathophysiological phenotype can be altered. Overall, this study implicates MN dysfunction, potentially due to non-cell autonomous disease
mechanisms, as an early contributor to downstream degenerative pathways that
ultimately lead to MN loss in ALS.
2016-06-01T00:00:00ZDevlin, Anna-ClaireAmyotrophic Lateral Sclerosis (ALS) is a devastating, adult onset, neurodegenerative
disease which remains largely untreatable and incurable, reflecting an incomplete
understanding of the key pathogenic mechanisms that underlie motoneuron (MN) loss
in the disease. Through the use of induced pluripotent stem cell (iPSCs) technology,
cells from the human central nervous system can be studied at a range of time points,
including those prior to overt pathology, in order to understand early causative events
in ALS. In the present study, human iPSC-derived MNs and astrocytes were used to
study the pathophysiology of ALS. Whole-cell patch clamp recording techniques
were utilised to investigate whether the functional properties of human iPSC-derived
MNs are altered in cells derived from ALS patients compared to those from healthy
controls. Patient iPSC-derived MNs harbouring C9ORF72 or TARDBP mutations
display an initial period of hyperexcitability followed by a progressive loss of action
potential output due to decreases in voltage-activated Na+ and K+ currents. These
changes occur in the absence of changes in cell viability. Given evidence in support of
non-cell autonomous disease mechanisms in ALS, the potential involvement of
interactions between neurons and astrocytes in the pathophysiological phenotype were
next investigated. Patient iPSC-derived astrocytes harbouring C9ORF72 or TARDBP
G298S mutations cause a loss of functional output in control iPSC-derived MNs, due
to a progressive decrease in voltage-activated Na+ and K+ currents. These data show
that patient iPSC-derived astrocytes can induce pathophysiological changes in control
human iPSC-derived MNs which are similar to those revealed in patient iPSC-derived
MNs. This study also utilizes pharmacological agents and genetic editing to
demonstrate that the pathophysiological phenotype can be altered. Overall, this study implicates MN dysfunction, potentially due to non-cell autonomous disease
mechanisms, as an early contributor to downstream degenerative pathways that
ultimately lead to MN loss in ALS.At face value : how internet access, pubertal timing, environmental harshness, and population familiarity influence facial preferencesBatres, Julia Carlotahttps://hdl.handle.net/10023/128492019-04-01T10:40:51Z2016-04-12T00:00:00ZChapter One introduces the field of evolutionary psychology as well as provides a
review of factors influencing facial attractiveness. Chapter Two presents empirical evidence
that online studies may provide a distorted perspective on cross-cultural face preferences
since online samples are not representative of the populations in developing countries. In El
Salvador, participants without internet access preferred more feminine men as well as heavier
and more masculine women when compared to participants with internet access. One
possible explanation for such findings is that the level of harshness in the environment may
be influencing preferences. One individual difference that is influenced by environmental
harshness is age of menarche. Chapter Three thus provides exploratory evidence that age of
menarche also influences masculinity preferences.
Chapter Four further examines this environmental harshness hypothesis by repeatedly
testing students undergoing intensive training at an army camp. Increases in the harshness of
the environment led to an increased male attraction to cues of higher weight in female faces.
Such changes in preferences may be adaptive because they allow for more opportunities to
form partnerships with individuals who are better equipped to survive.
An alternative explanation for the empirical findings in Chapters Two and Four is that
familiarity may also influence preferences. Chapter Five tests this familiarity hypothesis by
examining the faces of participants in different areas of El Salvador and Malaysia. Rural
participants preferred heavier female faces than urban participants. Additionally, the faces of
female participants from rural areas were rated as looking heavier. This finding suggests that
familiarity may indeed influence attractiveness perceptions. Lastly, Chapter Six draws
conclusions from the empirical findings reported in Chapters Two-Five and lists proposals of
future research that could further enhance our understanding of what we find attractive.
2016-04-12T00:00:00ZBatres, Julia CarlotaChapter One introduces the field of evolutionary psychology as well as provides a
review of factors influencing facial attractiveness. Chapter Two presents empirical evidence
that online studies may provide a distorted perspective on cross-cultural face preferences
since online samples are not representative of the populations in developing countries. In El
Salvador, participants without internet access preferred more feminine men as well as heavier
and more masculine women when compared to participants with internet access. One
possible explanation for such findings is that the level of harshness in the environment may
be influencing preferences. One individual difference that is influenced by environmental
harshness is age of menarche. Chapter Three thus provides exploratory evidence that age of
menarche also influences masculinity preferences.
Chapter Four further examines this environmental harshness hypothesis by repeatedly
testing students undergoing intensive training at an army camp. Increases in the harshness of
the environment led to an increased male attraction to cues of higher weight in female faces.
Such changes in preferences may be adaptive because they allow for more opportunities to
form partnerships with individuals who are better equipped to survive.
An alternative explanation for the empirical findings in Chapters Two and Four is that
familiarity may also influence preferences. Chapter Five tests this familiarity hypothesis by
examining the faces of participants in different areas of El Salvador and Malaysia. Rural
participants preferred heavier female faces than urban participants. Additionally, the faces of
female participants from rural areas were rated as looking heavier. This finding suggests that
familiarity may indeed influence attractiveness perceptions. Lastly, Chapter Six draws
conclusions from the empirical findings reported in Chapters Two-Five and lists proposals of
future research that could further enhance our understanding of what we find attractive.Factors shaping social learning in chimpanzeesWatson, Stuart Kylehttps://hdl.handle.net/10023/127812021-04-07T10:38:40Z2018-06-29T00:00:00ZCulture is an important means by which both human and non-human animals transmit useful behaviours between individuals and generations. Amongst animals, chimpanzees live particularly varied cultural lives. However, the processes and factors that influence whether chimpanzees will be motivated to copy an observed behaviour are poorly understood. In this thesis, I explore various factors and their influence on social learning decisions in chimpanzees. In turn, the chapters examine the influence of (i) rank-bias towards copying dominant individuals, (ii) majority and contextual influences and finally (iii) individual differences in proclivity for social learning. In my first experiment, I found evidence that chimpanzees are highly motivated to copy the behaviour of subordinate demonstrators and innovators in an open-diffusion puzzle-box paradigm. In contrast, behaviours seeded by dominant individuals were not transmitted as faithfully. This finding has important implications for our understanding of the emergence of novel traditions. In my second experiment, I found that some chimpanzees are highly motivated to relinquish an existing behaviour to adopt an equally rewarding alternative if it is consistently demonstrated by just one or two individuals within a group context, but not in a dyadic context. This contrasts with prior studies which argue that chimpanzees are highly conservative and may hint at a hitherto unrecognised process by which conformity-like behaviour might occur. Finally, I performed a novel type of ‘meta’ analysis on 16 social learning studies carried out at our research site to determine whether individuals demonstrated consistency in their social learning behaviour across experimental contexts. Strong evidence for individual differences in social information use was found, with females more likely to use social information than males. No effect of age, research experience or rearing history was found. This presents a promising new method of studying individual differences in behaviour using the accumulated findings of previous work at a study site.
2018-06-29T00:00:00ZWatson, Stuart KyleCulture is an important means by which both human and non-human animals transmit useful behaviours between individuals and generations. Amongst animals, chimpanzees live particularly varied cultural lives. However, the processes and factors that influence whether chimpanzees will be motivated to copy an observed behaviour are poorly understood. In this thesis, I explore various factors and their influence on social learning decisions in chimpanzees. In turn, the chapters examine the influence of (i) rank-bias towards copying dominant individuals, (ii) majority and contextual influences and finally (iii) individual differences in proclivity for social learning. In my first experiment, I found evidence that chimpanzees are highly motivated to copy the behaviour of subordinate demonstrators and innovators in an open-diffusion puzzle-box paradigm. In contrast, behaviours seeded by dominant individuals were not transmitted as faithfully. This finding has important implications for our understanding of the emergence of novel traditions. In my second experiment, I found that some chimpanzees are highly motivated to relinquish an existing behaviour to adopt an equally rewarding alternative if it is consistently demonstrated by just one or two individuals within a group context, but not in a dyadic context. This contrasts with prior studies which argue that chimpanzees are highly conservative and may hint at a hitherto unrecognised process by which conformity-like behaviour might occur. Finally, I performed a novel type of ‘meta’ analysis on 16 social learning studies carried out at our research site to determine whether individuals demonstrated consistency in their social learning behaviour across experimental contexts. Strong evidence for individual differences in social information use was found, with females more likely to use social information than males. No effect of age, research experience or rearing history was found. This presents a promising new method of studying individual differences in behaviour using the accumulated findings of previous work at a study site.Behavioral, ecological, and evolutionary aspects of meat-eating by Sumatran orangutans (Pongo abelii)Hardus, Madeleine E.Lameira, Adriano R.Zulfa, AstriAtmoko, S. Suci Utamide Vries, HanWich, Serge A.https://hdl.handle.net/10023/124552022-04-20T15:50:31Z2012-04-01T00:00:00ZMeat-eating is an important aspect of human evolution, but how meat became a substantial component of the human diet is still poorly understood. Meat-eating in our closest relatives, the great apes, may provide insight into the emergence of this trait, but most existing data are for chimpanzees. We report 3 rare cases of meat-eating of slow lorises, Nycticebus coucang, by 1 Sumatran orangutan mother-infant dyad in Ketambe, Indonesia, to examine how orangutans find slow lorises and share meat. We combine these 3 cases with 2 previous ones to test the hypothesis that slow loris captures by orangutans are seasonal and dependent on fruit availability. We also provide the first (to our knowledge) quantitative data and high-definition video recordings of meat chewing rates by great apes, which we use to estimate the minimum time necessary for a female Australopithecus africanus to reach its daily energy requirements when feeding partially on raw meat. Captures seemed to be opportunistic but orangutans may have used olfactory cues to detect the prey. The mother often rejected meat sharing requests and only the infant initiated meat sharing. Slow loris captures occurred only during low ripe fruit availability, suggesting that meat may represent a filler fallback food for orangutans. Orangutans ate meat more than twice as slowly as chimpanzees (Pan troglodytes), suggesting that group living may function as a meat intake accelerator in hominoids. Using orangutan data as a model, time spent chewing per day would not require an excessive amount of time for our social ancestors (australopithecines and hominids), as long as meat represented no more than a quarter of their diet.
2012-04-01T00:00:00ZHardus, Madeleine E.Lameira, Adriano R.Zulfa, AstriAtmoko, S. Suci Utamide Vries, HanWich, Serge A.Meat-eating is an important aspect of human evolution, but how meat became a substantial component of the human diet is still poorly understood. Meat-eating in our closest relatives, the great apes, may provide insight into the emergence of this trait, but most existing data are for chimpanzees. We report 3 rare cases of meat-eating of slow lorises, Nycticebus coucang, by 1 Sumatran orangutan mother-infant dyad in Ketambe, Indonesia, to examine how orangutans find slow lorises and share meat. We combine these 3 cases with 2 previous ones to test the hypothesis that slow loris captures by orangutans are seasonal and dependent on fruit availability. We also provide the first (to our knowledge) quantitative data and high-definition video recordings of meat chewing rates by great apes, which we use to estimate the minimum time necessary for a female Australopithecus africanus to reach its daily energy requirements when feeding partially on raw meat. Captures seemed to be opportunistic but orangutans may have used olfactory cues to detect the prey. The mother often rejected meat sharing requests and only the infant initiated meat sharing. Slow loris captures occurred only during low ripe fruit availability, suggesting that meat may represent a filler fallback food for orangutans. Orangutans ate meat more than twice as slowly as chimpanzees (Pan troglodytes), suggesting that group living may function as a meat intake accelerator in hominoids. Using orangutan data as a model, time spent chewing per day would not require an excessive amount of time for our social ancestors (australopithecines and hominids), as long as meat represented no more than a quarter of their diet.An investigation of biases in social learning and social attention in wild vervet monkeys (Chlorocebus aethiops pygerythrus) and captive tufted capuchins (Sapajus apella)Botting, Jennifer Lynettehttps://hdl.handle.net/10023/122602021-09-24T02:07:45Z2017-06-20T00:00:00ZResearchers in the field of social learning have suggested that certain biases may exist in whom animals learn from, creating a non-random flow of social information. A number of potential biases have been proposed based upon theoretical models, including biases to copy more dominant individuals or individuals who receive the best payoff from their behaviour, but empirical evidence for these biases is lacking. This thesis presents the first examination of dominance-based bias in a wild population of primates and of a payoff-based bias in captive capuchins.
In two field experiments, dominant and low-ranking females from each of three wild groups of vervet monkeys (Chlorocebus aethiops pygerythrus) in KwaZulu-Natal, South Africa were trained to demonstrate contrasting behaviours to their group before observers were provided with a choice between the two modelled preferences. No evidence was found for a consistent bias to copy the behaviour of the dominant female in either experiment. Instead, in both experiments, a preference for one behaviour emerged, regardless of model rank. In the latter experiment, higher-ranking females were significantly more likely to match the dominant model’s action than were low-ranking females. The low-ranking models were more likely than their high-ranking counterparts to switch behaviours, despite their trained behaviour continuing to be productive. An analyses of the observations revealed that observers were biased towards attending to kin, and observer age appeared to influence access to the dominant models, but no overall preference to attend to the dominant female was found. Together these findings indicate that kinship, sex, age and preferences for specific behaviours are more important factors than model rank in vervet monkey social learning.
Finally, I examined whether captive tufted capuchins (Sapajus apella) utilized a payoff-based social learning bias in their foraging decisions. Subjects did not utilize public information when choosing between demonstrated resource-rich and resource-poor sites, suggesting that the social learning abilities of capuchins may not extend to determining the profitability of feeding sites, although limitations of the study are discussed.
2017-06-20T00:00:00ZBotting, Jennifer LynetteResearchers in the field of social learning have suggested that certain biases may exist in whom animals learn from, creating a non-random flow of social information. A number of potential biases have been proposed based upon theoretical models, including biases to copy more dominant individuals or individuals who receive the best payoff from their behaviour, but empirical evidence for these biases is lacking. This thesis presents the first examination of dominance-based bias in a wild population of primates and of a payoff-based bias in captive capuchins.
In two field experiments, dominant and low-ranking females from each of three wild groups of vervet monkeys (Chlorocebus aethiops pygerythrus) in KwaZulu-Natal, South Africa were trained to demonstrate contrasting behaviours to their group before observers were provided with a choice between the two modelled preferences. No evidence was found for a consistent bias to copy the behaviour of the dominant female in either experiment. Instead, in both experiments, a preference for one behaviour emerged, regardless of model rank. In the latter experiment, higher-ranking females were significantly more likely to match the dominant model’s action than were low-ranking females. The low-ranking models were more likely than their high-ranking counterparts to switch behaviours, despite their trained behaviour continuing to be productive. An analyses of the observations revealed that observers were biased towards attending to kin, and observer age appeared to influence access to the dominant models, but no overall preference to attend to the dominant female was found. Together these findings indicate that kinship, sex, age and preferences for specific behaviours are more important factors than model rank in vervet monkey social learning.
Finally, I examined whether captive tufted capuchins (Sapajus apella) utilized a payoff-based social learning bias in their foraging decisions. Subjects did not utilize public information when choosing between demonstrated resource-rich and resource-poor sites, suggesting that the social learning abilities of capuchins may not extend to determining the profitability of feeding sites, although limitations of the study are discussed. Adolescent stress and social experiences : developmental antecedents of adult behavioural responses to unfamiliar stimuli and the underlying neuroendocrine mechanismsEmmerson, Michael Georgehttps://hdl.handle.net/10023/120942022-08-29T13:48:20Z2017-12-07T00:00:00ZDuring adolescence, animals leave the natal home and interact with potentially threatening stimuli (i.e. stressors), e.g. unfamiliar environments and conspecifics. Adolescent stressors can result in fewer interactions with unfamiliar stimuli in adulthood, plausibly due to sustained effects of glucocorticoid exposure on stress physiology (e.g. glucocorticoid secretion and receptor expression). The current thesis tested the hypothesis that adolescent glucocorticoid exposure and social experiences act as stressors by quantifying the effects of the adolescent experiences on behavioural responses to unfamiliar stimuli and the underlying neuroendocrine mechanisms when in adulthood using two captive species, zebra finches and rats. In study one, adolescent zebra finches were dosed with the glucocorticoid corticosterone. In adulthood, birds dosed with corticosterone in early adolescence took longer to enter an unfamiliar environment when tested individually and had lower expression of the glucocorticoid receptor GR in the hippocampus and hypothalamus, brain regions that regulate stress responses. Glucocorticoids therefore appear to be an endocrine mechanism behind the long-term effects of adolescent stress. Subsequent studies explored whether higher social density and more unfamiliar social interactions during adolescence act as stressors. In study two, early adolescent zebra finches were housed in groups varying in conspecific number and density. In adulthood, females raised in larger groups secreted a higher stressor-induced corticosterone concentration and, if raised at lower density, spent more time in an unfamiliar environment when group housed. In study
three, adolescent female rats were housed in familiar pairs or exposed to unfamiliar conspecifics. Unfamiliar adolescent interactions had no effects on responses to unfamiliar environments or stress physiology in adulthood, but heightened ultrasonic call rates. In this thesis, adolescent social experiences do not act like stressors, but modulate (especially female)
social behaviour. Adolescent stressors and social experiences therefore have distinct effects on responses to unfamiliar stimuli and stress physiology that are maintained into adulthood.
2017-12-07T00:00:00ZEmmerson, Michael GeorgeDuring adolescence, animals leave the natal home and interact with potentially threatening stimuli (i.e. stressors), e.g. unfamiliar environments and conspecifics. Adolescent stressors can result in fewer interactions with unfamiliar stimuli in adulthood, plausibly due to sustained effects of glucocorticoid exposure on stress physiology (e.g. glucocorticoid secretion and receptor expression). The current thesis tested the hypothesis that adolescent glucocorticoid exposure and social experiences act as stressors by quantifying the effects of the adolescent experiences on behavioural responses to unfamiliar stimuli and the underlying neuroendocrine mechanisms when in adulthood using two captive species, zebra finches and rats. In study one, adolescent zebra finches were dosed with the glucocorticoid corticosterone. In adulthood, birds dosed with corticosterone in early adolescence took longer to enter an unfamiliar environment when tested individually and had lower expression of the glucocorticoid receptor GR in the hippocampus and hypothalamus, brain regions that regulate stress responses. Glucocorticoids therefore appear to be an endocrine mechanism behind the long-term effects of adolescent stress. Subsequent studies explored whether higher social density and more unfamiliar social interactions during adolescence act as stressors. In study two, early adolescent zebra finches were housed in groups varying in conspecific number and density. In adulthood, females raised in larger groups secreted a higher stressor-induced corticosterone concentration and, if raised at lower density, spent more time in an unfamiliar environment when group housed. In study
three, adolescent female rats were housed in familiar pairs or exposed to unfamiliar conspecifics. Unfamiliar adolescent interactions had no effects on responses to unfamiliar environments or stress physiology in adulthood, but heightened ultrasonic call rates. In this thesis, adolescent social experiences do not act like stressors, but modulate (especially female)
social behaviour. Adolescent stressors and social experiences therefore have distinct effects on responses to unfamiliar stimuli and stress physiology that are maintained into adulthood.Interactions via electrical coupling in axial and appendicular motor networks during metamorphosis in Xenopus laevis tadpolesWagner, Monica Annehttps://hdl.handle.net/10023/120102019-04-01T10:40:14Z2017-06-20T00:00:00ZThe spinal locomotor networks in Xenopus laevis frog tadpoles undergo a remarkable transformation during metamorphosis to accommodate a switch from axial-based swimming to a limb-based kicking locomotor strategy. For a brief period during ontogeny, both the axial- and limb-based systems are present and functional, but reliant on different central pattern generators (CPGs) that are simultaneously active. However, the mechanisms controlling the functional coupling both within and between these locomotor networks are unknown. At metamorphosing larval stages (52-58), retrograde motoneuron (MN) backfilling from both axial (11th-12th post-otic segments) and hindlimb muscles with fluorescent rhodamine- and fluorescein-conjugated dextran dyes revealed two discrete MN populations (axial and appendicular) within the spinal cord. The co-labelling of both axial and appendicular cells provides evidence that the two MN pools in the lumbar enlargement are coupled. Electrophysiological data from animals at the same larval stages suggest that axial CPG excitability is modified as burst durations were increased by gap junction (GJ) blockers (18-β-glycyrrhetinic (18-β-GA) acid 100µM; CBNX 200µM), however, limb CPG burst parameters were not altered by GJ block. For spontaneous fictive locomotor bouts, the number of axial episodes initially increased, but then sharply decreased from control levels ~15-30 minutes after drug application. Coordinated and simultaneous axial and limb CPG output was observed with electrical stimulation to the optic tectum, an axial ventral root (VR), and a limb VR; GJ block did not affect the coordinated output from optic tectum stimulation, however, it decreased simultaneous output when the axial VR was stimulated. This novel finding that antidromic stimulation of an axial VR is sufficient to activate a different CPG for the limbs suggests there is synaptic coupling in the direction of axial to limb. These data suggest that axial CPG output is in part regulated by GJs. The anatomical data also suggest a connection exists between the axial and limb MN pools, and may be involved in the initial cycle-by-cycle coupling of the two CPG outputs. Thus the rhythm of the appendicular CPG is initially highly dependent on that of the axial CPG, which in turn is dependent on its own GJ connections within the spinal circuit. It appears that the immature limb MN pools in the lumbar spinal cord possess functional connections via electrical synapses to the axial locomotor system, which are presumably “pruned” as metamorphosis proceeds, and eventually lost completely by the adult stages when the limb network has become completely independent.
2017-06-20T00:00:00ZWagner, Monica AnneThe spinal locomotor networks in Xenopus laevis frog tadpoles undergo a remarkable transformation during metamorphosis to accommodate a switch from axial-based swimming to a limb-based kicking locomotor strategy. For a brief period during ontogeny, both the axial- and limb-based systems are present and functional, but reliant on different central pattern generators (CPGs) that are simultaneously active. However, the mechanisms controlling the functional coupling both within and between these locomotor networks are unknown. At metamorphosing larval stages (52-58), retrograde motoneuron (MN) backfilling from both axial (11th-12th post-otic segments) and hindlimb muscles with fluorescent rhodamine- and fluorescein-conjugated dextran dyes revealed two discrete MN populations (axial and appendicular) within the spinal cord. The co-labelling of both axial and appendicular cells provides evidence that the two MN pools in the lumbar enlargement are coupled. Electrophysiological data from animals at the same larval stages suggest that axial CPG excitability is modified as burst durations were increased by gap junction (GJ) blockers (18-β-glycyrrhetinic (18-β-GA) acid 100µM; CBNX 200µM), however, limb CPG burst parameters were not altered by GJ block. For spontaneous fictive locomotor bouts, the number of axial episodes initially increased, but then sharply decreased from control levels ~15-30 minutes after drug application. Coordinated and simultaneous axial and limb CPG output was observed with electrical stimulation to the optic tectum, an axial ventral root (VR), and a limb VR; GJ block did not affect the coordinated output from optic tectum stimulation, however, it decreased simultaneous output when the axial VR was stimulated. This novel finding that antidromic stimulation of an axial VR is sufficient to activate a different CPG for the limbs suggests there is synaptic coupling in the direction of axial to limb. These data suggest that axial CPG output is in part regulated by GJs. The anatomical data also suggest a connection exists between the axial and limb MN pools, and may be involved in the initial cycle-by-cycle coupling of the two CPG outputs. Thus the rhythm of the appendicular CPG is initially highly dependent on that of the axial CPG, which in turn is dependent on its own GJ connections within the spinal circuit. It appears that the immature limb MN pools in the lumbar spinal cord possess functional connections via electrical synapses to the axial locomotor system, which are presumably “pruned” as metamorphosis proceeds, and eventually lost completely by the adult stages when the limb network has become completely independent.From self to social cognition : a new paradigm to study differentiations within the Theory of Mind mechanism and their relation to executive functioningBradford, Elisabeth E. F.https://hdl.handle.net/10023/120052018-03-08T16:14:27Z2016-06-21T00:00:00ZTheory of Mind (ToM) refers to the ability to attribute mental states to oneself and other people. In this thesis, I present a new paradigm, the Self/Other Differentiation task, which was designed to assess ToM abilities – specifically, the ability to attribute belief states to the ‘Self’ and ‘Other’ – in typically developed, healthy adults. By focussing on fully developed ToM abilities, we aimed to increase understanding of how the ToM mechanism is structured and functions in everyday life, and how individual ToM components may differentially relate to executive functioning (EF) abilities. The Self/Other Differentiation task is a computerized false-belief task utilizing a matched- design to allow direct comparison of self-oriented versus other-oriented belief- attribution processes. Using behavioural (response times/error rates) and electrophysiological (EEG) methods, the work presented in this thesis provides evidence of a clear and distinct differentiation in the processing of ‘Self’ versus ‘Other’ perspectives in healthy ToM. We established a key role of perspective-shifting in ToM, which we hypothesize plays a crucial role in day-to-day communications; shifting from the Self-to-Other perspective was significantly harder (longer and more error prone) than shifting from the Other-to-Self perspective, suggesting that the ‘Self’ forms the stem of understanding the ‘Other’. EEG analysis revealed these effects were present across fronto-lateral and occipital-lateral areas of the brain, particularly across the right hemisphere in parietal regions. We provide evidence of these features as universal, core components of the ToM mechanism, with data collected from both Chinese and Western cultures illustrating similar patterns of results. Results regarding the relationship between ToM and EF were mixed, with one study finding that affective EF positively correlates with ToM task performance, whilst non-affective EF does not, and a further two studies finding no such differential relationship. The Self/Other Differentiation task provides the opportunity to establish the features of ‘typical’ ToM processes in healthy adults, to further our understanding of how the mature ToM mechanism functions.
2016-06-21T00:00:00ZBradford, Elisabeth E. F.Theory of Mind (ToM) refers to the ability to attribute mental states to oneself and other people. In this thesis, I present a new paradigm, the Self/Other Differentiation task, which was designed to assess ToM abilities – specifically, the ability to attribute belief states to the ‘Self’ and ‘Other’ – in typically developed, healthy adults. By focussing on fully developed ToM abilities, we aimed to increase understanding of how the ToM mechanism is structured and functions in everyday life, and how individual ToM components may differentially relate to executive functioning (EF) abilities. The Self/Other Differentiation task is a computerized false-belief task utilizing a matched- design to allow direct comparison of self-oriented versus other-oriented belief- attribution processes. Using behavioural (response times/error rates) and electrophysiological (EEG) methods, the work presented in this thesis provides evidence of a clear and distinct differentiation in the processing of ‘Self’ versus ‘Other’ perspectives in healthy ToM. We established a key role of perspective-shifting in ToM, which we hypothesize plays a crucial role in day-to-day communications; shifting from the Self-to-Other perspective was significantly harder (longer and more error prone) than shifting from the Other-to-Self perspective, suggesting that the ‘Self’ forms the stem of understanding the ‘Other’. EEG analysis revealed these effects were present across fronto-lateral and occipital-lateral areas of the brain, particularly across the right hemisphere in parietal regions. We provide evidence of these features as universal, core components of the ToM mechanism, with data collected from both Chinese and Western cultures illustrating similar patterns of results. Results regarding the relationship between ToM and EF were mixed, with one study finding that affective EF positively correlates with ToM task performance, whilst non-affective EF does not, and a further two studies finding no such differential relationship. The Self/Other Differentiation task provides the opportunity to establish the features of ‘typical’ ToM processes in healthy adults, to further our understanding of how the mature ToM mechanism functions.Linking 3D face shape to social perceptionHolzleitner, Iris J.https://hdl.handle.net/10023/119702019-04-01T10:41:41Z2015-09-01T00:00:00ZAdvances in computer graphic and statistical methods have made it possible to visualise global face shape correlates of social judgments. The current thesis used a data-driven approach to investigate face shape correlates and perception of two traits, masculinity and strength, both of which are important in mate choice and social perception more generally. The studies presented defined the influences of body physique (height, body mass index, body fat and muscle mass) on facial shape, and their effects on the perception of masculinity, attractiveness and strength. Study 1 investigated the face shape correlates of actual and perceived masculinity. I found that perceived masculinity is not only driven by sexually dimorphic shape, but also by cues to body height and weight. Men with taller and heavier bodies were perceived to have more masculine-looking faces.
Study 2 investigated women’s perception of male attractiveness as a function of masculine face shape. As previously assumed but not explicitly tested, I found that masculinity preferences followed a quadratic relationship: attractiveness increased with increasing masculinity levels, but dropped o. at higher levels of masculinity. In addition, I showed that the relative costs and benefits of high and low masculinity are affected by individual differences in own condition, perceived financial harshness and pathogen disgust.
In Study 3, I found that perception of strength from faces is driven by facial cues to body physique; individuals with higher body bulk were perceived to be stronger. In men, it proved possible to further dissociate facial cues to muscle and fat mass which both contributed to strength perception. The thesis demonstrates that facial cues used in the evaluation of masculinity and strength are linked to bodily characteristics associated with sex differences and actual strength, namely height, weight, muscularity and adiposity. My findings therefore support the hypothesis that perceptions have an adaptive origin.
2015-09-01T00:00:00ZHolzleitner, Iris J.Advances in computer graphic and statistical methods have made it possible to visualise global face shape correlates of social judgments. The current thesis used a data-driven approach to investigate face shape correlates and perception of two traits, masculinity and strength, both of which are important in mate choice and social perception more generally. The studies presented defined the influences of body physique (height, body mass index, body fat and muscle mass) on facial shape, and their effects on the perception of masculinity, attractiveness and strength. Study 1 investigated the face shape correlates of actual and perceived masculinity. I found that perceived masculinity is not only driven by sexually dimorphic shape, but also by cues to body height and weight. Men with taller and heavier bodies were perceived to have more masculine-looking faces.
Study 2 investigated women’s perception of male attractiveness as a function of masculine face shape. As previously assumed but not explicitly tested, I found that masculinity preferences followed a quadratic relationship: attractiveness increased with increasing masculinity levels, but dropped o. at higher levels of masculinity. In addition, I showed that the relative costs and benefits of high and low masculinity are affected by individual differences in own condition, perceived financial harshness and pathogen disgust.
In Study 3, I found that perception of strength from faces is driven by facial cues to body physique; individuals with higher body bulk were perceived to be stronger. In men, it proved possible to further dissociate facial cues to muscle and fat mass which both contributed to strength perception. The thesis demonstrates that facial cues used in the evaluation of masculinity and strength are linked to bodily characteristics associated with sex differences and actual strength, namely height, weight, muscularity and adiposity. My findings therefore support the hypothesis that perceptions have an adaptive origin.Meaning, sociality and dialog in bonobo (Pan paniscus) gestural communication : an observational study at the Milwaukee County ZooOrr, Elizabethhttps://hdl.handle.net/10023/119532019-04-01T10:40:34Z2014-04-01T00:00:00ZApes use gestures in an intentional and highly flexible manner. It has been proposed that human language originated in gestural communication and therefore ape gestures have been of great interest to primatologists and psychologists alike. The extensive, flexible and intentional nature of ape gestural communication may also provide new insights to the study of social regulation as large communicative systems are thought to be useful in navigating complex social landscapes. To date studies of bonobos and their use of gestures has occurred in limited contexts and therefore the known repertoire of bonobos is relatively small. It is also unknown as to what bonobos use gestures for and whether they use those gestures flexibly in order to regulate their social relationships. To investigate these questions I studied a captive population of bonobos for 12 months at the Milwaukee County Zoo, Wisconsin, USA. Milwaukee bonobos used 55 gesture types over the course of the study period. I found that bonobos have particular goals behind their signalling and that bonobos used gestures consistently for specific goals and that the same gestures were used for the same goals across signallers. It was therefore possible to identify to meanings behind over half of the gestures within the bonobo repertoire. Even though the meanings of gestures were consistent across signallers, the age and sex of a signaller influenced what context and for what purpose he or she used gestural communication. Particular types of signallers used gestures for particular goals and directed those gestures towards particular recipients. Bonobos also used gestures within dialog during special circumstances in order to coordinate asymmetrical interactions. These results indicate that gestural communication is an excellent medium for investigating the influence a large, intentional and flexible communication system has on managing a complex social network.
2014-04-01T00:00:00ZOrr, ElizabethApes use gestures in an intentional and highly flexible manner. It has been proposed that human language originated in gestural communication and therefore ape gestures have been of great interest to primatologists and psychologists alike. The extensive, flexible and intentional nature of ape gestural communication may also provide new insights to the study of social regulation as large communicative systems are thought to be useful in navigating complex social landscapes. To date studies of bonobos and their use of gestures has occurred in limited contexts and therefore the known repertoire of bonobos is relatively small. It is also unknown as to what bonobos use gestures for and whether they use those gestures flexibly in order to regulate their social relationships. To investigate these questions I studied a captive population of bonobos for 12 months at the Milwaukee County Zoo, Wisconsin, USA. Milwaukee bonobos used 55 gesture types over the course of the study period. I found that bonobos have particular goals behind their signalling and that bonobos used gestures consistently for specific goals and that the same gestures were used for the same goals across signallers. It was therefore possible to identify to meanings behind over half of the gestures within the bonobo repertoire. Even though the meanings of gestures were consistent across signallers, the age and sex of a signaller influenced what context and for what purpose he or she used gestural communication. Particular types of signallers used gestures for particular goals and directed those gestures towards particular recipients. Bonobos also used gestures within dialog during special circumstances in order to coordinate asymmetrical interactions. These results indicate that gestural communication is an excellent medium for investigating the influence a large, intentional and flexible communication system has on managing a complex social network.A comparative cognition perspective on the production and use of visual signals by African savannah elephants (Loxodonta africana)Smet, Anna F.https://hdl.handle.net/10023/118602022-08-29T13:49:18Z2015-02-01T00:00:00ZElephants’ complex societies, well-developed communication systems, evolutionary history and close working relationship with humans make them an important species for studies of cognition but research on elephant cognition is sparse. In this thesis I aim to illuminate the social cognition involved in the interpretation and production of visual signals by African elephants (Loxodonta africana). My results are intended to contribute to the cross-species literature on social cognition and help to elucidate wild elephant social behaviour. I studied captive elephants, housed at an elephant-back safari company in Victoria Falls, and wild elephants in Hwange National Park, both in Zimbabwe. Wild elephants display a vast array of postures, actions and signals. I found that elephants recognise visual attentiveness in others when they signal silently, producing more signals when their audience can see them, and using the body and face orientation of an audience to judge their attention. When responding to typically human visual signals, elephants immediately responded correctly to deictic gestures, including variants of pointing that they were unlikely to have already experienced. These results indicate elephants’ astonishing sensitivity to even subtle social cues. I found no indication that elephants reason about mental states such as false beliefs, or rationality; however, limitations of the experimental design meant I was unlikely to find such an ability even if it is present in elephants. Furthermore, I discovered that elephants have a form of referential indication in their natural communication in the wild. Elephants match their direction of attention with a type of trunk action produced by a group member. Attending to human-like signals, and interpreting them as communicative is an advantage for any animal working with humans and that ability might explain the choice of species that are ancestors of today’s domestic animals.
2015-02-01T00:00:00ZSmet, Anna F.Elephants’ complex societies, well-developed communication systems, evolutionary history and close working relationship with humans make them an important species for studies of cognition but research on elephant cognition is sparse. In this thesis I aim to illuminate the social cognition involved in the interpretation and production of visual signals by African elephants (Loxodonta africana). My results are intended to contribute to the cross-species literature on social cognition and help to elucidate wild elephant social behaviour. I studied captive elephants, housed at an elephant-back safari company in Victoria Falls, and wild elephants in Hwange National Park, both in Zimbabwe. Wild elephants display a vast array of postures, actions and signals. I found that elephants recognise visual attentiveness in others when they signal silently, producing more signals when their audience can see them, and using the body and face orientation of an audience to judge their attention. When responding to typically human visual signals, elephants immediately responded correctly to deictic gestures, including variants of pointing that they were unlikely to have already experienced. These results indicate elephants’ astonishing sensitivity to even subtle social cues. I found no indication that elephants reason about mental states such as false beliefs, or rationality; however, limitations of the experimental design meant I was unlikely to find such an ability even if it is present in elephants. Furthermore, I discovered that elephants have a form of referential indication in their natural communication in the wild. Elephants match their direction of attention with a type of trunk action produced by a group member. Attending to human-like signals, and interpreting them as communicative is an advantage for any animal working with humans and that ability might explain the choice of species that are ancestors of today’s domestic animals.Social learning and social behaviour in two mixed-species communities of tufted capuchins (Sapajus sp.) and common squirrel monkeys (Saimiri sciureus)Messer, Emily Jane Elizabethhttps://hdl.handle.net/10023/114152018-11-02T15:48:15Z2013-08-01T00:00:00ZPrimates are known for being highly social species, living in groups of various compositions with different social structures. The study of social or observational learning has largely focussed on investigating non-human primates’ abilities to imitate, with a more recent shift towards examining the social context of social learning. This shift has presented opportunities to investigate how the social context of different species affects the diffusion of socially learnt behaviours.
In this thesis, I set out to monitor the spread of different experimentally seeded and naturally occurring socially learned behaviours in brown (tufted) capuchin monkeys (Sapajus sp.) and common squirrel monkeys (Saimiri sciureus).These species were selected as they form mixed species groups in the wild, and display marked differences in their social tolerances, thus presenting the opportunity to investigate conspecific and heterospecific social learning in related but differently bonded social groups. My results show evidence of social learning from conspecifics in capuchin and squirrel monkeys, attesting to that already documented in capuchin monkeys and indicating for the first time, that common squirrel monkeys can learn socially. Additionally, I demonstrate that capuchin monkeys are influenced by squirrel monkeys when foraging for food in mixed species groups. Furthermore, although squirrel monkeys are not as socially tolerant as capuchin monkeys, individuals who were better connected within the foraging test area learned experimentally-seeded techniques of models faster and more faithfully. When performing socially contagious anointing behaviours, regardless of tufted capuchin monkeys being influenced by the amount of resources provided for them to anoint with, they still performed more socially anointing than has been previously documented in other captive species, corroborating the levels of social anointing demonstrated in semi-free ranging groups. Further support was found for anointing demonstrating a social bonding and medicinal function in tufted capuchin monkeys.
2013-08-01T00:00:00ZMesser, Emily Jane ElizabethPrimates are known for being highly social species, living in groups of various compositions with different social structures. The study of social or observational learning has largely focussed on investigating non-human primates’ abilities to imitate, with a more recent shift towards examining the social context of social learning. This shift has presented opportunities to investigate how the social context of different species affects the diffusion of socially learnt behaviours.
In this thesis, I set out to monitor the spread of different experimentally seeded and naturally occurring socially learned behaviours in brown (tufted) capuchin monkeys (Sapajus sp.) and common squirrel monkeys (Saimiri sciureus).These species were selected as they form mixed species groups in the wild, and display marked differences in their social tolerances, thus presenting the opportunity to investigate conspecific and heterospecific social learning in related but differently bonded social groups. My results show evidence of social learning from conspecifics in capuchin and squirrel monkeys, attesting to that already documented in capuchin monkeys and indicating for the first time, that common squirrel monkeys can learn socially. Additionally, I demonstrate that capuchin monkeys are influenced by squirrel monkeys when foraging for food in mixed species groups. Furthermore, although squirrel monkeys are not as socially tolerant as capuchin monkeys, individuals who were better connected within the foraging test area learned experimentally-seeded techniques of models faster and more faithfully. When performing socially contagious anointing behaviours, regardless of tufted capuchin monkeys being influenced by the amount of resources provided for them to anoint with, they still performed more socially anointing than has been previously documented in other captive species, corroborating the levels of social anointing demonstrated in semi-free ranging groups. Further support was found for anointing demonstrating a social bonding and medicinal function in tufted capuchin monkeys.Coordination of joint activities and communication in wild chimpanzees (Pan troglodytes) of the Budongo Forest, UgandaMullins, Carolinehttps://hdl.handle.net/10023/113872018-02-21T10:41:40Z2015-01-01T00:00:00ZEvidence from captive studies suggests that chimpanzees (Pan troglodytes) lack the
motivation to complete cooperative tasks and there is little evidence for communication
that coordinates their behaviour during joint actions or whether individuals have a
shared motivation towards the same goal. Two types of behaviour where individuals are
argued to engage in joint activity are investigated in the Sonso community of wild
chimpanzees in Budongo Forest Reserve, Uganda: joint travel and group hunting. This
study presents evidence from naturalistic observations, and also a playback experiment
to further investigate hunting behaviour. Joint travel appears to have no coordinating
signal or behaviour on a local level, although the use of pant-hoot vocalisations to
coordinate long-distance group travel is supported. In group hunting, bark vocalisations
are associated with initiating a group hunt, indicating their potential role in coordination
of joint action. Bark production also appears to be affected by the social composition of
other hunters, with more barks being produced when other hunters are closer affiliates,
suggesting flexibility in call production. The field experiment exploring joint action in
group hunts utilises the alarm calls of the chimpanzees’ prey species- the Colobus
monkey (Colobus guereza). Alarm calls produced by the monkeys when they were
being hunting by chimpanzees and in response to an eagle stimulus were played back to
dyads of affiliated males, and their vocal and behaviour responses recorded. Results
firstly indicate that chimpanzees recognise different Colobus predator alarm.
Furthermore, half of the trials with the Colobus hunting alarm elicited a vocal response
of barks from both of the males in the experiment, along with joint movement in the
direction of the playback. These initial results from a novel field experiment suggest
that the bark vocalisation is associated with the initiation of joint action in the context of
group hunting.
2015-01-01T00:00:00ZMullins, CarolineEvidence from captive studies suggests that chimpanzees (Pan troglodytes) lack the
motivation to complete cooperative tasks and there is little evidence for communication
that coordinates their behaviour during joint actions or whether individuals have a
shared motivation towards the same goal. Two types of behaviour where individuals are
argued to engage in joint activity are investigated in the Sonso community of wild
chimpanzees in Budongo Forest Reserve, Uganda: joint travel and group hunting. This
study presents evidence from naturalistic observations, and also a playback experiment
to further investigate hunting behaviour. Joint travel appears to have no coordinating
signal or behaviour on a local level, although the use of pant-hoot vocalisations to
coordinate long-distance group travel is supported. In group hunting, bark vocalisations
are associated with initiating a group hunt, indicating their potential role in coordination
of joint action. Bark production also appears to be affected by the social composition of
other hunters, with more barks being produced when other hunters are closer affiliates,
suggesting flexibility in call production. The field experiment exploring joint action in
group hunts utilises the alarm calls of the chimpanzees’ prey species- the Colobus
monkey (Colobus guereza). Alarm calls produced by the monkeys when they were
being hunting by chimpanzees and in response to an eagle stimulus were played back to
dyads of affiliated males, and their vocal and behaviour responses recorded. Results
firstly indicate that chimpanzees recognise different Colobus predator alarm.
Furthermore, half of the trials with the Colobus hunting alarm elicited a vocal response
of barks from both of the males in the experiment, along with joint movement in the
direction of the playback. These initial results from a novel field experiment suggest
that the bark vocalisation is associated with the initiation of joint action in the context of
group hunting.The roles of dopamine and the sodium pump in the spinal control of locomotionPicton, Laurencehttps://hdl.handle.net/10023/113592019-04-01T10:40:42Z2017-01-01T00:00:00ZRhythmically active, locomotor networks of the spinal cord are subject to both
neuromodulation and activity-dependent homeostatic regulation. I first show that the
neuromodulator dopamine exerts potent inhibitory effects on the central pattern generator
(CPG) circuit controlling locomotory swimming in post-embryonic Xenopus tadpoles.
Dopamine, acting endogenously on spinal D2-like receptors, reduces spontaneous fictive
swimming occurrence and shortens, slows and weakens swimming. The mechanism involves
a TTX-resistant hyperpolarisation of rhythmically active CPG neurons, mediated by the direct
opening of a K+ channel with GIRK-like pharmacology. This increases rheobase and reduces
spike probability.
I next explore how sodium pumps contribute to the activity-dependent regulation of the
Xenopus swim circuit, and possible interactions of the pumps with modulators, temperature
and ionic conductances. I characterise the pump-mediated ultra-slow afterhyperpolarisation
(usAHP), and show that monensin, a sodium ionophore, enhances pump activity, converting
the usAHP into a tonic hyperpolarisation; this decreases swim episode duration and cycle
frequency. I also characterise a ZD7288-sensitive Ih current, which is active in excitatory dIN
interneurons and contributes to spiking. Blocking Ih with ZD7288 decreases swim episode
duration and destabilises swim bursts. Both Ih and the usAHP increase with temperature,
which depolarises CPG neurons, decreases input resistance, and increases spike probability;
this increases cycle frequency, but the enhanced usAHP shortens swimming. I also show that
the usAHP is diminished by nitric oxide, but enhanced by dopaminergic signalling.
Finally, I explore sodium pumps in the neonatal mouse. The sodium pump blocker ouabain
increases the duration and frequency of drug- and sensory-induced locomotion, whilst
monensin has opposite effects. Decreasing inter-episode interval also shortens and slows
activity, a relationship abolished by ouabain, implicating sodium pumps in a feedforward motor
memory mechanism. Finally, I show that the effects of ouabain on locomotion are dependent
on dopamine, which enhances a TTX- and ouabain-sensitive usAHP in spinal neurons.
2017-01-01T00:00:00ZPicton, LaurenceRhythmically active, locomotor networks of the spinal cord are subject to both
neuromodulation and activity-dependent homeostatic regulation. I first show that the
neuromodulator dopamine exerts potent inhibitory effects on the central pattern generator
(CPG) circuit controlling locomotory swimming in post-embryonic Xenopus tadpoles.
Dopamine, acting endogenously on spinal D2-like receptors, reduces spontaneous fictive
swimming occurrence and shortens, slows and weakens swimming. The mechanism involves
a TTX-resistant hyperpolarisation of rhythmically active CPG neurons, mediated by the direct
opening of a K+ channel with GIRK-like pharmacology. This increases rheobase and reduces
spike probability.
I next explore how sodium pumps contribute to the activity-dependent regulation of the
Xenopus swim circuit, and possible interactions of the pumps with modulators, temperature
and ionic conductances. I characterise the pump-mediated ultra-slow afterhyperpolarisation
(usAHP), and show that monensin, a sodium ionophore, enhances pump activity, converting
the usAHP into a tonic hyperpolarisation; this decreases swim episode duration and cycle
frequency. I also characterise a ZD7288-sensitive Ih current, which is active in excitatory dIN
interneurons and contributes to spiking. Blocking Ih with ZD7288 decreases swim episode
duration and destabilises swim bursts. Both Ih and the usAHP increase with temperature,
which depolarises CPG neurons, decreases input resistance, and increases spike probability;
this increases cycle frequency, but the enhanced usAHP shortens swimming. I also show that
the usAHP is diminished by nitric oxide, but enhanced by dopaminergic signalling.
Finally, I explore sodium pumps in the neonatal mouse. The sodium pump blocker ouabain
increases the duration and frequency of drug- and sensory-induced locomotion, whilst
monensin has opposite effects. Decreasing inter-episode interval also shortens and slows
activity, a relationship abolished by ouabain, implicating sodium pumps in a feedforward motor
memory mechanism. Finally, I show that the effects of ouabain on locomotion are dependent
on dopamine, which enhances a TTX- and ouabain-sensitive usAHP in spinal neurons.Strategic control processes in episodic memory and beyondMill, Ravi Devhttps://hdl.handle.net/10023/113442019-04-01T10:42:24Z2015-01-01T00:00:00ZThe evaluation of past experience is influenced both by the strength of retrieved
memories and factors in the immediate retrieval environment, including emphasised
goals and cued expectations. However, the laboratory study of episodic memory has
neglected such environmental influences, despite their overt contribution to real-world decision outcomes. The aim of this PhD thesis was to rectify this neglect, and
clarify the interaction of memory evidence and environmental strategies in the
service of strategic memory control. A related aim was to investigate whether control
processes identified in the isolated domain of episodic memory in fact performed a
more general or “cross-domain” function.
An initial series of behavioural experiments (Experiments 1-3) elucidated an
overlooked source of strategic bias in the standard recognition environment – implicit
goal emphasis imparted by question format. Experiment 4 investigated whether the
question bias was commonly enacted across different domains of evaluation,
yielding modest evidence in favour of this underlying cross-domain function.
Experiment 5 instantiated more explicit manipulation of goal emphasis and cued
expectation, and recovered independent and opposing strategic effects of these two
environmental factors, emerging across episodic and non-episodic domains.
Experiment 6 employed a simultaneous EEG-fMRI approach to elucidate the neural
correlates of memory control, identifying a modulation of the late positive event-related potential during the resolution of mnemonic conflict, which was sourced to
BOLD variation in regions of the rostral cingulate zone and intraparietal sulcus.
Experiment 7 used pupillometry to examine pupil-linked autonomic systems that
have also been implicated in memory control, and isolated two distinct components
of the dilation response evoked during environmental conflict – an “early amplitude”
unexpected familiarity effect and a “trailing slope” uncertainty effect. The findings
illuminate the cross-domain underpinnings of an adaptive memory control system,
evidenced in behaviour and across different functional neuroimaging modalities, and
across episodic and non-episodic domains of evaluation.
2015-01-01T00:00:00ZMill, Ravi DevThe evaluation of past experience is influenced both by the strength of retrieved
memories and factors in the immediate retrieval environment, including emphasised
goals and cued expectations. However, the laboratory study of episodic memory has
neglected such environmental influences, despite their overt contribution to real-world decision outcomes. The aim of this PhD thesis was to rectify this neglect, and
clarify the interaction of memory evidence and environmental strategies in the
service of strategic memory control. A related aim was to investigate whether control
processes identified in the isolated domain of episodic memory in fact performed a
more general or “cross-domain” function.
An initial series of behavioural experiments (Experiments 1-3) elucidated an
overlooked source of strategic bias in the standard recognition environment – implicit
goal emphasis imparted by question format. Experiment 4 investigated whether the
question bias was commonly enacted across different domains of evaluation,
yielding modest evidence in favour of this underlying cross-domain function.
Experiment 5 instantiated more explicit manipulation of goal emphasis and cued
expectation, and recovered independent and opposing strategic effects of these two
environmental factors, emerging across episodic and non-episodic domains.
Experiment 6 employed a simultaneous EEG-fMRI approach to elucidate the neural
correlates of memory control, identifying a modulation of the late positive event-related potential during the resolution of mnemonic conflict, which was sourced to
BOLD variation in regions of the rostral cingulate zone and intraparietal sulcus.
Experiment 7 used pupillometry to examine pupil-linked autonomic systems that
have also been implicated in memory control, and isolated two distinct components
of the dilation response evoked during environmental conflict – an “early amplitude”
unexpected familiarity effect and a “trailing slope” uncertainty effect. The findings
illuminate the cross-domain underpinnings of an adaptive memory control system,
evidenced in behaviour and across different functional neuroimaging modalities, and
across episodic and non-episodic domains of evaluation.Neural mechanisms of executive function : the role of the pedunculopontine tegmental nucleus and medial prefrontal cortex in delayed spatial win-shift behaviour in the ratTaylor, Claire L.https://hdl.handle.net/10023/111152019-04-01T10:40:29Z2002-01-01T00:00:00ZThe pedunculopontine tegmental nucleus (PPTg) has been argued to be involved in mediating neural processing relating to executive functions (Winn, 1998). Since it
shares connections with fronto-striatal circuitry this proposal is not surprising. However, research examining the functions of structures within this system has frequently ignored the contribution of PPTg. The delayed spatial win-shift (DSWS)
task is a task that measures spatial working memory and, as such, has been used by
Phillips and colleagues to reveal the involvement of ventral striatal structures in this
form of "executive" behaviour. This suggests that structures interconnected with PFC share in some way frontal functions. As might be expected from its connections, the
involvement of PPTg in the same task has also been demonstrated (Keating & Winn,
2001). The current research was designed to assess further the involvement of PPTg in the DSWS task, and to compare this directly to the involvement of prefrontal cortex (PFC). In order to achieve this, rats with excitotoxic lesions of PPTg and medial PFC were assessed on the DSWS task, in addition to rats with crossed unilateral disconnection of medial PFC/PPTg. Statistically, results demonstrated both PPTg and medial PFC lesions produced similar impairments in the test phase of DSWS, characterised by increased errors, earlier error occurrence, and slower latencies. In contrast, disconnection lesions of medial PFC/PPTg produced an impairment that was fundamentally different. It was concluded that while this supports the importance of PPTg functioning within fronto-striatal systems, the pattern of impairment shown by disconnected rats suggested that this function
may not be executive per se but might be necessary for executive functions to influence behaviour.
2002-01-01T00:00:00ZTaylor, Claire L.The pedunculopontine tegmental nucleus (PPTg) has been argued to be involved in mediating neural processing relating to executive functions (Winn, 1998). Since it
shares connections with fronto-striatal circuitry this proposal is not surprising. However, research examining the functions of structures within this system has frequently ignored the contribution of PPTg. The delayed spatial win-shift (DSWS)
task is a task that measures spatial working memory and, as such, has been used by
Phillips and colleagues to reveal the involvement of ventral striatal structures in this
form of "executive" behaviour. This suggests that structures interconnected with PFC share in some way frontal functions. As might be expected from its connections, the
involvement of PPTg in the same task has also been demonstrated (Keating & Winn,
2001). The current research was designed to assess further the involvement of PPTg in the DSWS task, and to compare this directly to the involvement of prefrontal cortex (PFC). In order to achieve this, rats with excitotoxic lesions of PPTg and medial PFC were assessed on the DSWS task, in addition to rats with crossed unilateral disconnection of medial PFC/PPTg. Statistically, results demonstrated both PPTg and medial PFC lesions produced similar impairments in the test phase of DSWS, characterised by increased errors, earlier error occurrence, and slower latencies. In contrast, disconnection lesions of medial PFC/PPTg produced an impairment that was fundamentally different. It was concluded that while this supports the importance of PPTg functioning within fronto-striatal systems, the pattern of impairment shown by disconnected rats suggested that this function
may not be executive per se but might be necessary for executive functions to influence behaviour.Cognitive and neural processes underlying memory for time and contextPersson, Bjorn Martinhttps://hdl.handle.net/10023/110242019-04-01T10:40:39Z2017-06-20T00:00:00ZThe aim of this thesis is to examine the underlying cognitive and neural processes at play
during retrieval of temporal and contextual source information. This was assessed across
three experimental chapters. In the first experimental chapter, Chapter 2, the neural loci of
context associations were assessed. Rats trained on an odour-context association task were
given lesions to either the Lateral Entorhinal Cortex (LEC) or sham lesions. After surgery,
performance on the odour-context task was assessed. It was hypothesised that memory for
previously learned odour-context associations would be impaired following LEC lesions but
not sham lesions. The results supported this hypothesis, demonstrating impaired memory for
the previously learned odour-context associations in the LEC lesion group compared to the
Sham lesion. In Chapter 3, the underlying retrieval processes used to retrieve time and
context in human memory was assessed across three experiments. It was hypothesised that
time would be remembered accurately using both recollection and familiarity, while correct
context memory should rely on recollection alone. Two out of the three experiments
supported this hypothesis, demonstrating that temporal information can be retrieved using
familiarity in certain instances. The final experimental Chapter 4 used fMRI to extend
Chapter 3 and examine whether neural activity would be greater in regions associated with
recollection during memory for context, while activity in familiarity-related regions would be
higher during memory for time. Results revealed no support for these predictions with no
regions linked to recollection showing greater context-related activity, and no regions
previously linked to familiarity exhibiting increased activation as temporal information was
retrieved. The results are discussed in relation to established recollection and familiarity
frameworks and previous work examining the neural substrates supporting memory for time
and context.
2017-06-20T00:00:00ZPersson, Bjorn MartinThe aim of this thesis is to examine the underlying cognitive and neural processes at play
during retrieval of temporal and contextual source information. This was assessed across
three experimental chapters. In the first experimental chapter, Chapter 2, the neural loci of
context associations were assessed. Rats trained on an odour-context association task were
given lesions to either the Lateral Entorhinal Cortex (LEC) or sham lesions. After surgery,
performance on the odour-context task was assessed. It was hypothesised that memory for
previously learned odour-context associations would be impaired following LEC lesions but
not sham lesions. The results supported this hypothesis, demonstrating impaired memory for
the previously learned odour-context associations in the LEC lesion group compared to the
Sham lesion. In Chapter 3, the underlying retrieval processes used to retrieve time and
context in human memory was assessed across three experiments. It was hypothesised that
time would be remembered accurately using both recollection and familiarity, while correct
context memory should rely on recollection alone. Two out of the three experiments
supported this hypothesis, demonstrating that temporal information can be retrieved using
familiarity in certain instances. The final experimental Chapter 4 used fMRI to extend
Chapter 3 and examine whether neural activity would be greater in regions associated with
recollection during memory for context, while activity in familiarity-related regions would be
higher during memory for time. Results revealed no support for these predictions with no
regions linked to recollection showing greater context-related activity, and no regions
previously linked to familiarity exhibiting increased activation as temporal information was
retrieved. The results are discussed in relation to established recollection and familiarity
frameworks and previous work examining the neural substrates supporting memory for time
and context.Perceptions of intelligence and the attractiveness haloTalamas, Sean N.https://hdl.handle.net/10023/108512019-04-01T10:42:23Z2016-06-01T00:00:00ZPerceptions of intelligence are strongly related to attractiveness and have a
significant impact on first impressions. The introductory chapters (1 – 3) provide an
overview of the literature on attractiveness, halo effects, and intelligence, while the
experimental chapters (4 – 6) explore perceptions of cues to intelligence beyond
attractiveness, individual differences in the susceptibility to the halo, and the accuracy of
perceptions of competence.
Chapter 4 investigated the malleable facial cues of eyelid-openness and mouth
curvature and their influence on perceived intelligence. Attractiveness partially mediated
intelligence impression, but effects of eyelid-openness and subtle smiling enhanced
intelligence ratings independent of attractiveness. These effects were observed and
replicated in between individual (cross-sectional) studies of natural images of adult faces,
child faces, through digital manipulation of individual cues in the same faces, and in a
within individual sleep-restricted sample. Chapter 5 investigated the relationship between
perceived intelligence and attractiveness by exploring whether a raters’ own intelligence
may be related to a stronger endorsement of the perceived intelligence-attractiveness halo.
The correlation between ratings of the perceived intelligence and attractiveness was found
to be stronger for participants who scored higher on an intelligence test than participants
with lower intelligence test scores. Chapter 6 investigated the limiting effects of
attractiveness on perceptions of competence. When statistically controlling for the
attractiveness halo, academic performance could be predicted from judgments of
conscientiousness but not from ratings of intelligence.
Thus this thesis demonstrates that malleable facial cues can influence perceptions
of intelligence independent of attractiveness, identifies an individual difference that
influences endorsement of the intelligence-attractiveness halo, and shows the limiting
effects of the attractiveness halo on potentially accurate perceptions of academic
performance. Collectively these findings provide evidence of the powerful influence of
attractiveness on perceptions of intelligence; such work is necessary if we are to mitigate
such bias.
2016-06-01T00:00:00ZTalamas, Sean N.Perceptions of intelligence are strongly related to attractiveness and have a
significant impact on first impressions. The introductory chapters (1 – 3) provide an
overview of the literature on attractiveness, halo effects, and intelligence, while the
experimental chapters (4 – 6) explore perceptions of cues to intelligence beyond
attractiveness, individual differences in the susceptibility to the halo, and the accuracy of
perceptions of competence.
Chapter 4 investigated the malleable facial cues of eyelid-openness and mouth
curvature and their influence on perceived intelligence. Attractiveness partially mediated
intelligence impression, but effects of eyelid-openness and subtle smiling enhanced
intelligence ratings independent of attractiveness. These effects were observed and
replicated in between individual (cross-sectional) studies of natural images of adult faces,
child faces, through digital manipulation of individual cues in the same faces, and in a
within individual sleep-restricted sample. Chapter 5 investigated the relationship between
perceived intelligence and attractiveness by exploring whether a raters’ own intelligence
may be related to a stronger endorsement of the perceived intelligence-attractiveness halo.
The correlation between ratings of the perceived intelligence and attractiveness was found
to be stronger for participants who scored higher on an intelligence test than participants
with lower intelligence test scores. Chapter 6 investigated the limiting effects of
attractiveness on perceptions of competence. When statistically controlling for the
attractiveness halo, academic performance could be predicted from judgments of
conscientiousness but not from ratings of intelligence.
Thus this thesis demonstrates that malleable facial cues can influence perceptions
of intelligence independent of attractiveness, identifies an individual difference that
influences endorsement of the intelligence-attractiveness halo, and shows the limiting
effects of the attractiveness halo on potentially accurate perceptions of academic
performance. Collectively these findings provide evidence of the powerful influence of
attractiveness on perceptions of intelligence; such work is necessary if we are to mitigate
such bias.In vivo and in vitro studies of positive allosteric modulation of the NMDA receptorBrazaitis, Casmira T.https://hdl.handle.net/10023/104952019-04-01T10:41:41Z2017-06-20T00:00:00ZDysfunction of the N-methyl-D-aspartate (NMDA) receptor is thought to contribute to the cognitive deficits of many neurodegenerative diseases and psychiatric disorders. Cognitive symptoms of Alzheimer’s disease can be treated with NMDA receptor antagonists or drugs targeting the cholinergic system; however, there are no effective treatments for cognitive deficits of schizophrenia or Huntington’s disease. With the discovery of a potent and selective allosteric modulator of the NMDA receptor, there is the possibility of new treatments based on NMDA receptor functional-enhancement through neuroactive steroids, closely related in structure to the endogenous neurosteroid, cerebrosterol. The aim of this thesis was to examine steroidal modulation of the NMDA receptor both in vitro and in vivo. In chapter 2, NMDA receptor enhancement of both the synthetic and endogenous neuroactive steroids was assessed in neurons maintained in cell culture using calcium imaging techniques. Sulphation of the steroids greatly increased the efficacy of NMDA receptor enhancement compared to the unsulphated steroids. Chapters 3 and 4 investigate the potential for neuroactive steroids to treat cognitive impairments of Huntington’s disease. Using a mouse model, tests were selected that were analogous to those in which patients are impaired; however, no impairments were found in the mouse model. Chapter 5, therefore, used a different model of cognitive impairment – namely, rats with a set-shifting impairment, as is seen in many psychiatric and neurological disorders, including Huntington’s disease – to assess the effect of the synthetic steroid administration. Unfortunately, the rats did not show the expected impairment. The lack of reliable animal models compromised testing the efficacy of these promising NMDA receptor positive allosteric modulators. Nevertheless, the promising in vitro results suggest that there could still be therapeutic potential. In addition, the compound is a useful research tool for exploring NMDA receptor function in health and disease.
2017-06-20T00:00:00ZBrazaitis, Casmira T.Dysfunction of the N-methyl-D-aspartate (NMDA) receptor is thought to contribute to the cognitive deficits of many neurodegenerative diseases and psychiatric disorders. Cognitive symptoms of Alzheimer’s disease can be treated with NMDA receptor antagonists or drugs targeting the cholinergic system; however, there are no effective treatments for cognitive deficits of schizophrenia or Huntington’s disease. With the discovery of a potent and selective allosteric modulator of the NMDA receptor, there is the possibility of new treatments based on NMDA receptor functional-enhancement through neuroactive steroids, closely related in structure to the endogenous neurosteroid, cerebrosterol. The aim of this thesis was to examine steroidal modulation of the NMDA receptor both in vitro and in vivo. In chapter 2, NMDA receptor enhancement of both the synthetic and endogenous neuroactive steroids was assessed in neurons maintained in cell culture using calcium imaging techniques. Sulphation of the steroids greatly increased the efficacy of NMDA receptor enhancement compared to the unsulphated steroids. Chapters 3 and 4 investigate the potential for neuroactive steroids to treat cognitive impairments of Huntington’s disease. Using a mouse model, tests were selected that were analogous to those in which patients are impaired; however, no impairments were found in the mouse model. Chapter 5, therefore, used a different model of cognitive impairment – namely, rats with a set-shifting impairment, as is seen in many psychiatric and neurological disorders, including Huntington’s disease – to assess the effect of the synthetic steroid administration. Unfortunately, the rats did not show the expected impairment. The lack of reliable animal models compromised testing the efficacy of these promising NMDA receptor positive allosteric modulators. Nevertheless, the promising in vitro results suggest that there could still be therapeutic potential. In addition, the compound is a useful research tool for exploring NMDA receptor function in health and disease.The evolutionary origins of executive functions : behavioural control in humans and chimpanzeesMayer, Carolina Patriciahttps://hdl.handle.net/10023/104942019-09-30T11:31:48Z2015-01-01T00:00:00ZExecutive functions (EFs) are a set of cognitive operations, including working memory, inhibitory
control and attention shifting, that underpin accurate, flexible and coordinated behaviour in
many problem-solving contexts. While it seems likely that humans surpass nonhuman animals
in EFs, previous research into the evolutionary origins of EFs is limited and lacks systematic
comparisons of EFs in human and nonhuman animals.
In this thesis, I aimed to overcome these limitations by developing a test battery to study EFs in
our closest primate relative, the chimpanzee. Using an individual differences approach, I
investigated the performance of 19 chimpanzees on several EF tasks and extracted two factors
in an exploratory factor analysis accounting for 70.9 % of the variability. The two measures of
working memory loaded onto one factor, suggesting that a common cognitive process underlay
performance on both tasks. This factor could be clearly differentiated from a well-established
measure of attention shifting, loading onto a second factor. In addition, the measures of
inhibitory control did not contribute to a unique factor. Intriguingly, the emerging structure of
separable EF processes, paralleled the EF structure suggested for human adults (Miyake et al,
2012).
The subsequent comparison of a sub-sample of chimpanzees (n = 12; excluding aged
individuals), pre-schoolers (n = 36) and undergraduates (n = 16) on two selected EF tests
revealed impressive EF capacities of chimpanzees. Chimpanzees could deal with interference
in working memory at levels comparable to four and five year-olds. Additionally, the ability of
chimpanzees to shift attention was not significantly different from four year-olds; however, five-
year-olds outperformed their primate relatives. My work suggests that important aspects of EFs are shared between humans and chimpanzees; while performance differences in EFs emerge
late in human ontogeny. The implications of my results for theories on human cognitive
evolution are discussed.
2015-01-01T00:00:00ZMayer, Carolina PatriciaExecutive functions (EFs) are a set of cognitive operations, including working memory, inhibitory
control and attention shifting, that underpin accurate, flexible and coordinated behaviour in
many problem-solving contexts. While it seems likely that humans surpass nonhuman animals
in EFs, previous research into the evolutionary origins of EFs is limited and lacks systematic
comparisons of EFs in human and nonhuman animals.
In this thesis, I aimed to overcome these limitations by developing a test battery to study EFs in
our closest primate relative, the chimpanzee. Using an individual differences approach, I
investigated the performance of 19 chimpanzees on several EF tasks and extracted two factors
in an exploratory factor analysis accounting for 70.9 % of the variability. The two measures of
working memory loaded onto one factor, suggesting that a common cognitive process underlay
performance on both tasks. This factor could be clearly differentiated from a well-established
measure of attention shifting, loading onto a second factor. In addition, the measures of
inhibitory control did not contribute to a unique factor. Intriguingly, the emerging structure of
separable EF processes, paralleled the EF structure suggested for human adults (Miyake et al,
2012).
The subsequent comparison of a sub-sample of chimpanzees (n = 12; excluding aged
individuals), pre-schoolers (n = 36) and undergraduates (n = 16) on two selected EF tests
revealed impressive EF capacities of chimpanzees. Chimpanzees could deal with interference
in working memory at levels comparable to four and five year-olds. Additionally, the ability of
chimpanzees to shift attention was not significantly different from four year-olds; however, five-
year-olds outperformed their primate relatives. My work suggests that important aspects of EFs are shared between humans and chimpanzees; while performance differences in EFs emerge
late in human ontogeny. The implications of my results for theories on human cognitive
evolution are discussed.Attention regulation and behavioural flexibility in rats with relevance to schizophreniaWhyte, Alonzohttps://hdl.handle.net/10023/104832019-04-01T10:40:33Z2017-06-20T00:00:00ZSchizophrenia is a neuropsychological disorder in which the neural systems which regulate attention allocation, primarily the dorsolateral prefrontal cortex, are dysfunctional, resulting in deficient gating of attention to irrelevant inputs from the environment. This sensory processing dysfunction hinders goal-directed behaviour to the extent that the subsequent cognitive deficits of schizophrenia prevent many chronic patients from leading normal lives. It is the onus of neuroscience to understand the nature of deficits induced by the disorder, thus providing target mechanisms for remediation of those deficits in patients. To accomplish this, manipulations in rats with relevance to schizophrenia are examined in assays with translation to human neurobiology and behaviour. In this thesis, three manipulations with relevance to schizophrenia, were examined for attentional regulation in the attentional set-shifting task, and similar assays, to determine how different forms of schizophrenia-related pathology influence attentional regulation and behavioural flexibility.
The foremost findings of the experiments herein were that manipulations inducing schizophrenia-related neurobiology, resulted in impaired performance in extradimensional set-shifting and reversal learning. These deficits were found following: acute inhibition of the mPFC in adult rats, in adult rats who had been exposed to a glutamate receptor antagonist during the neonatal period of development, and/or in adult rats who had gestational disruption of neuron proliferation. Across all three manipulations, a clear behavioural pattern of deficient sensory gating, evidenced by responding to irrelevant stimuli during the set-shifting task was found.
These findings suggest that at the core of the cognitive deficits in schizophrenia is the ‘loosening of associations’ such that patients suffer the inability to regulate attention, and limit sensory processing to relevant information. The subsequent aberrant learning about irrelevant information then impairs performance during goal-directed behaviours.
2017-06-20T00:00:00ZWhyte, AlonzoSchizophrenia is a neuropsychological disorder in which the neural systems which regulate attention allocation, primarily the dorsolateral prefrontal cortex, are dysfunctional, resulting in deficient gating of attention to irrelevant inputs from the environment. This sensory processing dysfunction hinders goal-directed behaviour to the extent that the subsequent cognitive deficits of schizophrenia prevent many chronic patients from leading normal lives. It is the onus of neuroscience to understand the nature of deficits induced by the disorder, thus providing target mechanisms for remediation of those deficits in patients. To accomplish this, manipulations in rats with relevance to schizophrenia are examined in assays with translation to human neurobiology and behaviour. In this thesis, three manipulations with relevance to schizophrenia, were examined for attentional regulation in the attentional set-shifting task, and similar assays, to determine how different forms of schizophrenia-related pathology influence attentional regulation and behavioural flexibility.
The foremost findings of the experiments herein were that manipulations inducing schizophrenia-related neurobiology, resulted in impaired performance in extradimensional set-shifting and reversal learning. These deficits were found following: acute inhibition of the mPFC in adult rats, in adult rats who had been exposed to a glutamate receptor antagonist during the neonatal period of development, and/or in adult rats who had gestational disruption of neuron proliferation. Across all three manipulations, a clear behavioural pattern of deficient sensory gating, evidenced by responding to irrelevant stimuli during the set-shifting task was found.
These findings suggest that at the core of the cognitive deficits in schizophrenia is the ‘loosening of associations’ such that patients suffer the inability to regulate attention, and limit sensory processing to relevant information. The subsequent aberrant learning about irrelevant information then impairs performance during goal-directed behaviours.Practice mentors' attitudes and perspectives of interprofessional working, and interprofessional practice learning for students : a mixed-methods case studyO'Carroll, Veronicahttps://hdl.handle.net/10023/104822023-04-06T13:23:51Z2017-06-20T00:00:00ZThe demands on health and social care organisations require professions to work more collaboratively. During pre-registration training, health care and social work students learn within practice settings, supported by practice mentors. These settings are rich learning environments to experience interprofessional working (IPW) and for students to learn together through interprofessional practice learning (IPPL). There is, however, evidence that students’ experiences of both are varied or limited. The value placed on IPW, and IPPL, is therefore of interest. This thesis will investigate practice mentors’ attitudes to IPW and IPPL, and explore their perspectives of the enablers and barriers to these occurring in practice settings.
A mixed-methods case study approach was used to measure the attitudes of practice mentors from health and social work, and to identify enablers and barriers to IPW, and IPPL for students. Online surveys and semi-structured face to face interviews were carried out with a range of professions within one Scottish health board and associated local authority.
Results showed that attitudes to IPW, and IPPL for students were generally positive. Attitudes were not significantly affected by governing body, gender, area of work, years of experience, or prior experience of IPE. IPW was perceived to be enabled by shared processes and policies, IPPL for staff, effective communication, established teams, and shared processes and policies. Proximity to other professions and shared spaces encouraged informal communication and positive interprofessional relationships. Regular structured IPPL opportunities for students were limited. However, where opportunities did occur, this was linked to areas where practice mentors perceived that there was a strong interprofessional team identity.
Although attitudes to IPW, and IPPL for students are positive, further work is needed to identify systems for improving IPW, to strengthen professions’ identity as interprofessional teams, and to increase IPPL opportunities for students.
2017-06-20T00:00:00ZO'Carroll, VeronicaThe demands on health and social care organisations require professions to work more collaboratively. During pre-registration training, health care and social work students learn within practice settings, supported by practice mentors. These settings are rich learning environments to experience interprofessional working (IPW) and for students to learn together through interprofessional practice learning (IPPL). There is, however, evidence that students’ experiences of both are varied or limited. The value placed on IPW, and IPPL, is therefore of interest. This thesis will investigate practice mentors’ attitudes to IPW and IPPL, and explore their perspectives of the enablers and barriers to these occurring in practice settings.
A mixed-methods case study approach was used to measure the attitudes of practice mentors from health and social work, and to identify enablers and barriers to IPW, and IPPL for students. Online surveys and semi-structured face to face interviews were carried out with a range of professions within one Scottish health board and associated local authority.
Results showed that attitudes to IPW, and IPPL for students were generally positive. Attitudes were not significantly affected by governing body, gender, area of work, years of experience, or prior experience of IPE. IPW was perceived to be enabled by shared processes and policies, IPPL for staff, effective communication, established teams, and shared processes and policies. Proximity to other professions and shared spaces encouraged informal communication and positive interprofessional relationships. Regular structured IPPL opportunities for students were limited. However, where opportunities did occur, this was linked to areas where practice mentors perceived that there was a strong interprofessional team identity.
Although attitudes to IPW, and IPPL for students are positive, further work is needed to identify systems for improving IPW, to strengthen professions’ identity as interprofessional teams, and to increase IPPL opportunities for students.Understanding collective action in repressive contexts : the role of perceived risk in shaping collective action intentionsAyanian, Arin H.https://hdl.handle.net/10023/103322023-09-29T02:02:25Z2017-06-20T00:00:00ZThe aim of the present research is to advance a general predictive model of the social psychological processes underlying collective action in contexts where collective action is met with significant repression by the authorities. The model integrates the recent advancements in the collective action literature and examines the unique predictive role of anger and fear (emotional pathway), political, identity consolidation and participative efficacies (instrumental pathway), politicised identification (identity pathway) as well as moral obligation, over and above past participation. Moreover, the research investigates how perceived risk, due to government sanctions, shapes these antecedents and the willingness to engage in collective action. Five survey studies (Studies 1 to 5) test this model in various repressive contexts (i.e., Egypt, Hong Kong, Russia, Ukraine, and Turkey). In addition, one experimental study (Study 6) examines the causal relation between perceived risk and (a) the antecedents of collective action and (b) the action intentions in a British sample. The results confirm the intensifying role of perceived risk, whereby it indirectly spurs further resistance through shaping the antecedents of collective action. The results also suggest that protesters are intrinsically motivated to engage in collective action when placed under risk. Specifically, although not motivated by political efficacy, protesters are strategic as they are motivated by the likelihood to consolidate the identity of their protest movement and the likelihood of their own participation to incrementally contribute to achieving the desired goals. Moreover, they are emotional, politicised and dutiful as their outrage towards how the authorities treat the protesters, their identification with their protest movement, as well as their sense of moral responsibility encourage them to take action despite the risks.
2017-06-20T00:00:00ZAyanian, Arin H.The aim of the present research is to advance a general predictive model of the social psychological processes underlying collective action in contexts where collective action is met with significant repression by the authorities. The model integrates the recent advancements in the collective action literature and examines the unique predictive role of anger and fear (emotional pathway), political, identity consolidation and participative efficacies (instrumental pathway), politicised identification (identity pathway) as well as moral obligation, over and above past participation. Moreover, the research investigates how perceived risk, due to government sanctions, shapes these antecedents and the willingness to engage in collective action. Five survey studies (Studies 1 to 5) test this model in various repressive contexts (i.e., Egypt, Hong Kong, Russia, Ukraine, and Turkey). In addition, one experimental study (Study 6) examines the causal relation between perceived risk and (a) the antecedents of collective action and (b) the action intentions in a British sample. The results confirm the intensifying role of perceived risk, whereby it indirectly spurs further resistance through shaping the antecedents of collective action. The results also suggest that protesters are intrinsically motivated to engage in collective action when placed under risk. Specifically, although not motivated by political efficacy, protesters are strategic as they are motivated by the likelihood to consolidate the identity of their protest movement and the likelihood of their own participation to incrementally contribute to achieving the desired goals. Moreover, they are emotional, politicised and dutiful as their outrage towards how the authorities treat the protesters, their identification with their protest movement, as well as their sense of moral responsibility encourage them to take action despite the risks.The development and neuromodulation of motor control systems in pro-metamorphic Xenopus laevis frog tadpolesCurrie, Stephen Paulhttps://hdl.handle.net/10023/101992019-04-01T10:40:59Z2014-01-01T00:00:00ZMy thesis has accomplished 3 significant contributions to neuroscience. Firstly, I
have discovered a novel example of vertebrate deep-brain photoreception.
Spontaneously generated fictive locomotion from the isolated nervous system of
pro-metamorphic Xenopus tadpoles is sensitive to the ambient light conditions,
despite input from the classical photoreceptive tissues of the retina and pineal
complex being absent. The photosensitivity is found to be tuned to short
wavelength UV light and is localised to a small region of the caudal diencephalon.
Within this region, I have discovered a population of neurons immuno-positive for
a UV-specific opsin protein, suggesting they are the means of phototransduction.
This may be a hitherto overlooked mechanism linking environmental luminance to
motor behaviour. Secondly, I have advanced the collective knowledge of how both
nitric oxide and dopamine contribute to neuromodulation within motor control
systems. Nitric oxide is shown to have an excitatory effect on the occurrence of
spontaneous locomotor activity, representing a switch in its role from earlier in
Xenopus development. Moreover, this excitatory effect is found to be mediated in
the brainstem despite nitric oxide being shown to depolarise spinal neurons.
Thirdly, I have developed a new preparation for patch-clamp recording in pro-metamorphic Xenopus tadpoles. My data suggest there are several changes to the
cellular properties of neurons in the older animals compared with the embryonic
tadpole; there appears to be an addition of Ih and K[sub](Ca) channels and the presence
of tonically active and intrinsically rhythmogenic neurons. In addition, I have
shown that at low doses dopamine acts via D2-like to hyperpolarise the membrane
potential of spinal neurons, while at higher doses dopamine depolarises spinal
neurons. These initial data corroborate previously reported evidence that
dopamine has opposing effects on motor output via differential activation of
dopamine receptor subtypes in Xenopus tadpoles.
2014-01-01T00:00:00ZCurrie, Stephen PaulMy thesis has accomplished 3 significant contributions to neuroscience. Firstly, I
have discovered a novel example of vertebrate deep-brain photoreception.
Spontaneously generated fictive locomotion from the isolated nervous system of
pro-metamorphic Xenopus tadpoles is sensitive to the ambient light conditions,
despite input from the classical photoreceptive tissues of the retina and pineal
complex being absent. The photosensitivity is found to be tuned to short
wavelength UV light and is localised to a small region of the caudal diencephalon.
Within this region, I have discovered a population of neurons immuno-positive for
a UV-specific opsin protein, suggesting they are the means of phototransduction.
This may be a hitherto overlooked mechanism linking environmental luminance to
motor behaviour. Secondly, I have advanced the collective knowledge of how both
nitric oxide and dopamine contribute to neuromodulation within motor control
systems. Nitric oxide is shown to have an excitatory effect on the occurrence of
spontaneous locomotor activity, representing a switch in its role from earlier in
Xenopus development. Moreover, this excitatory effect is found to be mediated in
the brainstem despite nitric oxide being shown to depolarise spinal neurons.
Thirdly, I have developed a new preparation for patch-clamp recording in pro-metamorphic Xenopus tadpoles. My data suggest there are several changes to the
cellular properties of neurons in the older animals compared with the embryonic
tadpole; there appears to be an addition of Ih and K[sub](Ca) channels and the presence
of tonically active and intrinsically rhythmogenic neurons. In addition, I have
shown that at low doses dopamine acts via D2-like to hyperpolarise the membrane
potential of spinal neurons, while at higher doses dopamine depolarises spinal
neurons. These initial data corroborate previously reported evidence that
dopamine has opposing effects on motor output via differential activation of
dopamine receptor subtypes in Xenopus tadpoles.Regulation of mammalian spinal locomotor networks by glial cellsActon, Davidhttps://hdl.handle.net/10023/101332021-02-02T03:06:45Z2017-06-01T00:00:00ZNetworks of interneurons within the spinal cord coordinate the rhythmic activation of muscles during locomotion. These networks are subject to extensive neuromodulation, ensuring appropriate behavioural output. Astrocytes are proposed to detect neuronal activity via Gαq-linked G-protein coupled receptors and to secrete neuromodulators in response. However, there is currently a paucity of evidence that astrocytic information processing of this kind is important in behaviour. Here, it is shown that protease-activated receptor-1 (PAR1), a Gαq-linked receptor, is preferentially expressed by glia in the spinal cords of postnatal mice. During ongoing locomotor-related network activity in isolated spinal cords, PAR1 activation stimulates release of adenosine triphosphate (ATP), which is hydrolysed to adenosine extracellularly. Adenosine then activates A1 receptors to reduce the frequency of locomotor-related bursting recorded from ventral roots. This entails inhibition of D1 dopamine receptors, activation of which enhances burst frequency. The effect of A1 blockade scales with network activity, consistent with activity-dependent production of adenosine by glia. Astrocytes also regulate activity by controlling the availability of D-serine or glycine, both of which act as co-agonists of glutamate at N-methyl-D-aspartate receptors (NMDARs). The importance of NMDAR regulation for locomotor-related activity is demonstrated by blockade of NMDARs, which reduces burst frequency and amplitude. Bath-applied D-serine increases the frequency of locomotor-related bursting but not intense synchronous bursting produced by blockade of inhibitory transmission, implying activity-dependent regulation of co-agonist availability. Depletion of endogenous D-serine increases the frequency of locomotor-related but not synchronous bursting, indicating that D-serine is required at a subset of NMDARs expressed by inhibitory interneurons. Blockade of the astrocytic glycine transporter GlyT1 increases the frequency of locomotor-related activity, but application of glycine has no effect, indicating that GlyT1 regulates glycine at excitatory synapses. These results indicate that glia play an important role in regulating the output of spinal locomotor networks.
2017-06-01T00:00:00ZActon, DavidNetworks of interneurons within the spinal cord coordinate the rhythmic activation of muscles during locomotion. These networks are subject to extensive neuromodulation, ensuring appropriate behavioural output. Astrocytes are proposed to detect neuronal activity via Gαq-linked G-protein coupled receptors and to secrete neuromodulators in response. However, there is currently a paucity of evidence that astrocytic information processing of this kind is important in behaviour. Here, it is shown that protease-activated receptor-1 (PAR1), a Gαq-linked receptor, is preferentially expressed by glia in the spinal cords of postnatal mice. During ongoing locomotor-related network activity in isolated spinal cords, PAR1 activation stimulates release of adenosine triphosphate (ATP), which is hydrolysed to adenosine extracellularly. Adenosine then activates A1 receptors to reduce the frequency of locomotor-related bursting recorded from ventral roots. This entails inhibition of D1 dopamine receptors, activation of which enhances burst frequency. The effect of A1 blockade scales with network activity, consistent with activity-dependent production of adenosine by glia. Astrocytes also regulate activity by controlling the availability of D-serine or glycine, both of which act as co-agonists of glutamate at N-methyl-D-aspartate receptors (NMDARs). The importance of NMDAR regulation for locomotor-related activity is demonstrated by blockade of NMDARs, which reduces burst frequency and amplitude. Bath-applied D-serine increases the frequency of locomotor-related bursting but not intense synchronous bursting produced by blockade of inhibitory transmission, implying activity-dependent regulation of co-agonist availability. Depletion of endogenous D-serine increases the frequency of locomotor-related but not synchronous bursting, indicating that D-serine is required at a subset of NMDARs expressed by inhibitory interneurons. Blockade of the astrocytic glycine transporter GlyT1 increases the frequency of locomotor-related activity, but application of glycine has no effect, indicating that GlyT1 regulates glycine at excitatory synapses. These results indicate that glia play an important role in regulating the output of spinal locomotor networks.Virtuous violence : a social identity approach to understanding the politics of prejudice in inter-group relationsRath, Rakshihttps://hdl.handle.net/10023/98922022-08-29T13:52:45Z2016-11-30T00:00:00ZThe aim of the thesis is to provide a social identity account of the politics of mobilisation: based on hatred mostly, in contrast with accounts of solidarity. The bulk of the thesis concentrates on exploring how and why is prejudice in the form of hatred mobilised in inter-group relations. Three studies parse the structure of hate discourse of Hindu right-wing groups in India. Study 1 and study 2 are qualitative studies that analyse the production of hate in two mediums of communication, while study 3 is an experimental study demonstrating the reception of hate. The studies analyse the structure of hate discourse with the theoretical lens of a social identity framework to explicate a context of categories and category-relations, while colouring in the contents of the categories with data from India. The first contention is, if a virtuous in-group can be construed as under threat from an out-group, then, the annihilation of the other can be justified as the defence of virtue. In the other words, violence becomes virtuous. The second contention is, the process that motivates out-group hate discourse derives from struggles over intra-group authority. That is, out-group threats are invoked in order to condemn political rivals for in-group power as not representing the group and not defending group interests. This sets up the foil for the leader to position ‘self’ as the ideal leader who protects and represents the in-group, while undermining the credibility of the political rival. Study 4 is a qualitative study analysing counter-hegemonic discourse on mobilisations against the rhetoric of hatred. Taken together, the first 3 studies argue that hatred is not an inherent feature of individuals or a natural fall-out of inter-group processes, it is mobilised for specific political aims. The fourth study looks at the dimensions with which other leaders counteract the politics of hate; when hatred can be mobilised, so can solidarity. The theoretical implications and limitations have been discussed.
2016-11-30T00:00:00ZRath, RakshiThe aim of the thesis is to provide a social identity account of the politics of mobilisation: based on hatred mostly, in contrast with accounts of solidarity. The bulk of the thesis concentrates on exploring how and why is prejudice in the form of hatred mobilised in inter-group relations. Three studies parse the structure of hate discourse of Hindu right-wing groups in India. Study 1 and study 2 are qualitative studies that analyse the production of hate in two mediums of communication, while study 3 is an experimental study demonstrating the reception of hate. The studies analyse the structure of hate discourse with the theoretical lens of a social identity framework to explicate a context of categories and category-relations, while colouring in the contents of the categories with data from India. The first contention is, if a virtuous in-group can be construed as under threat from an out-group, then, the annihilation of the other can be justified as the defence of virtue. In the other words, violence becomes virtuous. The second contention is, the process that motivates out-group hate discourse derives from struggles over intra-group authority. That is, out-group threats are invoked in order to condemn political rivals for in-group power as not representing the group and not defending group interests. This sets up the foil for the leader to position ‘self’ as the ideal leader who protects and represents the in-group, while undermining the credibility of the political rival. Study 4 is a qualitative study analysing counter-hegemonic discourse on mobilisations against the rhetoric of hatred. Taken together, the first 3 studies argue that hatred is not an inherent feature of individuals or a natural fall-out of inter-group processes, it is mobilised for specific political aims. The fourth study looks at the dimensions with which other leaders counteract the politics of hate; when hatred can be mobilised, so can solidarity. The theoretical implications and limitations have been discussed.Organic light-emitting diodes for optogenetic stimulation of Drosophila larvaeMurawski, CarolineMorton, AndrewSamuel, Ifor David WilliamPulver, StefanGather, Malte Christianhttps://hdl.handle.net/10023/98612024-03-02T00:39:41Z2016-11-14T00:00:00ZOptogenetics is an emerging method in biology that enables controlling neurons with light. We use organic light-emitting diodes to stimulate neurons in Drosophila larvae and investigate subsequent behavioral changes at different light intensities.
We are grateful for financial support from the Scottish Funding Council (through SUPA), Human Frontier Science Program (RGY0074/2013), Wellcome Trust Institutional Strategic Support Fund St Andrews, the RS Macdonald Charitable Trust, and EPSRC via grant EP/J01771X/1. CM acknowledges funding by the European Commission through a Marie Skłodowska Curie individual fellowship (703387).
2016-11-14T00:00:00ZMurawski, CarolineMorton, AndrewSamuel, Ifor David WilliamPulver, StefanGather, Malte ChristianOptogenetics is an emerging method in biology that enables controlling neurons with light. We use organic light-emitting diodes to stimulate neurons in Drosophila larvae and investigate subsequent behavioral changes at different light intensities.Evaluation and characterisation of two zebrafish models of schizophreniaDaggett, J. M. (Jenny Michelle)https://hdl.handle.net/10023/96032019-08-06T11:14:33Z2016-11-30T00:00:00ZCognitive deficits are the single strongest predictor of the functional outcome in patients with schizophrenia. Current treatments are largely ineffective in improving cognitive impairments and promising pre-clinical research has mostly failed to translate clinically. Despite the advances provided by rodent models, the neurobiological basis of cognitive deficits in schizophrenia is poorly understood. Therefore, this thesis proposes a zebrafish model for studying cognitive impairments of schizophrenia.
Although more evolutionarily distant to humans compared to the rat, the zebrafish has emerged as a popular vertebrate model of human disorders due to its genetic tractability, complex nervous system and elaborate behavioural repertoire. We investigated the effects of genetic alterations and neurodevelopmental disruption on behaviour and learning in zebrafish. Using both disc1 mutant lines and sub-chronic phencyclidine (PCP) on larvae from 6-10 dpf, we were able to assess behavioural changes as a function of developmental age.
In particular, this thesis aimed to develop appropriate behavioural assays to assess zebrafish learning and executive function relevant to disorders seen in human patients with schizophrenia. It was possible to demonstrate robust learning across several domains, namely, reversal, classical avoidance and non-associative learning, alongside locomotor and anxiety-related behaviours. There were varied deficits associated with each of the two – genetic (disc1 gene mutation) and environmental (sub-chronic PCP) – manipulations, consistent with observations in rat research.
Together, the research in this thesis demonstrates that a zebrafish model exhibits behaviour resembling that of mammalian models of schizophrenia and provides a foundation for the utility of zebrafish in examining cognitive impairments associated with schizophrenia.
2016-11-30T00:00:00ZDaggett, J. M. (Jenny Michelle)Cognitive deficits are the single strongest predictor of the functional outcome in patients with schizophrenia. Current treatments are largely ineffective in improving cognitive impairments and promising pre-clinical research has mostly failed to translate clinically. Despite the advances provided by rodent models, the neurobiological basis of cognitive deficits in schizophrenia is poorly understood. Therefore, this thesis proposes a zebrafish model for studying cognitive impairments of schizophrenia.
Although more evolutionarily distant to humans compared to the rat, the zebrafish has emerged as a popular vertebrate model of human disorders due to its genetic tractability, complex nervous system and elaborate behavioural repertoire. We investigated the effects of genetic alterations and neurodevelopmental disruption on behaviour and learning in zebrafish. Using both disc1 mutant lines and sub-chronic phencyclidine (PCP) on larvae from 6-10 dpf, we were able to assess behavioural changes as a function of developmental age.
In particular, this thesis aimed to develop appropriate behavioural assays to assess zebrafish learning and executive function relevant to disorders seen in human patients with schizophrenia. It was possible to demonstrate robust learning across several domains, namely, reversal, classical avoidance and non-associative learning, alongside locomotor and anxiety-related behaviours. There were varied deficits associated with each of the two – genetic (disc1 gene mutation) and environmental (sub-chronic PCP) – manipulations, consistent with observations in rat research.
Together, the research in this thesis demonstrates that a zebrafish model exhibits behaviour resembling that of mammalian models of schizophrenia and provides a foundation for the utility of zebrafish in examining cognitive impairments associated with schizophrenia.Visuo-spatial working memoryRalston, George Eastophttps://hdl.handle.net/10023/95952019-04-01T10:41:37Z1988-01-01T00:00:00ZThis study set out to investigate the visuo-spatial component of
Baddeley and Hitch's (1974) Working Memory framework. The development
of our understanding of this component has been less dramatic than
that of its verbal counterpart, the Articulatory Loop. The primary
reason for this can be said to be the lack of techniques for
investigation (Logie, 1986). This thesis presents one attempt to try
to explore the nature of this code and to reveal possible new
techniques of investigation. The following are three possible areas
of investigation :
1. Is the system spatially or visually based?
2. Does movement have a role in the system?
3. How is information stored?
The latter two issues are investigated here. Experiments 1-4 set
out to explore the possibility that movement may be involved in the
code. These experiments supported the idea that movement has a role
to play in spatial coding and more specifically demonstrated that arm
movements which are not compatible with the presentation of spatial
material can cause disruption. In addition it was shown that when
movement identical to that involved in presentation is encouraged at
recall subjects show marked improvement in performance. Together
these results very strongly suggest that movement should be given
prominent reference in the definition of spatial coding and in the
description of the visuo-spatial slave system.
Another development that came out of these experiments relates to
the lack of investigative techniques in the field of visuo-spatial
short term memory. The fact that movement has been shown to be
important suggests that techniques employed to investigate
kinaesthetic memory will aid us in exploring visuo-spatial coding.
The second issue in this thesis explored further the nature of
the internal code. Research into the nature of coding in
visuo-spatial memory had previously argued for the presence of a
sequential component. Experiments 1-4 in this thesis had shown that
movement had an important role to play in coding. The fact that
movement by its very nature would appear to be sequential suggested
that there was a strong sequential element in coding within
visuo-spatial memory. However, concern was expressed that the
materials and presentation format used may have led to sequential
coding. This was first explored in experiments 5-8. The results
supported the view that the material and presentation format used had
led to sequential coding. This was further explored by Experiments 9
and 10 which illustrated that while it may be important under certain
conditions, sequentiality is not always a dominant element in coding
within the Visuo-Spatial Sketch Pad.
This thesis has explored two of the central issues currently
interesting theorists of Working Memory and has put forward
suggestions for techniques which may in the future help us to advance
our knowledge of the visuo-spatial component of the Working Memory
framework.
1988-01-01T00:00:00ZRalston, George EastopThis study set out to investigate the visuo-spatial component of
Baddeley and Hitch's (1974) Working Memory framework. The development
of our understanding of this component has been less dramatic than
that of its verbal counterpart, the Articulatory Loop. The primary
reason for this can be said to be the lack of techniques for
investigation (Logie, 1986). This thesis presents one attempt to try
to explore the nature of this code and to reveal possible new
techniques of investigation. The following are three possible areas
of investigation :
1. Is the system spatially or visually based?
2. Does movement have a role in the system?
3. How is information stored?
The latter two issues are investigated here. Experiments 1-4 set
out to explore the possibility that movement may be involved in the
code. These experiments supported the idea that movement has a role
to play in spatial coding and more specifically demonstrated that arm
movements which are not compatible with the presentation of spatial
material can cause disruption. In addition it was shown that when
movement identical to that involved in presentation is encouraged at
recall subjects show marked improvement in performance. Together
these results very strongly suggest that movement should be given
prominent reference in the definition of spatial coding and in the
description of the visuo-spatial slave system.
Another development that came out of these experiments relates to
the lack of investigative techniques in the field of visuo-spatial
short term memory. The fact that movement has been shown to be
important suggests that techniques employed to investigate
kinaesthetic memory will aid us in exploring visuo-spatial coding.
The second issue in this thesis explored further the nature of
the internal code. Research into the nature of coding in
visuo-spatial memory had previously argued for the presence of a
sequential component. Experiments 1-4 in this thesis had shown that
movement had an important role to play in coding. The fact that
movement by its very nature would appear to be sequential suggested
that there was a strong sequential element in coding within
visuo-spatial memory. However, concern was expressed that the
materials and presentation format used may have led to sequential
coding. This was first explored in experiments 5-8. The results
supported the view that the material and presentation format used had
led to sequential coding. This was further explored by Experiments 9
and 10 which illustrated that while it may be important under certain
conditions, sequentiality is not always a dominant element in coding
within the Visuo-Spatial Sketch Pad.
This thesis has explored two of the central issues currently
interesting theorists of Working Memory and has put forward
suggestions for techniques which may in the future help us to advance
our knowledge of the visuo-spatial component of the Working Memory
framework.Detecting a visual object in the presence of other objects : the flanker facilitation effect in contour integrationGillespie, Christopherhttps://hdl.handle.net/10023/94792019-04-01T10:40:08Z2015-01-01T00:00:00ZWhen an observer views a complex visual scene and tries to identify an object, his
or her visual system must decide what regions of the visual field correspond to the
object of interest and which do not. One aspect of this process involves the grouping of the local contrast information (e.g., orientation, position and frequency) into
a smooth contour object. This thesis investigated whether the presence of other
flanking objects affected this contour integration of a central target contour.
To test this, a set of Gaborized contour shapes were embedded in a randomised
Gabor noise field. The detectability of the contours was altered by adjusting the
alignment of the Gabor patches in the contour (orientation jitter) until a participant
was unable to distinguish between a field with and without a target shape (2-AFC
procedure). By varying the magnitude of this jitter, detection thresholds were determined for target contours under various experimental conditions. These thresholds
were used to investigate whether contour integration was sensitive to shared shape
information between objects across the visual field.
This thesis determined that the presence of flanking contours of a similar shape
(as the target) facilitated the detection of a noisy target contour. The specific results suggest that this facilitation does not involve a simple template matching or
shape priming but is associated with integration of shape level information in the
detection of the most likely smooth closed contour. The magnitude of this flanker
facilitation effect was sensitive to a number of factors (e.g., numerosity, relative
position of the flankers, and perimeter complexity/compactness). The implication
of these findings is that the processing of highly localised contrast and orientation
information originating from a single object is subject to modulation from other
sources of shape information across the whole of the visual field.
2015-01-01T00:00:00ZGillespie, ChristopherWhen an observer views a complex visual scene and tries to identify an object, his
or her visual system must decide what regions of the visual field correspond to the
object of interest and which do not. One aspect of this process involves the grouping of the local contrast information (e.g., orientation, position and frequency) into
a smooth contour object. This thesis investigated whether the presence of other
flanking objects affected this contour integration of a central target contour.
To test this, a set of Gaborized contour shapes were embedded in a randomised
Gabor noise field. The detectability of the contours was altered by adjusting the
alignment of the Gabor patches in the contour (orientation jitter) until a participant
was unable to distinguish between a field with and without a target shape (2-AFC
procedure). By varying the magnitude of this jitter, detection thresholds were determined for target contours under various experimental conditions. These thresholds
were used to investigate whether contour integration was sensitive to shared shape
information between objects across the visual field.
This thesis determined that the presence of flanking contours of a similar shape
(as the target) facilitated the detection of a noisy target contour. The specific results suggest that this facilitation does not involve a simple template matching or
shape priming but is associated with integration of shape level information in the
detection of the most likely smooth closed contour. The magnitude of this flanker
facilitation effect was sensitive to a number of factors (e.g., numerosity, relative
position of the flankers, and perimeter complexity/compactness). The implication
of these findings is that the processing of highly localised contrast and orientation
information originating from a single object is subject to modulation from other
sources of shape information across the whole of the visual field.Computerized self-administered measures of mood and appetite for older adults : the Novel Assessment of Nutrition and Ageing toolkitBrown, Laura J EAdlam, TimHwang, FaustinaKhadra, HassanMaclean, Linda MRudd, BrideySmith, TomTimon, ClaireWilliams, Elizabeth AAstell, Arlene Jhttps://hdl.handle.net/10023/93512024-02-17T00:41:30Z2016-02-10T00:00:00ZThe "Novel Assessment of Nutrition and Ageing" (NANA) toolkit is a computerized system for collecting longitudinal information about older adults' health and behavior. Here, we describe the validation of six items for measuring older adults' self-reported mood and appetite as part of the NANA system. In Study 1, 48 community-living older adults (aged 65-89 years) completed NANA measures of their current mood and appetite alongside standard paper measures, on three occasions, in a laboratory setting. In Study 2, 40 community-living older adults (aged 64-88 years) completed daily NANA measures of momentary mood and appetite in their own homes, unsupervised, alongside additional measures of health and behavior, over three 7-day periods. The NANA measures were significantly correlated with standard measures of mood and appetite, and showed stability over time. They show utility for tracking mood and appetite longitudinally, and for better understanding links with other aspects of health and behavior.
This work was supported by Grant ES/G008779/1 awarded to A.J.A., T.A., F.H., and E.A.W. from the New Dynamics of Ageing (NDA) Programme. The funding partners of the NDA are Economic and Social Research Council (ESRC), Engineering and Physical Sciences Research Council (EPSRC), Biotechnology and Biological Sciences Research Council (BBSRC), Medical Research Council (MRC), and Arts and Humanities Research Council.
2016-02-10T00:00:00ZBrown, Laura J EAdlam, TimHwang, FaustinaKhadra, HassanMaclean, Linda MRudd, BrideySmith, TomTimon, ClaireWilliams, Elizabeth AAstell, Arlene JThe "Novel Assessment of Nutrition and Ageing" (NANA) toolkit is a computerized system for collecting longitudinal information about older adults' health and behavior. Here, we describe the validation of six items for measuring older adults' self-reported mood and appetite as part of the NANA system. In Study 1, 48 community-living older adults (aged 65-89 years) completed NANA measures of their current mood and appetite alongside standard paper measures, on three occasions, in a laboratory setting. In Study 2, 40 community-living older adults (aged 64-88 years) completed daily NANA measures of momentary mood and appetite in their own homes, unsupervised, alongside additional measures of health and behavior, over three 7-day periods. The NANA measures were significantly correlated with standard measures of mood and appetite, and showed stability over time. They show utility for tracking mood and appetite longitudinally, and for better understanding links with other aspects of health and behavior.A neuroeconomic investigation of risky decision-making and loss in the ratWheeler Huttunen, Annamariehttps://hdl.handle.net/10023/93312019-04-01T10:42:21Z2016-06-01T00:00:00ZHumans exhibit a number of suboptimal behaviours in the wake of a loss. For
example, gamblers often ‘chase’ their losses in an attempt to break even.
Similarly, investors tend to hold on to losing stocks too long in the hope that the
declining share price might make a recovery. However, the neural mechanisms
that instantiate such behaviour are poorly understood. I begin the introductory
chapter with a basic historical overview of fundamental economic concepts,
interleaving intersecting ideas from psychology and neuroscience. This leads to
a more in-depth exploration of the notion that loss-related behavioural biases
might provide insight into the neural mechanisms that underlie risky choice.
From this, I argue that rats represent a viable animal model of risky decision-
making for neuroeconomic research. The original research presented in
Chapters 2 – 5 pave the way toward advancing our current understanding of
loss-related biases in behaviour with rat models of risky decision-making. By
employing insight from psychology and economics, I developed two models of
rat behaviour that can be used to study the neural substrates of loss valuation. I
presented the experimental paradigms in Chapters 2 and 5, while
demonstrating novel loss-related correlations between the midbrain dopamine
system and observed loss behaviour in Chapters 3 and 4. The results
presented in Chapter 5 demonstrate that rats are capable of producing
behavioural patterns akin to loss aversion and the disposition effect. This work
has also highlighted a number of areas for future research. In Chapter 6, I
explore potential theoretical implications of the results discussed in previous
chapters. In summary, this thesis uses experimental risky decision-making
tasks in rats to advance our current knowledge of the ways in which concepts
such as loss aversion critically influence our internal representation of value.
2016-06-01T00:00:00ZWheeler Huttunen, AnnamarieHumans exhibit a number of suboptimal behaviours in the wake of a loss. For
example, gamblers often ‘chase’ their losses in an attempt to break even.
Similarly, investors tend to hold on to losing stocks too long in the hope that the
declining share price might make a recovery. However, the neural mechanisms
that instantiate such behaviour are poorly understood. I begin the introductory
chapter with a basic historical overview of fundamental economic concepts,
interleaving intersecting ideas from psychology and neuroscience. This leads to
a more in-depth exploration of the notion that loss-related behavioural biases
might provide insight into the neural mechanisms that underlie risky choice.
From this, I argue that rats represent a viable animal model of risky decision-
making for neuroeconomic research. The original research presented in
Chapters 2 – 5 pave the way toward advancing our current understanding of
loss-related biases in behaviour with rat models of risky decision-making. By
employing insight from psychology and economics, I developed two models of
rat behaviour that can be used to study the neural substrates of loss valuation. I
presented the experimental paradigms in Chapters 2 and 5, while
demonstrating novel loss-related correlations between the midbrain dopamine
system and observed loss behaviour in Chapters 3 and 4. The results
presented in Chapter 5 demonstrate that rats are capable of producing
behavioural patterns akin to loss aversion and the disposition effect. This work
has also highlighted a number of areas for future research. In Chapter 6, I
explore potential theoretical implications of the results discussed in previous
chapters. In summary, this thesis uses experimental risky decision-making
tasks in rats to advance our current knowledge of the ways in which concepts
such as loss aversion critically influence our internal representation of value.Understanding object-directed intentionality in Capuchin monkeys and humansTao, Ruotinghttps://hdl.handle.net/10023/93042019-04-01T10:41:59Z2016-06-01T00:00:00ZUnderstanding intentionality, i.e. coding the object directedness of agents
towards objects, is a fundamental component of Theory of Mind abilities. Yet it is
unclear how it is perceived and coded in different species. In this thesis, we present
a series of comparative studies to explore human adults’ and Capuchin monkeys’
ability to infer intentional objects from actions.
First we studied whether capuchin monkeys and adult humans infer a potential
object from observing an object-directed action. With no direct information about
the goal-object, neither species inferred the object from the action. However, when
the object was revealed, the monkeys retrospectively encoded the directedness of
the object-directed action; unexpectedly, in an adapted version of the task adult
humans did not show a similar ability.
We then adapted another paradigm, originally designed by Kovács et al (2010),
to examine whether the two species implicitly register the intentional relation
between an agent and an object. We manipulated an animated agent and the
participants’ belief about a ball’s presence behind a hiding screen. We found no
evidence showing that humans or monkeys coded object-directedness or belief.
More importantly, we failed to replicate the original results from Kovács et al’s study,
and through a series of follow up studies, we questioned their conclusions regarding
implicit ToM understanding. We suggested that, instead of implicit ToM, results like
Kovacs et al’s might be interpreted as driven by “sub-mentalizing” processes, as
suggested by Heyes (2014).
We conclude that so called ‘implicit ToM’ may be based upon the computation
of intentional relations between perceived agents and objects. But, these
computations might present limitations, and some results attributed to implicit ToM
may in fact reflect “sub-mentalizing” processes.
2016-06-01T00:00:00ZTao, RuotingUnderstanding intentionality, i.e. coding the object directedness of agents
towards objects, is a fundamental component of Theory of Mind abilities. Yet it is
unclear how it is perceived and coded in different species. In this thesis, we present
a series of comparative studies to explore human adults’ and Capuchin monkeys’
ability to infer intentional objects from actions.
First we studied whether capuchin monkeys and adult humans infer a potential
object from observing an object-directed action. With no direct information about
the goal-object, neither species inferred the object from the action. However, when
the object was revealed, the monkeys retrospectively encoded the directedness of
the object-directed action; unexpectedly, in an adapted version of the task adult
humans did not show a similar ability.
We then adapted another paradigm, originally designed by Kovács et al (2010),
to examine whether the two species implicitly register the intentional relation
between an agent and an object. We manipulated an animated agent and the
participants’ belief about a ball’s presence behind a hiding screen. We found no
evidence showing that humans or monkeys coded object-directedness or belief.
More importantly, we failed to replicate the original results from Kovács et al’s study,
and through a series of follow up studies, we questioned their conclusions regarding
implicit ToM understanding. We suggested that, instead of implicit ToM, results like
Kovacs et al’s might be interpreted as driven by “sub-mentalizing” processes, as
suggested by Heyes (2014).
We conclude that so called ‘implicit ToM’ may be based upon the computation
of intentional relations between perceived agents and objects. But, these
computations might present limitations, and some results attributed to implicit ToM
may in fact reflect “sub-mentalizing” processes.An evaluation of cognitive deficits in a rat-model of Huntington's diseaseGarcía Aguirre, Ana I.https://hdl.handle.net/10023/88272019-04-01T10:41:38Z2016-06-21T00:00:00ZThe purpose of this thesis was to develop methodology by which treatments for the cognitive impairments in Huntington’s disease (HD) could be tested. As such, the thesis focused mainly on evaluating rats with quinolinic acid (QA) lesions of the striatum, as this manipulation mimics some aspects of the neural damage in Huntington’s disease, to try to identify cognitive deficits of HD resulting from cell loss in the striatum.
In the first part (Chapters 3-5), the role of the striatum in implicit memory was investigated. Chapter 3 compared the performance of rats and humans on a reaction time task that evaluated implicit memory by presenting visual stimuli with differing probabilities which change over time. Although rats made higher percentage of incorrect responses and late errors, both groups showed a similar pattern of reaction times. Chapter 4 investigated whether implicit memory (the computation of probabilities to predict the location of a stimulus) was affected by selective blockade of dopaminergic transmission at the D1 or D2 receptors by SCH-23390 and raclopride, respectively. Reaction times were slower with SCH-23390 and raclopride, but only SCH-23390 reduced errors to the least probable target location. Chapter 5 used the same task to evaluate implicit memory in rats with QA lesions of the dorsomedial striatum (DMS). Implicit memory was not affected by lesions of the DMS, which suggested that once a task that requires implicit memory has been learned, the DMS was not involved in sustaining the performance of the task. The second part of this thesis (Chapter 6), explored the contribution of the DMS in habit formation. DMS lesioned rats did not show habitual responding, and were not impaired in learning a new goal-directed behaviour. The third part (Chapters 7 and 8), investigated the role of the dorsal striatum in reversal learning, attentional set-formation, and set-shifting. Dorsal striatum lesioned rats were not impaired in reversal learning, but had a diminished shift-cost, which suggested that dorsal striatum lesions disrupted the formation of attentional sets.
These results showed that although QA lesions of the dorsal striatum mimic some aspects of the neural damage in HD, they did not result in the same cognitive deficits observed in patients with HD, at least using the tasks presented in this thesis. However, other animal models of HD could be evaluated using the different tasks presented in this thesis to continue the search of a reliable animal model of HD in which treatments for the disease could be evaluated.
2016-06-21T00:00:00ZGarcía Aguirre, Ana I.The purpose of this thesis was to develop methodology by which treatments for the cognitive impairments in Huntington’s disease (HD) could be tested. As such, the thesis focused mainly on evaluating rats with quinolinic acid (QA) lesions of the striatum, as this manipulation mimics some aspects of the neural damage in Huntington’s disease, to try to identify cognitive deficits of HD resulting from cell loss in the striatum.
In the first part (Chapters 3-5), the role of the striatum in implicit memory was investigated. Chapter 3 compared the performance of rats and humans on a reaction time task that evaluated implicit memory by presenting visual stimuli with differing probabilities which change over time. Although rats made higher percentage of incorrect responses and late errors, both groups showed a similar pattern of reaction times. Chapter 4 investigated whether implicit memory (the computation of probabilities to predict the location of a stimulus) was affected by selective blockade of dopaminergic transmission at the D1 or D2 receptors by SCH-23390 and raclopride, respectively. Reaction times were slower with SCH-23390 and raclopride, but only SCH-23390 reduced errors to the least probable target location. Chapter 5 used the same task to evaluate implicit memory in rats with QA lesions of the dorsomedial striatum (DMS). Implicit memory was not affected by lesions of the DMS, which suggested that once a task that requires implicit memory has been learned, the DMS was not involved in sustaining the performance of the task. The second part of this thesis (Chapter 6), explored the contribution of the DMS in habit formation. DMS lesioned rats did not show habitual responding, and were not impaired in learning a new goal-directed behaviour. The third part (Chapters 7 and 8), investigated the role of the dorsal striatum in reversal learning, attentional set-formation, and set-shifting. Dorsal striatum lesioned rats were not impaired in reversal learning, but had a diminished shift-cost, which suggested that dorsal striatum lesions disrupted the formation of attentional sets.
These results showed that although QA lesions of the dorsal striatum mimic some aspects of the neural damage in HD, they did not result in the same cognitive deficits observed in patients with HD, at least using the tasks presented in this thesis. However, other animal models of HD could be evaluated using the different tasks presented in this thesis to continue the search of a reliable animal model of HD in which treatments for the disease could be evaluated.Purinergic and cholinergic modulation of spinal motor networks in miceWitts, Emilyhttps://hdl.handle.net/10023/85132019-04-01T10:40:33Z2016-06-21T00:00:00ZNeuromodulation allows flexibility within networks of neurons controlling rhythmic motor behaviours. This thesis explores how purinergic and cholinergic neuromodulation contributes to the functioning of spinal motor networks in mice.
Purinergic modulation in the spinal cord was investigated using neonatal mouse in vitro spinal cord preparations in which locomotor-related bursts of activity were pharmacologically induced. Ventral root recordings from these preparations showed that glia release ATP, which is broken down to adenosine and binds to A1 adenosine receptors to reduce the frequency of locomotor-related bursts. Whole-cell patch-clamp recordings showed that adenosine opens leak potassium channels in ventral horn interneurons, leading to general network inhibition. Interestingly, although adenosine reduces synaptic inputs in interneurons and motoneurons, interneurons show a reversible hyperpolarisation and reduction of miniature postsynaptic currents (mPSCs) in response to adenosine, while motoneurons show a reversible depolarisation and no change in mPSCs. It was therefore concluded that adenosine opens leak potassium channels in ventral horn interneurons which reduces the speed of locomotor-related output from the whole network. However, motoneuron activity is prevented from falling so far as to cause muscle contraction to cease.
Cholinergic modulation of mouse spinal motor networks was also investigated. Pitx2+ cells, known to be the source of cholinergic C-bouton inputs to motoneurons, were selectively transfected with channelrhodopsin and light was used to activate the Pitx2+ cell population. Pitx2+ cell activation was found to reduce rheobase and range of firing in small numbers of spinal motoneurons. The role of Pitx2+ cells in behaviour was also investigated by testing adult mice before and after Pitx2+ cell ablation. No difference in performance was observed in reaching or ladder walking tasks. It therefore seems likely that activation of Pitx2+ cells modulates motoneurons via C bouton synapses, but this modulation is task-dependent and is not critical for goal-directed movements requiring fine motor control.
2016-06-21T00:00:00ZWitts, EmilyNeuromodulation allows flexibility within networks of neurons controlling rhythmic motor behaviours. This thesis explores how purinergic and cholinergic neuromodulation contributes to the functioning of spinal motor networks in mice.
Purinergic modulation in the spinal cord was investigated using neonatal mouse in vitro spinal cord preparations in which locomotor-related bursts of activity were pharmacologically induced. Ventral root recordings from these preparations showed that glia release ATP, which is broken down to adenosine and binds to A1 adenosine receptors to reduce the frequency of locomotor-related bursts. Whole-cell patch-clamp recordings showed that adenosine opens leak potassium channels in ventral horn interneurons, leading to general network inhibition. Interestingly, although adenosine reduces synaptic inputs in interneurons and motoneurons, interneurons show a reversible hyperpolarisation and reduction of miniature postsynaptic currents (mPSCs) in response to adenosine, while motoneurons show a reversible depolarisation and no change in mPSCs. It was therefore concluded that adenosine opens leak potassium channels in ventral horn interneurons which reduces the speed of locomotor-related output from the whole network. However, motoneuron activity is prevented from falling so far as to cause muscle contraction to cease.
Cholinergic modulation of mouse spinal motor networks was also investigated. Pitx2+ cells, known to be the source of cholinergic C-bouton inputs to motoneurons, were selectively transfected with channelrhodopsin and light was used to activate the Pitx2+ cell population. Pitx2+ cell activation was found to reduce rheobase and range of firing in small numbers of spinal motoneurons. The role of Pitx2+ cells in behaviour was also investigated by testing adult mice before and after Pitx2+ cell ablation. No difference in performance was observed in reaching or ladder walking tasks. It therefore seems likely that activation of Pitx2+ cells modulates motoneurons via C bouton synapses, but this modulation is task-dependent and is not critical for goal-directed movements requiring fine motor control.Light activated escape circuits : a behavior and neurophysiology lab module using Drosophila optogeneticsTitlow, Joshua S.Johnson, Bruce R.Pulver, Stefan R.https://hdl.handle.net/10023/82562024-03-21T00:41:46Z2015-07-07T00:00:00ZThe neural networks that control escape from predators often show very clear relationships between defined sensory inputs and stereotyped motor outputs. This feature provides unique opportunities for researchers, but it also provides novel opportunities for neuroscience educators. Here we introduce new teaching modules using adult Drosophila that have been engineered to express csChrimson, a red-light sensitive channelrhodopsin, in specific sets of neurons and muscles mediating visually guided escape behaviors. This lab module consists of both behavior and electrophysiology experiments that explore the neural basis of flight escape. Three preparations are described that demonstrate photo-activation of the giant fiber circuit and how to quantify these behaviors. One of the preparations is then used to acquire intracellular electrophysiology recordings from different flight muscles. The diversity of action potential waveforms and firing frequencies observed in the flight muscles make this a rich preparation to study the ionic basic of cellular excitability. By activating different cells within the giant fiber pathway we also demonstrate principles of synaptic transmission and neural circuits. Beyond conveying core neurobiological concepts it is also expected that using these cutting edge techniques will enhance student motivation and attitudes towards biological research. Data collected from students and educators who have been involved in development of the module are presented to support this notion.
2015-07-07T00:00:00ZTitlow, Joshua S.Johnson, Bruce R.Pulver, Stefan R.The neural networks that control escape from predators often show very clear relationships between defined sensory inputs and stereotyped motor outputs. This feature provides unique opportunities for researchers, but it also provides novel opportunities for neuroscience educators. Here we introduce new teaching modules using adult Drosophila that have been engineered to express csChrimson, a red-light sensitive channelrhodopsin, in specific sets of neurons and muscles mediating visually guided escape behaviors. This lab module consists of both behavior and electrophysiology experiments that explore the neural basis of flight escape. Three preparations are described that demonstrate photo-activation of the giant fiber circuit and how to quantify these behaviors. One of the preparations is then used to acquire intracellular electrophysiology recordings from different flight muscles. The diversity of action potential waveforms and firing frequencies observed in the flight muscles make this a rich preparation to study the ionic basic of cellular excitability. By activating different cells within the giant fiber pathway we also demonstrate principles of synaptic transmission and neural circuits. Beyond conveying core neurobiological concepts it is also expected that using these cutting edge techniques will enhance student motivation and attitudes towards biological research. Data collected from students and educators who have been involved in development of the module are presented to support this notion.Social life and flexibility of vocal behaviour in Diana monkeys and other cercopithecidsCandiotti, Agnèshttps://hdl.handle.net/10023/81712019-04-01T10:41:18Z2013-01-01T00:00:00ZRecent studies on the social life and vocal production, usage and comprehension of nonhuman primates have brought new insights into the evolutionary mechanisms of cognition and communication as well as the emergence of language. A key point in the current literature concerns the flexibility of vocal production. In contrast to humans, some birds and some cetaceans, vocal flexibility is thought to be very restricted in nonhuman primates, which creates a startling phylogenetic gap. At the same time, research has shown that a number of African forest guenons’ alarm calls appear to have language-like properties. With the hypothesis that looking at the vocal repertoire more broadly, especially the social calls, was likely to reveal other complex communicative abilities, I studied in detail the social life and vocal behaviour of a guenon species, Diana monkeys. First, the comparison of its social system with the system of another closely related species, Campbell’s monkeys, stressed in both species the reduced number of physical interactions, although females maintained preferential relationships that were not biased towards kin. Second, the study of Diana females’ vocal repertoire is restricted but flexible. Females emit social calls with a combinatorial structure, the use of which is affected by external events. Third, focusing on a highly frequent and highly social call revealed flexibility in the identity advertisement (divergence – convergence) which accommodates to the context. Fourth, to explore the nature of nonhuman primates’ comprehension skills, I performed playback experiments of De Brazza monkey social calls to three species of Old World monkeys; Campbell’s monkeys, black-and-white colobus monkeys and red-capped mangabeys. Altogether, the three species were able to discriminate hetero-specific voices of individuals they knew from individuals they had never met. Overall, my results have revealed a considerable degree of flexibility in the vocal communication of nonhuman primates, a finding that is consistent with the hypothesis of a continuous evolutionary transition from animal vocal behaviour to human language.
Electronic version does not contain associated previously published material
2013-01-01T00:00:00ZCandiotti, AgnèsRecent studies on the social life and vocal production, usage and comprehension of nonhuman primates have brought new insights into the evolutionary mechanisms of cognition and communication as well as the emergence of language. A key point in the current literature concerns the flexibility of vocal production. In contrast to humans, some birds and some cetaceans, vocal flexibility is thought to be very restricted in nonhuman primates, which creates a startling phylogenetic gap. At the same time, research has shown that a number of African forest guenons’ alarm calls appear to have language-like properties. With the hypothesis that looking at the vocal repertoire more broadly, especially the social calls, was likely to reveal other complex communicative abilities, I studied in detail the social life and vocal behaviour of a guenon species, Diana monkeys. First, the comparison of its social system with the system of another closely related species, Campbell’s monkeys, stressed in both species the reduced number of physical interactions, although females maintained preferential relationships that were not biased towards kin. Second, the study of Diana females’ vocal repertoire is restricted but flexible. Females emit social calls with a combinatorial structure, the use of which is affected by external events. Third, focusing on a highly frequent and highly social call revealed flexibility in the identity advertisement (divergence – convergence) which accommodates to the context. Fourth, to explore the nature of nonhuman primates’ comprehension skills, I performed playback experiments of De Brazza monkey social calls to three species of Old World monkeys; Campbell’s monkeys, black-and-white colobus monkeys and red-capped mangabeys. Altogether, the three species were able to discriminate hetero-specific voices of individuals they knew from individuals they had never met. Overall, my results have revealed a considerable degree of flexibility in the vocal communication of nonhuman primates, a finding that is consistent with the hypothesis of a continuous evolutionary transition from animal vocal behaviour to human language.Experiences of young adult Muslim second generation immigrants in Britain : beyond acculturationAshraf, Mujeebahttps://hdl.handle.net/10023/80992022-08-31T02:02:59Z2016-06-21T00:00:00ZThis research is an attempt to understand the living experiences of young adult Muslim SGIs, in Britain. This research advocates to understand their living experiences from the perspective of social identity approach which discusses multiple dimensions of identity, unlike acculturation theory which focuses on a mono dimension of identity. This research introduced a multiple social identity model for Muslim SGIs. Contrary to the previous literature, the first study, the interview study, revealed that they explained their conflicts with their non-Muslim British peers and with their parents on the basis of non-shared identity. With their non-Muslim British peers they shared cultural (national) identity, therefore, they explained their conflicts in terms of different religious values (practices); with their parents they shared religious identity, therefore they explained their conflicts in terms of different cultural (ethnic) values and practices. They argued that their parents practise various cultural practices in the name of Islam, and Muslim SGIs distinguished Islam from their parents’ culture, and identified with the former, not the latter, and attributed their conflicts to their parents’ cultural values. In addition, they explained that their religious identity enables them to deal with conflicts with peers and parents. The second study, the focus group, successfully validated the findings of the first study, and it broadened the understanding of the fact that SGIs and their parents both explained their religion in their own cultural context. Their religious (Muslim) identity also promotes their relationships with their non-Muslim British peers and parents, which contributes positively towards their British identity, and more specifically they define themselves as British Muslims. In the third study, the survey study, the hypotheses were developed on the bases of the qualitative studies. It was expected and found that British and Muslim identities were positively correlated; they had non-significant identity differences with the Muslim identity and significant identity difference with British and ethnic identities from their parents. Ethnic identity difference from their parents was the only found predictor of their attribution of their conflicts to their parents’ cultural values.
2016-06-21T00:00:00ZAshraf, MujeebaThis research is an attempt to understand the living experiences of young adult Muslim SGIs, in Britain. This research advocates to understand their living experiences from the perspective of social identity approach which discusses multiple dimensions of identity, unlike acculturation theory which focuses on a mono dimension of identity. This research introduced a multiple social identity model for Muslim SGIs. Contrary to the previous literature, the first study, the interview study, revealed that they explained their conflicts with their non-Muslim British peers and with their parents on the basis of non-shared identity. With their non-Muslim British peers they shared cultural (national) identity, therefore, they explained their conflicts in terms of different religious values (practices); with their parents they shared religious identity, therefore they explained their conflicts in terms of different cultural (ethnic) values and practices. They argued that their parents practise various cultural practices in the name of Islam, and Muslim SGIs distinguished Islam from their parents’ culture, and identified with the former, not the latter, and attributed their conflicts to their parents’ cultural values. In addition, they explained that their religious identity enables them to deal with conflicts with peers and parents. The second study, the focus group, successfully validated the findings of the first study, and it broadened the understanding of the fact that SGIs and their parents both explained their religion in their own cultural context. Their religious (Muslim) identity also promotes their relationships with their non-Muslim British peers and parents, which contributes positively towards their British identity, and more specifically they define themselves as British Muslims. In the third study, the survey study, the hypotheses were developed on the bases of the qualitative studies. It was expected and found that British and Muslim identities were positively correlated; they had non-significant identity differences with the Muslim identity and significant identity difference with British and ethnic identities from their parents. Ethnic identity difference from their parents was the only found predictor of their attribution of their conflicts to their parents’ cultural values.Pupils' experiences of education : a study of pupils' viewsWarner, Suehttps://hdl.handle.net/10023/80052019-07-01T10:19:23Z1985-01-01T00:00:00ZThis thesis is primarily concerned with the experiences and opinions of education held by pupils in late secondary school and by university students. Over several years, a small group of highly able pupils were interviewed about their experiences of school and university. Their comments were supplemented by interviews with and questionnaire studies of other age-groups of pupils and students. The research has two central emphasises. Firstly, it represents an attempt to increase our understanding of intellectual development in adolescence. At present, there is no coherent theory of adolescent intellectual activity, and little research or evidence on which to build one. Pupil and student experiences of post-compulsory education have been central to this study and it is hoped that they will make a contribution to building up a body of knowledge on which understanding can be enhanced and a theory developed. The second, and related aspect of the research concerns educational practice and its influence on pupils and students. Educational changes are not made on the basis of solid evidence or theory, rather, they are based upon commonsense notions and our own experiences of education. In Scottish education, sixth year pupils face a radical change in the ways in which they are taught and expected to study - the Certificate of Sixth Year Studies (CSYS). Through independent study and project work, CSYS aims to increase the 'educational maturity' of pupils. Pupils' responses to CSYS, and its effects on how and why they study at school and university form the central focus of this thesis. The thesis examines in detail how pupils and students react to changes in their academic environment, both within school and transferring to university. Finally, the implications of the research are discussed in terms of adolescent development, educational innovation, and on a more basic level, how pupils, students, teachers and lecturers can better understand and improve the experience and effectiveness of post-compulsory education.
1985-01-01T00:00:00ZWarner, SueThis thesis is primarily concerned with the experiences and opinions of education held by pupils in late secondary school and by university students. Over several years, a small group of highly able pupils were interviewed about their experiences of school and university. Their comments were supplemented by interviews with and questionnaire studies of other age-groups of pupils and students. The research has two central emphasises. Firstly, it represents an attempt to increase our understanding of intellectual development in adolescence. At present, there is no coherent theory of adolescent intellectual activity, and little research or evidence on which to build one. Pupil and student experiences of post-compulsory education have been central to this study and it is hoped that they will make a contribution to building up a body of knowledge on which understanding can be enhanced and a theory developed. The second, and related aspect of the research concerns educational practice and its influence on pupils and students. Educational changes are not made on the basis of solid evidence or theory, rather, they are based upon commonsense notions and our own experiences of education. In Scottish education, sixth year pupils face a radical change in the ways in which they are taught and expected to study - the Certificate of Sixth Year Studies (CSYS). Through independent study and project work, CSYS aims to increase the 'educational maturity' of pupils. Pupils' responses to CSYS, and its effects on how and why they study at school and university form the central focus of this thesis. The thesis examines in detail how pupils and students react to changes in their academic environment, both within school and transferring to university. Finally, the implications of the research are discussed in terms of adolescent development, educational innovation, and on a more basic level, how pupils, students, teachers and lecturers can better understand and improve the experience and effectiveness of post-compulsory education.Data underpinning: Perception of Health from Facial CuesHenderson, Audrey J.Holzleitner, Iris J.Talamas, Sean N.Perrett, David I.https://hdl.handle.net/10023/79242016-07-11T14:11:34Z2015-12-01T00:00:00ZDataset handle is referred to in article available at http://dx.doi.org/10.1098/rstb.2015.0380
2015-12-01T00:00:00ZHenderson, Audrey J.Holzleitner, Iris J.Talamas, Sean N.Perrett, David I.Vision in-experience : investigating the interaction between the correct non-prototypical colours of colour diagnostic objects and object representation in human observersAdeyefa-Olasupo, Ifedayo-Emmanuelhttps://hdl.handle.net/10023/78632019-04-01T10:41:50Z2015-11-30T00:00:00ZHering (1964) hypothesized that the representation of a familiar object, which primarily includes its prototypical colour on the visual, conceptual and lexical domains may significantly influence how human observers organize the object’s chromatic attributes – hue, saturation and lightness. Over the past years, studies concerned with the perceptual nature these objects (e.g. Duncker, 1939; Hansen, Olkkonen, and Gegenfurtner, 2006; Witzel, Valkova, Hansen, and Gegenfurtner, 2011) have been able to demonstrate that the colour knowledge which is mentally represented for certain groups of familiar objects does in fact modulate colour perception in cases when human observers are instructed to recover the absolute hue of these objects. Studies have also found that the mental representation of these objects in certain conditions influences the colour perception of unfamiliar objects (Mitterer and Ruiter, 2008). However, it is still a mystery whether the correct non-prototypical colours associated with certain groups of familiar objects are included in the representation of these objects and as a result influence the observer’s ability to recover these objects’ typical hue and typical hue category. Thus, in this thesis, I investigated whether correct non-prototypical colours associated with a certain group of colour diagnostic objects, that is, frequently experienced colour diagnostic objects, influence the human observer’s ability to recover these objects’ typical hue and typical hue category. In order to identify colour diagnostic objects, that is, objects with a constant object-colour conjunction, in the first experiment, observers were presented a range of objects and instructed to select as fast and as accurately as they can the colour they would typically associate with the presented object under normal conditions. The accuracy rate and decision-time scores, which correspond to the conditions a given object must meet in order to be considered a colour diagnostic object, were recorded for each object (Biederman and Ju, 1988). After identifying a group of colour diagnostic objects, an experiential rating scale was implored, with six phenomenological descriptors assigned a numerical value from 0 to 5 with the lowest descriptor assigned an experiential value of 0 and the highest descriptor – always, assigned an experiential value of 5. Objects with high experiential value (≥4) were referred to as frequently experienced colour diagnostic objects while objects with low experiential value (<4) were referred to as infrequent colour diagnostic objects. In the main study, which included four conditions – colour neutral, name neutral, name Stroop, colour Stroop - I measured how quickly observers were able to select the typical hue or typical hue category of achromatic frequently experienced and infrequent colour diagnostic objects, using an object Stroop decision-time task. The object representation of the objects phenomenologically categorized as frequently experienced colour diagnostic objects includes not only the prototypical colour typically associated with these objects but also the correct non-prototypical colour these objects are commonly experienced in. As for the representation of the objects phenomenologically categorized as infrequent colour diagnostic objects, the object representation of these objects only includes their prototypical colour. For this reason, I hypothesized that for the frequently experienced colour diagnostic objects, observers should take longer to recover their typical hue and typical hue category due to these objects’ contextual associations which ultimately facilitates the mental activation of these objects’ correct non prototypical colour. On the other hand, for infrequent colour diagnostic objects observers would be quicker in recovering the objects’ typical hue and typical hue category as the activation of these objects’ colour is non-contextual, which therefore leads to the activation of a single colour. In one out of the four conditions, results for the object Stroop decision-time task demonstrated that observers on average took longer to recover the typical hue but not the typical hue category for the frequently experienced colour diagnostic objects when compared to the infrequent colour diagnostic objects. In general, results from this study support the idea that the object representations of colour diagnostic objects not only include their prototypical colour on multiple domains (Naor-Raz and Tarr, 2003), but that their correct non-prototypical colours may also may be represented on the conceptual and lexical domain, additional information human observers are able to use as they quickly attempt to recognize these objects in atypical perceptual conditions.
2015-11-30T00:00:00ZAdeyefa-Olasupo, Ifedayo-EmmanuelHering (1964) hypothesized that the representation of a familiar object, which primarily includes its prototypical colour on the visual, conceptual and lexical domains may significantly influence how human observers organize the object’s chromatic attributes – hue, saturation and lightness. Over the past years, studies concerned with the perceptual nature these objects (e.g. Duncker, 1939; Hansen, Olkkonen, and Gegenfurtner, 2006; Witzel, Valkova, Hansen, and Gegenfurtner, 2011) have been able to demonstrate that the colour knowledge which is mentally represented for certain groups of familiar objects does in fact modulate colour perception in cases when human observers are instructed to recover the absolute hue of these objects. Studies have also found that the mental representation of these objects in certain conditions influences the colour perception of unfamiliar objects (Mitterer and Ruiter, 2008). However, it is still a mystery whether the correct non-prototypical colours associated with certain groups of familiar objects are included in the representation of these objects and as a result influence the observer’s ability to recover these objects’ typical hue and typical hue category. Thus, in this thesis, I investigated whether correct non-prototypical colours associated with a certain group of colour diagnostic objects, that is, frequently experienced colour diagnostic objects, influence the human observer’s ability to recover these objects’ typical hue and typical hue category. In order to identify colour diagnostic objects, that is, objects with a constant object-colour conjunction, in the first experiment, observers were presented a range of objects and instructed to select as fast and as accurately as they can the colour they would typically associate with the presented object under normal conditions. The accuracy rate and decision-time scores, which correspond to the conditions a given object must meet in order to be considered a colour diagnostic object, were recorded for each object (Biederman and Ju, 1988). After identifying a group of colour diagnostic objects, an experiential rating scale was implored, with six phenomenological descriptors assigned a numerical value from 0 to 5 with the lowest descriptor assigned an experiential value of 0 and the highest descriptor – always, assigned an experiential value of 5. Objects with high experiential value (≥4) were referred to as frequently experienced colour diagnostic objects while objects with low experiential value (<4) were referred to as infrequent colour diagnostic objects. In the main study, which included four conditions – colour neutral, name neutral, name Stroop, colour Stroop - I measured how quickly observers were able to select the typical hue or typical hue category of achromatic frequently experienced and infrequent colour diagnostic objects, using an object Stroop decision-time task. The object representation of the objects phenomenologically categorized as frequently experienced colour diagnostic objects includes not only the prototypical colour typically associated with these objects but also the correct non-prototypical colour these objects are commonly experienced in. As for the representation of the objects phenomenologically categorized as infrequent colour diagnostic objects, the object representation of these objects only includes their prototypical colour. For this reason, I hypothesized that for the frequently experienced colour diagnostic objects, observers should take longer to recover their typical hue and typical hue category due to these objects’ contextual associations which ultimately facilitates the mental activation of these objects’ correct non prototypical colour. On the other hand, for infrequent colour diagnostic objects observers would be quicker in recovering the objects’ typical hue and typical hue category as the activation of these objects’ colour is non-contextual, which therefore leads to the activation of a single colour. In one out of the four conditions, results for the object Stroop decision-time task demonstrated that observers on average took longer to recover the typical hue but not the typical hue category for the frequently experienced colour diagnostic objects when compared to the infrequent colour diagnostic objects. In general, results from this study support the idea that the object representations of colour diagnostic objects not only include their prototypical colour on multiple domains (Naor-Raz and Tarr, 2003), but that their correct non-prototypical colours may also may be represented on the conceptual and lexical domain, additional information human observers are able to use as they quickly attempt to recognize these objects in atypical perceptual conditions.Adherence in behavioural interventions for stroke patients : measurement and predictionJoice, Sara A.https://hdl.handle.net/10023/72622019-07-01T10:11:56Z2005-01-01T00:00:00ZBackground: With the increasing incidence in stroke and the resultant high prevalence of residual disability resources are not adequately meeting the needs of the patients. Furthermore patients continue to express dissatisfaction with their care. New interventions are being developed and evaluated. However, when offered these new interventions, patients may refuse or not participate fully. A stroke workbook intervention was developed through a line of research examining the role of perceived control in recovery. During the randomised controlled trial (RCT) evaluating its efficacy patients failed to fully participate in the activities proposed in the workbook. Why, when there is such a dearth of treatment available, do stroke patients not fully participate in or adhere to the interventions offered?
Methods: Three studies were conducted, a predictive study using the intervention group of the RCT exploring the demographic, clinical and psychological factors predicting adherence; a predictive study using one of the intervention groups from a larger 2x2 RCT to examine the predictors of adherence to an easier intervention (video); and a third longitudinal study examining the efficacy of an even simpler intervention (letter) on increasing adherence to the video. The theoretical framework of Leventhal’s Self Regulation Model was used to develop the letter intervention and to explain the findings.
Results: Five types of adherence behaviours emerged from the three studies, all with their own difficulties of definition, measurement and their individual predictor variables. Gender, impairment and illness representations were all predictive of adherence. An easier intervention promoted adherence especially for men and the more impaired. Women appeared to adhere more readily to the complex intervention. These gender differences may be associated with illness representations. A theoretical-based letter does not increase adherence per se but may increase the amount of adherence to an easier intervention.
Conclusion: Adherence behaviour is not one type of behaviour and is associated with measurement difficulties. The Self-Regulation model appeared to offer some logical explanations to the findings. The findings have clinical implications and could possibly be associated with patients’ satisfaction with care.
2005-01-01T00:00:00ZJoice, Sara A.Background: With the increasing incidence in stroke and the resultant high prevalence of residual disability resources are not adequately meeting the needs of the patients. Furthermore patients continue to express dissatisfaction with their care. New interventions are being developed and evaluated. However, when offered these new interventions, patients may refuse or not participate fully. A stroke workbook intervention was developed through a line of research examining the role of perceived control in recovery. During the randomised controlled trial (RCT) evaluating its efficacy patients failed to fully participate in the activities proposed in the workbook. Why, when there is such a dearth of treatment available, do stroke patients not fully participate in or adhere to the interventions offered?
Methods: Three studies were conducted, a predictive study using the intervention group of the RCT exploring the demographic, clinical and psychological factors predicting adherence; a predictive study using one of the intervention groups from a larger 2x2 RCT to examine the predictors of adherence to an easier intervention (video); and a third longitudinal study examining the efficacy of an even simpler intervention (letter) on increasing adherence to the video. The theoretical framework of Leventhal’s Self Regulation Model was used to develop the letter intervention and to explain the findings.
Results: Five types of adherence behaviours emerged from the three studies, all with their own difficulties of definition, measurement and their individual predictor variables. Gender, impairment and illness representations were all predictive of adherence. An easier intervention promoted adherence especially for men and the more impaired. Women appeared to adhere more readily to the complex intervention. These gender differences may be associated with illness representations. A theoretical-based letter does not increase adherence per se but may increase the amount of adherence to an easier intervention.
Conclusion: Adherence behaviour is not one type of behaviour and is associated with measurement difficulties. The Self-Regulation model appeared to offer some logical explanations to the findings. The findings have clinical implications and could possibly be associated with patients’ satisfaction with care.Stimulation of glia reveals modulation of mammalian spinal motor networks by adenosineActon, DavidMiles, Gareth B.https://hdl.handle.net/10023/72342023-04-18T10:02:01Z2015-08-07T00:00:00ZDespite considerable evidence that glia can release modulators to influence the excitability of neighbouring neurons, the importance of gliotransmission for the operation of neural networks and in shaping behaviour remains controversial. Here we characterise the contribution of glia to the modulation of the mammalian spinal central pattern generator for locomotion, the output of which is directly relatable to a defined behaviour. Glia were stimulated by specific activation of protease-activated receptor-1 (PAR1), an endogenous G-protein coupled receptor preferentially expressed by spinal glia during ongoing activity of the spinal central pattern generator for locomotion. Selective activation of PAR1 by the agonist TFLLR resulted in a reversible reduction in the frequency of locomotor-related bursting recorded from ventral roots of spinal cord preparations isolated from neonatal mice. In the presence of the gliotoxins methionine sulfoximine or fluoroacetate, TFLLR had no effect, confirming the specificity of PAR1 activation to glia. The modulation of burst frequency upon PAR1 activation was blocked by the non-selective adenosine-receptor antagonist theophylline and by the A1-receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine, but not by the A2A-receptor antagonist SCH5826, indicating production of extracellular adenosine upon glial stimulation, followed by A1-receptor mediated inhibition of neuronal activity. Modulation of network output following glial stimulation was also blocked by the ectonucleotidase inhibitor ARL67156, indicating glial release of ATP and its subsequent degradation to adenosine rather than direct release of adenosine. Glial stimulation had no effect on rhythmic activity recorded following blockade of inhibitory transmission, suggesting that glial cell-derived adenosine acts via inhibitory circuit components to modulate locomotor-related output. Finally, the modulation of network output by endogenous adenosine was found to scale with the frequency of network activity, implying activity-dependent release of adenosine. Together, these data indicate that glia play an active role in the modulation of mammalian locomotor networks, providing negative feedback control that may stabilise network activity.
This work was funded by the Wellcome Trust Institutional Strategic Support Fund for University of St. Andrews.
2015-08-07T00:00:00ZActon, DavidMiles, Gareth B.Despite considerable evidence that glia can release modulators to influence the excitability of neighbouring neurons, the importance of gliotransmission for the operation of neural networks and in shaping behaviour remains controversial. Here we characterise the contribution of glia to the modulation of the mammalian spinal central pattern generator for locomotion, the output of which is directly relatable to a defined behaviour. Glia were stimulated by specific activation of protease-activated receptor-1 (PAR1), an endogenous G-protein coupled receptor preferentially expressed by spinal glia during ongoing activity of the spinal central pattern generator for locomotion. Selective activation of PAR1 by the agonist TFLLR resulted in a reversible reduction in the frequency of locomotor-related bursting recorded from ventral roots of spinal cord preparations isolated from neonatal mice. In the presence of the gliotoxins methionine sulfoximine or fluoroacetate, TFLLR had no effect, confirming the specificity of PAR1 activation to glia. The modulation of burst frequency upon PAR1 activation was blocked by the non-selective adenosine-receptor antagonist theophylline and by the A1-receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine, but not by the A2A-receptor antagonist SCH5826, indicating production of extracellular adenosine upon glial stimulation, followed by A1-receptor mediated inhibition of neuronal activity. Modulation of network output following glial stimulation was also blocked by the ectonucleotidase inhibitor ARL67156, indicating glial release of ATP and its subsequent degradation to adenosine rather than direct release of adenosine. Glial stimulation had no effect on rhythmic activity recorded following blockade of inhibitory transmission, suggesting that glial cell-derived adenosine acts via inhibitory circuit components to modulate locomotor-related output. Finally, the modulation of network output by endogenous adenosine was found to scale with the frequency of network activity, implying activity-dependent release of adenosine. Together, these data indicate that glia play an active role in the modulation of mammalian locomotor networks, providing negative feedback control that may stabilise network activity.Perceptions of older adults in an ageing world : content, structure, and consequences of age-related auto-stereotypesPersson, Joanne K.https://hdl.handle.net/10023/70562019-07-01T10:07:36Z2014-06-24T00:00:00ZThe current thesis explored participants’ stereotypes and auto-stereotypes of old age within the UK, and the consequences of auto-stereotype activation on older adults’ memory performance and well-being. Study 1 employed a questionnaire design to explore young (aged 17-25 years) and older adults’ (aged 60-75 years) experiences and stereotypes of ageing. Older participants demonstrated high subjective age bias, reporting subjective ages significantly below their chronological age. Older adults also demonstrated a greater understanding of positive aspects of old age than young adults, although no significant differences emerged between cohorts over the valence of generated stereotype content. Study 2 modified the questionnaire to further differentiate between more positive versus less negative aspects of ageing. Findings indicated that although older adults displayed less negative perceptions of old age than young adults, they did not demonstrate more positive representations. Study 3 explored the structure (as opposed to content) of age-related stereotypes using a free-sorting task, and included old-old adult participants (aged 75-91 years). Confirming previous findings, subtype structure formed two high level clusters, consisting of positive or negative categories. Old-old adults demonstrated the most complex subtype structure from the three groups, with no significant differences emerging between young and older adults. Finally, Study 4 employed a subliminal priming paradigm to examine the impact of positive or negative auto-stereotype activation on older adults’ memory performance and well-being. Findings suggested that negative auto-stereotype activation had a detrimental impact on participants’ memory performance, although the low power of the study means additional work is required to confirm this effect pattern. No significant effects of priming emerged for young adults. In summary, the current findings suggest that stereotypes and auto-stereotypes of old age are complex, consisting of both positive and negative elements, and point to the importance of considering subjective, rather than chronological age when assessing age-related identity.
2014-06-24T00:00:00ZPersson, Joanne K.The current thesis explored participants’ stereotypes and auto-stereotypes of old age within the UK, and the consequences of auto-stereotype activation on older adults’ memory performance and well-being. Study 1 employed a questionnaire design to explore young (aged 17-25 years) and older adults’ (aged 60-75 years) experiences and stereotypes of ageing. Older participants demonstrated high subjective age bias, reporting subjective ages significantly below their chronological age. Older adults also demonstrated a greater understanding of positive aspects of old age than young adults, although no significant differences emerged between cohorts over the valence of generated stereotype content. Study 2 modified the questionnaire to further differentiate between more positive versus less negative aspects of ageing. Findings indicated that although older adults displayed less negative perceptions of old age than young adults, they did not demonstrate more positive representations. Study 3 explored the structure (as opposed to content) of age-related stereotypes using a free-sorting task, and included old-old adult participants (aged 75-91 years). Confirming previous findings, subtype structure formed two high level clusters, consisting of positive or negative categories. Old-old adults demonstrated the most complex subtype structure from the three groups, with no significant differences emerging between young and older adults. Finally, Study 4 employed a subliminal priming paradigm to examine the impact of positive or negative auto-stereotype activation on older adults’ memory performance and well-being. Findings suggested that negative auto-stereotype activation had a detrimental impact on participants’ memory performance, although the low power of the study means additional work is required to confirm this effect pattern. No significant effects of priming emerged for young adults. In summary, the current findings suggest that stereotypes and auto-stereotypes of old age are complex, consisting of both positive and negative elements, and point to the importance of considering subjective, rather than chronological age when assessing age-related identity.The organisational effects of adolescent gonadal hormones on behavioural development in ratsKulbarsh, Kyle D.https://hdl.handle.net/10023/70552019-04-01T10:41:52Z2014-06-01T00:00:00ZGonadal steroid hormones play an important role in adolescent neural and behavioural development, causing changes that can be seen throughout life. Endogenous hormones have a direct impact on behaviour in both immediate and permanent ways by acting on multiple regions of the brain. The mechanisms that underlie the emergence of sexual and risk-taking behaviour during this time frame are yet to be fully understood. By using pharmacologic and surgical methods of suppressing gonadal steroids during adolescence, the effects of hormonal exposure on brain and behavioural development were examined in Lister-hooded rats (Rattus norvegicus). In these experiments, gonadal hormones were blocked in rats throughout adolescence using either gonadectomies or a pharmacological agent, then physical and behavioural measures were assessed into adulthood. Using a battery of behavioural tests including the elevated plus maze, light-dark box, open field test, and social tasks, the development of adult-typical anxiety-like, social, and risk-taking behaviours were evaluated. Males exposed to lower levels of testosterone during adolescence exhibited more feminized behaviour than their male counter-parts with unaltered levels of testosterone, including lower levels of anxiety-like behaviour in the elevated plus maze and light-dark box, as well as decreased social interactions in the juvenile play task and social preference test. These results provide evidence for the organisational effects of testosterone during adolescence on the development of behaviour, thus supporting the growing body of literature linking time-sensitive hormonal exposure to behavioural development.
2014-06-01T00:00:00ZKulbarsh, Kyle D.Gonadal steroid hormones play an important role in adolescent neural and behavioural development, causing changes that can be seen throughout life. Endogenous hormones have a direct impact on behaviour in both immediate and permanent ways by acting on multiple regions of the brain. The mechanisms that underlie the emergence of sexual and risk-taking behaviour during this time frame are yet to be fully understood. By using pharmacologic and surgical methods of suppressing gonadal steroids during adolescence, the effects of hormonal exposure on brain and behavioural development were examined in Lister-hooded rats (Rattus norvegicus). In these experiments, gonadal hormones were blocked in rats throughout adolescence using either gonadectomies or a pharmacological agent, then physical and behavioural measures were assessed into adulthood. Using a battery of behavioural tests including the elevated plus maze, light-dark box, open field test, and social tasks, the development of adult-typical anxiety-like, social, and risk-taking behaviours were evaluated. Males exposed to lower levels of testosterone during adolescence exhibited more feminized behaviour than their male counter-parts with unaltered levels of testosterone, including lower levels of anxiety-like behaviour in the elevated plus maze and light-dark box, as well as decreased social interactions in the juvenile play task and social preference test. These results provide evidence for the organisational effects of testosterone during adolescence on the development of behaviour, thus supporting the growing body of literature linking time-sensitive hormonal exposure to behavioural development.Retrieval processes in social identificationGriffiths, Alexander Ivorhttps://hdl.handle.net/10023/69562023-10-12T15:14:35Z2015-06-23T00:00:00ZThe utility of selective retrieval processes in our everyday lives is evident across the varied contexts we are subjected to as human beings. Memory is characterised by an unlimited storage capacity, but limited retrieval capacity. Subsequently, we are selective in what we remember in a given context in order to use memory in an adaptive manner. Previous theory places memory at the centre of deriving and maintaining a sense of self and personal identity. In contrast however, the extent to which memory serves the representation of social identities and the groups to which they are linked is unclear. As social identities are said to be the extension of the self to the social context, the present empirical investigation examined the role of selective processes of retrieval and forgetting on the remembrance of social identity and group-based information in the areas of gender, religious, partisan, and ideological identity.
Findings illustrated that we implicitly preserve and retrieve information that is relevant to our sense of social identity, whilst forgetting and implicitly diminishing information that is irrelevant. The findings also established that information retrieved not only pertains to the in-groups in which we seek membership, but also of opposing out-groups that seek to contrast and potentially challenge our in-group’s worldview. Furthermore, mechanisms and structures that support the representation of self were extended to the findings, delineating how processes of organisational and distinctive processing support the retrieval of social identity-based information of relevance and importance. The thesis concludes with the assertion that memory is not only the looking glass through which we see the reflection of the self, but also serves to act as the reflection through which we acquaint ourselves with, and relate ourselves to, our significant others in the social context.
2015-06-23T00:00:00ZGriffiths, Alexander IvorThe utility of selective retrieval processes in our everyday lives is evident across the varied contexts we are subjected to as human beings. Memory is characterised by an unlimited storage capacity, but limited retrieval capacity. Subsequently, we are selective in what we remember in a given context in order to use memory in an adaptive manner. Previous theory places memory at the centre of deriving and maintaining a sense of self and personal identity. In contrast however, the extent to which memory serves the representation of social identities and the groups to which they are linked is unclear. As social identities are said to be the extension of the self to the social context, the present empirical investigation examined the role of selective processes of retrieval and forgetting on the remembrance of social identity and group-based information in the areas of gender, religious, partisan, and ideological identity.
Findings illustrated that we implicitly preserve and retrieve information that is relevant to our sense of social identity, whilst forgetting and implicitly diminishing information that is irrelevant. The findings also established that information retrieved not only pertains to the in-groups in which we seek membership, but also of opposing out-groups that seek to contrast and potentially challenge our in-group’s worldview. Furthermore, mechanisms and structures that support the representation of self were extended to the findings, delineating how processes of organisational and distinctive processing support the retrieval of social identity-based information of relevance and importance. The thesis concludes with the assertion that memory is not only the looking glass through which we see the reflection of the self, but also serves to act as the reflection through which we acquaint ourselves with, and relate ourselves to, our significant others in the social context.Memory inhibition across the lifespanTeale, Julia C.https://hdl.handle.net/10023/69102019-07-01T10:14:32Z2015-06-23T00:00:00ZAge can affect memory performance. This statement is so often heard that it has become almost a truism. When research surrounding memory inhibition – the ability to ignore irrelevant material to aid in the retrieval of a target memory – is examined specifically, a more mixed picture of findings emerges. Whilst some previous work has found evidence of an age-related deficit, other research has rather found intact memory inhibition in older adults. Less often discussed, too, are the effects of individual differences on memory inhibition in addition to age, including differences in metacognitive strategy, working memory capacity, stress and mood. The present thesis set out primarily to investigate the effects of age on memory inhibition chiefly using cognitive experimental paradigms, and also to investigate potential individual differences in this ability which exist across the lifespan. The findings of the present thesis showed that age alone was not related to a deficit in memory inhibition, - young and older adults rather showed equivalent levels of inhibitory forgetting on two different paradigms, when methodological measures were put in place to control for alternative, interference-based explanations (Study 1). These findings also could not be explained by differences in metacognitive, covert-cuing strategies (Study 2). Instead, age-related inhibitory deficits were qualified by differences in working memory capacity (Study 3a & b). In combination, older age and low working memory capacity were related to impaired memory inhibition, whereas young age or high working memory capacity were not. Finally, natural variations in stress and mood over time were found to be related to significant differences in working memory capacity, but not memory inhibition (Study 4). This suggests that these important cognitive abilities may be capable of changing even over relatively short time periods, and thus they may also potentially be improved, - a proposal which is considered in the General Discussion.
2015-06-23T00:00:00ZTeale, Julia C.Age can affect memory performance. This statement is so often heard that it has become almost a truism. When research surrounding memory inhibition – the ability to ignore irrelevant material to aid in the retrieval of a target memory – is examined specifically, a more mixed picture of findings emerges. Whilst some previous work has found evidence of an age-related deficit, other research has rather found intact memory inhibition in older adults. Less often discussed, too, are the effects of individual differences on memory inhibition in addition to age, including differences in metacognitive strategy, working memory capacity, stress and mood. The present thesis set out primarily to investigate the effects of age on memory inhibition chiefly using cognitive experimental paradigms, and also to investigate potential individual differences in this ability which exist across the lifespan. The findings of the present thesis showed that age alone was not related to a deficit in memory inhibition, - young and older adults rather showed equivalent levels of inhibitory forgetting on two different paradigms, when methodological measures were put in place to control for alternative, interference-based explanations (Study 1). These findings also could not be explained by differences in metacognitive, covert-cuing strategies (Study 2). Instead, age-related inhibitory deficits were qualified by differences in working memory capacity (Study 3a & b). In combination, older age and low working memory capacity were related to impaired memory inhibition, whereas young age or high working memory capacity were not. Finally, natural variations in stress and mood over time were found to be related to significant differences in working memory capacity, but not memory inhibition (Study 4). This suggests that these important cognitive abilities may be capable of changing even over relatively short time periods, and thus they may also potentially be improved, - a proposal which is considered in the General Discussion.We are what we remember : an examination of autobiographical memory across the lifespan and the impact of Alzheimer’s diseaseLonson, Celeste Shin-Ruhttps://hdl.handle.net/10023/66112019-04-01T10:40:35Z2014-10-01T00:00:00Z“If you could somehow reprogram a person’s brain and change a significant memory in someone’s life, would that individual become someone else entirely?” According to McAdams (1985), a loss of autobiographical memory (AM) can be seen as a loss of identity, as identity is based on our personal experiences. As it is not currently possible to target and then alter specific memories within an individual brain, the AM of a healthy older group were compared to a group with Alzheimer’s disease (AD). The main question of this thesis was, “does a loss in AM result in a loss of identity?” This thesis explores AM across the life course through a series of four experiments with young and older adults, including a group with AD. Results support the critical role of the working-self in determining the self-relevance of AM across the lifespan.
2014-10-01T00:00:00ZLonson, Celeste Shin-Ru“If you could somehow reprogram a person’s brain and change a significant memory in someone’s life, would that individual become someone else entirely?” According to McAdams (1985), a loss of autobiographical memory (AM) can be seen as a loss of identity, as identity is based on our personal experiences. As it is not currently possible to target and then alter specific memories within an individual brain, the AM of a healthy older group were compared to a group with Alzheimer’s disease (AD). The main question of this thesis was, “does a loss in AM result in a loss of identity?” This thesis explores AM across the life course through a series of four experiments with young and older adults, including a group with AD. Results support the critical role of the working-self in determining the self-relevance of AM across the lifespan.Social complexity in a large and small group of olive baboonsSambrook, Thomas Danielhttps://hdl.handle.net/10023/64982019-07-01T10:16:41Z1996-01-01T00:00:00ZGroup size is known to correlate with various indices of brain size in the primates. The possibility that increases in group size foster social complexity forms the central empirical topic of this thesis. A ten month field study of olive baboons, Papio cynocephalus anubis, was carried out on the Laikipia Plateau, Kenya. Data were collected on a wide range of social behaviours in two troops, one smaller than the mean group size for Papio and one larger.
The concepts of complexity and social complexity are critically examined with a view to their quantification in behaviour and cognition. The status of social complexity in the debate concerning the evolution of high intelligence in the Primate Order is discussed. Dimensions of social complexity are developed and then investigated empirically.
Females in the two troops showed similar grooming frequencies and grooming network sizes. However, the troops differed in the patterning of their grooming with respect to rank: individuals in the small troop groomed those of high rank, individuals in the large troop groomed those of rank similar to themselves.
Cluster analysis of spatial proximities showed no sign of cliquishness in either troop.
Females formed associations with particular males ('friendships') in both troops but there were no clear differences in either the number or stability of these associations.
The rate of interaction was higher in the large troop, but, proportional to total interaction rates, the rates of agonistic and polyadic interactions were not. The rate of interaction was higher for adult and sub-adult females than for adult and sub-adult males. In comparison, the proportion of interactions that were agonistic was greater for the adult and sub-adult males.
The variability of response to affiliation that individuals faced was the same across the two troops. Males, however, faced more variability than did females largely because of a high number of avoidant responses.
The absence of strong differences in social complexity between differently sized troops suggests that, proximally, cognitive complexity limits social complexity. Thus, interspecific comparisons may prove to be the most fertile area of research into complexity in the future.
1996-01-01T00:00:00ZSambrook, Thomas DanielGroup size is known to correlate with various indices of brain size in the primates. The possibility that increases in group size foster social complexity forms the central empirical topic of this thesis. A ten month field study of olive baboons, Papio cynocephalus anubis, was carried out on the Laikipia Plateau, Kenya. Data were collected on a wide range of social behaviours in two troops, one smaller than the mean group size for Papio and one larger.
The concepts of complexity and social complexity are critically examined with a view to their quantification in behaviour and cognition. The status of social complexity in the debate concerning the evolution of high intelligence in the Primate Order is discussed. Dimensions of social complexity are developed and then investigated empirically.
Females in the two troops showed similar grooming frequencies and grooming network sizes. However, the troops differed in the patterning of their grooming with respect to rank: individuals in the small troop groomed those of high rank, individuals in the large troop groomed those of rank similar to themselves.
Cluster analysis of spatial proximities showed no sign of cliquishness in either troop.
Females formed associations with particular males ('friendships') in both troops but there were no clear differences in either the number or stability of these associations.
The rate of interaction was higher in the large troop, but, proportional to total interaction rates, the rates of agonistic and polyadic interactions were not. The rate of interaction was higher for adult and sub-adult females than for adult and sub-adult males. In comparison, the proportion of interactions that were agonistic was greater for the adult and sub-adult males.
The variability of response to affiliation that individuals faced was the same across the two troops. Males, however, faced more variability than did females largely because of a high number of avoidant responses.
The absence of strong differences in social complexity between differently sized troops suggests that, proximally, cognitive complexity limits social complexity. Thus, interspecific comparisons may prove to be the most fertile area of research into complexity in the future.Psychophysical studies of interactions between luminance and chromatic information in human visionClery, Stéphanehttps://hdl.handle.net/10023/63762019-09-10T02:04:36Z2014-06-24T00:00:00ZIn this thesis, I investigated how human vision processes colour and
luminance information to enable perception of our environment. I first
tested how colour can alter the perception of depth from shading. A
luminance variation can be interpreted as either variation of
reflectance (patterning) or variation of shape. The process of
shape-from-shading interprets luminance variation as changes in the
shape of the object (e.g. the shading on an object might elicit the
perception of curvature). The addition of colour variation is known to
modify this shape-from-shading processing. In the experiments presented
here I tested how luminance driven percepts can be modified by colour.
My first series of experiments confirmed that depth is modulated by
colour. I explored a larger number of participants than previously
tested. Contrary to previous studies, a wide repertoire of behaviour was
found; participants experienced variously more depth, or less depth, or
no difference. I hypothesised that the colour modulation effect might
be due to a low-level contrast modulation of luminance by colour, rather
than a higher-level depth effect. In a second series of experiments, I
therefore tested how the perceived contrast of a luminance target can be
affected by the presence of an orthogonal mask. I found that colour had
a range of effects on the perception of luminance, again dependant on
the participants. Luminance also had a similar wide range of effects on
the perceived contrast of luminance targets. This showed that, at
supra-threshold levels, a luminance target’s contrast can be modulated
by a component of another orientation (colour or luminance defined). The
effects of luminance and colour were not following a particular rule. In
a third series of experiments, I explored this interaction at detection
levels of contrast. I showed cross-interaction between luminance target
and mask but no effects of a colour mask.
Electronic version excludes material for which permission has not been granted by the rights holder
2014-06-24T00:00:00ZClery, StéphaneIn this thesis, I investigated how human vision processes colour and
luminance information to enable perception of our environment. I first
tested how colour can alter the perception of depth from shading. A
luminance variation can be interpreted as either variation of
reflectance (patterning) or variation of shape. The process of
shape-from-shading interprets luminance variation as changes in the
shape of the object (e.g. the shading on an object might elicit the
perception of curvature). The addition of colour variation is known to
modify this shape-from-shading processing. In the experiments presented
here I tested how luminance driven percepts can be modified by colour.
My first series of experiments confirmed that depth is modulated by
colour. I explored a larger number of participants than previously
tested. Contrary to previous studies, a wide repertoire of behaviour was
found; participants experienced variously more depth, or less depth, or
no difference. I hypothesised that the colour modulation effect might
be due to a low-level contrast modulation of luminance by colour, rather
than a higher-level depth effect. In a second series of experiments, I
therefore tested how the perceived contrast of a luminance target can be
affected by the presence of an orthogonal mask. I found that colour had
a range of effects on the perception of luminance, again dependant on
the participants. Luminance also had a similar wide range of effects on
the perceived contrast of luminance targets. This showed that, at
supra-threshold levels, a luminance target’s contrast can be modulated
by a component of another orientation (colour or luminance defined). The
effects of luminance and colour were not following a particular rule. In
a third series of experiments, I explored this interaction at detection
levels of contrast. I showed cross-interaction between luminance target
and mask but no effects of a colour mask.Humiliation : understanding its nature, experience and consequencesJogdand, Yashpal Ashokraohttps://hdl.handle.net/10023/63062023-03-20T14:41:05Z2015-01-01T00:00:00ZThis thesis examined the nature, experience and consequences of humiliation among Dalits (ex-Untouchables) in India (and also among UK students for comparative purposes). Social psychological research looks at humiliation as automatic, extreme and intense emotion which often leads to extreme and irrational behaviors (Lindner, 2002; Otten & Jonas, 2014; Elison & Harter, 2007). The research in this thesis contested this view and underlined the need to look at humiliation as 1) inherently relational or dynamic in nature, 2) a distinguishably group level phenomenon and 3) a mobilised phenomenon.
Study 1 analysed the experiences of humiliation among Dalits and conceptualised humiliation as a complex social encounter in which one party attempts to diminish identity of another party. Study 1 also identified important dimensions of humiliating encounters that were examined in subsequent studies.
Studies 2 - 3 manipulated perspective (victim or witness) and target of devaluation (personal identity or social identity) in a humiliating encounter and showed that the nature of humiliation and how it is experienced depends upon the way in which identities are defined in a humiliating encounter. Both UK students (Study 2) and Dalit participants (Study 3) confirmed the collective experience of humiliation i.e. one can feel humiliated simply by witnessing humiliation of another group member.
Studies 4 - 7 manipulated victim’s response (resistance vs. compliance) during a humiliating encounter. These studies showed that humiliation is an encounter within power relations and victims of humiliation possess choice and agency to change the outcome of humiliating encounters.
Study 8 analysed the humiliation rhetoric in the speeches of Dr. B. R. Ambedkar, the most important of Dalits leaders, and showed that the way in which humiliating encounter is resolved depends upon the mobilisation processes which can even change the nature of identities and, therefore, the nature of experience of the encounter.
2015-01-01T00:00:00ZJogdand, Yashpal AshokraoThis thesis examined the nature, experience and consequences of humiliation among Dalits (ex-Untouchables) in India (and also among UK students for comparative purposes). Social psychological research looks at humiliation as automatic, extreme and intense emotion which often leads to extreme and irrational behaviors (Lindner, 2002; Otten & Jonas, 2014; Elison & Harter, 2007). The research in this thesis contested this view and underlined the need to look at humiliation as 1) inherently relational or dynamic in nature, 2) a distinguishably group level phenomenon and 3) a mobilised phenomenon.
Study 1 analysed the experiences of humiliation among Dalits and conceptualised humiliation as a complex social encounter in which one party attempts to diminish identity of another party. Study 1 also identified important dimensions of humiliating encounters that were examined in subsequent studies.
Studies 2 - 3 manipulated perspective (victim or witness) and target of devaluation (personal identity or social identity) in a humiliating encounter and showed that the nature of humiliation and how it is experienced depends upon the way in which identities are defined in a humiliating encounter. Both UK students (Study 2) and Dalit participants (Study 3) confirmed the collective experience of humiliation i.e. one can feel humiliated simply by witnessing humiliation of another group member.
Studies 4 - 7 manipulated victim’s response (resistance vs. compliance) during a humiliating encounter. These studies showed that humiliation is an encounter within power relations and victims of humiliation possess choice and agency to change the outcome of humiliating encounters.
Study 8 analysed the humiliation rhetoric in the speeches of Dr. B. R. Ambedkar, the most important of Dalits leaders, and showed that the way in which humiliating encounter is resolved depends upon the mobilisation processes which can even change the nature of identities and, therefore, the nature of experience of the encounter.The goal trumps the means : highlighting goals is more beneficial than highlighting means in means-end trainingGerson, SarahWoodward, Amandahttps://hdl.handle.net/10023/61832023-04-18T09:57:48Z2013-04-01T00:00:00ZMeans-end actions are an early-emerging form of problem solving. These actions require initiating initial behaviors with a goal in mind. In this study, we explored the origins of 8-month-old infants’ means-end action production using a cloth-pulling training paradigm. We examined whether highlighting the goal (toy) or the means (cloth) was more valuable for learning to perform a well-organized means-end action. Infants were given the opportunity to both practice cloth-pulling and view modeling of the action performed by an adult throughout the session. Infants saw either the same toy or the same cloth in successive trials, so that the goal or means were highlighted prior to modeling of the action. All infants improved throughout the session regardless of which aspect of the event was highlighted. Beyond this general improvement, repetition of goals supported more rapid learning and more sustained learning than did repetition of means. These findings provide novel evidence that, at the origins of means-end action production, emphasizing the goal that structures an action facilitates the learning of new means-end actions.
This work was partially supported by a grant to the second author from NICHD (HD35707).
2013-04-01T00:00:00ZGerson, SarahWoodward, AmandaMeans-end actions are an early-emerging form of problem solving. These actions require initiating initial behaviors with a goal in mind. In this study, we explored the origins of 8-month-old infants’ means-end action production using a cloth-pulling training paradigm. We examined whether highlighting the goal (toy) or the means (cloth) was more valuable for learning to perform a well-organized means-end action. Infants were given the opportunity to both practice cloth-pulling and view modeling of the action performed by an adult throughout the session. Infants saw either the same toy or the same cloth in successive trials, so that the goal or means were highlighted prior to modeling of the action. All infants improved throughout the session regardless of which aspect of the event was highlighted. Beyond this general improvement, repetition of goals supported more rapid learning and more sustained learning than did repetition of means. These findings provide novel evidence that, at the origins of means-end action production, emphasizing the goal that structures an action facilitates the learning of new means-end actions.The contribution of the subthalamic nucleus to executive functions in ratXia, Shuanghttps://hdl.handle.net/10023/55452019-04-01T10:40:51Z2014-12-01T00:00:00ZLesions of the subthalamic nucleus (STN) alleviate the cardinal signs of
idiopathic as well as MPTP-induced Parkinson’s disease in primates. For this
reason, the STN is a target for clinical treatment of Parkinson’s disease using
deep brain stimulation. Despite its small size, the STN plays a vital role in the
cortico-basal ganglia-thalamic network. However, the functional features of the
STN have yet to be fully uncovered. The research presented in this thesis
examines the functions of the STN by measuring behavioural changes resulting
from STN lesions in rats performing executive abilities.
In the first experiment, a ‘signal change’ reaction time task was developed
and the performance of humans and rats was compared. The main findings
were that although humans and rats used different strategies in the task, the
task did challenge the ability to inhibit unwanted responses. In the second and
third experiments, the effects of bilateral lesions of the STN on performance of
two variants of the ‘signal change’ task were examined. Rats with the STN
lesions were able to inhibit responses when under stimulus control, but were
less able to inhibit responses that were not under stimulus control. In the final
experiment, the effects of lesions of the STN on inhibitory control in a nonmotor,
cognitive domain were examined. Rats with STN lesions were not
impaired on reversal learning, suggesting intact inhibition of previously
rewarded responses. The rats with STN lesions did show impairments in
selective attention which resulted in an inability to form an attentional set.
Together, these findings challenge the conventional view that the STN
simply plays a global inhibitory role. Rather, the contribution of the STN to
inhibitory control is more complex and neither the motor nor the cognitive
effects of the lesions are easily explained simply as a failure of inhibition.
2014-12-01T00:00:00ZXia, ShuangLesions of the subthalamic nucleus (STN) alleviate the cardinal signs of
idiopathic as well as MPTP-induced Parkinson’s disease in primates. For this
reason, the STN is a target for clinical treatment of Parkinson’s disease using
deep brain stimulation. Despite its small size, the STN plays a vital role in the
cortico-basal ganglia-thalamic network. However, the functional features of the
STN have yet to be fully uncovered. The research presented in this thesis
examines the functions of the STN by measuring behavioural changes resulting
from STN lesions in rats performing executive abilities.
In the first experiment, a ‘signal change’ reaction time task was developed
and the performance of humans and rats was compared. The main findings
were that although humans and rats used different strategies in the task, the
task did challenge the ability to inhibit unwanted responses. In the second and
third experiments, the effects of bilateral lesions of the STN on performance of
two variants of the ‘signal change’ task were examined. Rats with the STN
lesions were able to inhibit responses when under stimulus control, but were
less able to inhibit responses that were not under stimulus control. In the final
experiment, the effects of lesions of the STN on inhibitory control in a nonmotor,
cognitive domain were examined. Rats with STN lesions were not
impaired on reversal learning, suggesting intact inhibition of previously
rewarded responses. The rats with STN lesions did show impairments in
selective attention which resulted in an inability to form an attentional set.
Together, these findings challenge the conventional view that the STN
simply plays a global inhibitory role. Rather, the contribution of the STN to
inhibitory control is more complex and neither the motor nor the cognitive
effects of the lesions are easily explained simply as a failure of inhibition.A genetic algorithm for face fittingHunter, David WilliamTiddeman, Bernard PaulPerrett, David Ianhttps://hdl.handle.net/10023/54432022-04-14T20:39:20Z2012-02-01T00:00:00ZAccurate estimation of the shape of human faces has many applications from computer-imaging to psychological research. One well known method is to fit a Three Dimensional Morphable Model to a target image. This method is attractive as the faces it constructs are already projected onto an orthogonal basis making further manipulation and analysis easier. So far its use in these fields has been limited the inaccuracy and inconvenience of current face-fitting methods. We present a method based on Genetic Algorithms that avoid the local minima and gradient image errors that current methods suffer from. It has the added advantage of requiring no manual interaction to initialise or guide the fitting process.
2012-02-01T00:00:00ZHunter, David WilliamTiddeman, Bernard PaulPerrett, David IanAccurate estimation of the shape of human faces has many applications from computer-imaging to psychological research. One well known method is to fit a Three Dimensional Morphable Model to a target image. This method is attractive as the faces it constructs are already projected onto an orthogonal basis making further manipulation and analysis easier. So far its use in these fields has been limited the inaccuracy and inconvenience of current face-fitting methods. We present a method based on Genetic Algorithms that avoid the local minima and gradient image errors that current methods suffer from. It has the added advantage of requiring no manual interaction to initialise or guide the fitting process.Perceptual integration across natural monocular regionsZeiner, Katharina MariaSpitschan, ManuelHarris, Juliehttps://hdl.handle.net/10023/53492022-04-12T11:30:28Z2014-03-05T00:00:00ZNatural scenes contain hidden regions, or occlusions, that differ in the two eyes, resulting in monocular regions that can only be seen by one eye. Such monocular regions appear to not be suppressed but seem to be integrated into the scene percept. Here we explore how the two eyes' views are combined to represent a scene that contains monocular regions, partially hidden behind a foreground occluding “fence.” We measured performance in a density/numerosity discrimination task for scenes containing differing amounts of binocular and monocular information. We find that information from a number of separate monocular regions can be integrated into our overall percept of dot density/numerosity, although different observers use different strategies. If, however, both monocular and binocular information is present, observers appear to ignore the purely monocular regions, relying solely on the binocular information when making density/numerosity judgments. Our work suggests that binocular regions are favored over monocular regions, such that information from monocular regions is effectively ignored when binocular regions are present in a scene.
2014-03-05T00:00:00ZZeiner, Katharina MariaSpitschan, ManuelHarris, JulieNatural scenes contain hidden regions, or occlusions, that differ in the two eyes, resulting in monocular regions that can only be seen by one eye. Such monocular regions appear to not be suppressed but seem to be integrated into the scene percept. Here we explore how the two eyes' views are combined to represent a scene that contains monocular regions, partially hidden behind a foreground occluding “fence.” We measured performance in a density/numerosity discrimination task for scenes containing differing amounts of binocular and monocular information. We find that information from a number of separate monocular regions can be integrated into our overall percept of dot density/numerosity, although different observers use different strategies. If, however, both monocular and binocular information is present, observers appear to ignore the purely monocular regions, relying solely on the binocular information when making density/numerosity judgments. Our work suggests that binocular regions are favored over monocular regions, such that information from monocular regions is effectively ignored when binocular regions are present in a scene.Characterizing Visual Attention during Driving and Non-driving Hazard Perception TasksMacKenzie, Andrew KerrHarris, Juliehttps://hdl.handle.net/10023/50662023-04-19T00:38:43Z2014-03-26T00:00:00ZResearch into driving skill, particularly of hazard perception, often involves studies where participants either view pictures of driving scenarios or use movie viewing paradigms. However oculomotor strategies tend to change between active and passive tasks and attentional limitations are introduced during real driving. Here we present a study using eye tracking methods, to contrast oculomotor behaviour differences across a passive video based hazard perception task and an active hazard perception simulated driving task. The differences presented highlight a requirement to study driving skill under more active conditions, where the participant is engaged with a driving task. Our results suggest that more standard, passive tests, may have limited utility when developing visual models of driving behaviour. The results presented here have implications for driver safety measures and provide further insights into how vision and action interact during natural activity.
Funding: EPSRC DTG
2014-03-26T00:00:00ZMacKenzie, Andrew KerrHarris, JulieResearch into driving skill, particularly of hazard perception, often involves studies where participants either view pictures of driving scenarios or use movie viewing paradigms. However oculomotor strategies tend to change between active and passive tasks and attentional limitations are introduced during real driving. Here we present a study using eye tracking methods, to contrast oculomotor behaviour differences across a passive video based hazard perception task and an active hazard perception simulated driving task. The differences presented highlight a requirement to study driving skill under more active conditions, where the participant is engaged with a driving task. Our results suggest that more standard, passive tests, may have limited utility when developing visual models of driving behaviour. The results presented here have implications for driver safety measures and provide further insights into how vision and action interact during natural activity.Behavioral observation of xenopus tadpole swimming for neuroscience labsLi, WenchangWagner, Monica AnnePorter, Nicola Jeanhttps://hdl.handle.net/10023/50382023-04-18T09:51:38Z2014-01-01T00:00:00ZNeuroscience labs benefit from reliable, easily - monitored neural responses mediated by well - studied neural pathways . Xenopus laevis tadpoles have been used as a simple vertebrate model preparation in motor control studies. Most of the neuronal pathways underlying different aspects of tadpole swimming behavior have been revealed. These include the skin mechanosensory touch and pineal eye light - sensing pathways whose activation can initiate swimming , and the cement gland pressure - sensing pathway responsible for stopping swimming. A simple transection in the hindbrain can cut off the pineal eye and cement gland pathways from the swimming circuit in the spinal cord, resulting in losses of corresponding functions. Additionally, some pharmacological experiments targeting neurotransmission can be designed to affect swimming and, fluorescence - conjugated α -bungarotoxin can be used to label nicotinic receptors at neuromuscular junctions. These experiments can be readily adapted for undergraduate neuroscience teaching labs. Possible expansions of some experiments for more sophisticated pharmacological or neurophysiological labs are also discussed.
2014-01-01T00:00:00ZLi, WenchangWagner, Monica AnnePorter, Nicola JeanNeuroscience labs benefit from reliable, easily - monitored neural responses mediated by well - studied neural pathways . Xenopus laevis tadpoles have been used as a simple vertebrate model preparation in motor control studies. Most of the neuronal pathways underlying different aspects of tadpole swimming behavior have been revealed. These include the skin mechanosensory touch and pineal eye light - sensing pathways whose activation can initiate swimming , and the cement gland pressure - sensing pathway responsible for stopping swimming. A simple transection in the hindbrain can cut off the pineal eye and cement gland pathways from the swimming circuit in the spinal cord, resulting in losses of corresponding functions. Additionally, some pharmacological experiments targeting neurotransmission can be designed to affect swimming and, fluorescence - conjugated α -bungarotoxin can be used to label nicotinic receptors at neuromuscular junctions. These experiments can be readily adapted for undergraduate neuroscience teaching labs. Possible expansions of some experiments for more sophisticated pharmacological or neurophysiological labs are also discussed.Modelling the effects of deep brain stimulation in the pedunculopontine tegmental nucleus in Parkinson’s diseaseGut, Nadine Katrinhttps://hdl.handle.net/10023/48932019-04-01T10:41:46Z2014-06-24T00:00:00ZBased on the belief that it is a locomotor control structure, the pedunculopontine tegmental nucleus (PPTg) has been considered a potential target for deep brain stimulation (DBS) for Parkinson’s disease (PD) patients with symptoms refractory to medication and/or stimulation of established target sites. To date, a number of patients have been implanted with PPTg electrodes with mostly disappointing results. Exact target site in PPTg, possible mechanisms of PPTg-DBS and likely potential benefits need to be systematically explored before consideration of further clinical application.
The research described here approaches these questions by (i) investigating the role of the PPTg in gait per se; (ii) developing a refined model of PD that mimics the underlying pathophysiology by including partial loss of the PPTg itself; (iii) adapting a wireless device to let rats move freely while receiving DBS; and (iv) investigating the effect of DBS at different sites in the PPTg on gait and posture in the traditional and refined model of PD.
Underlining the concern that understanding the PPTg as a locomotor control structure is inadequate, the experiments showed that neither partial nor complete lesions of PPTg caused gait deficits. The refined model showed hardly any differences compared to the standard one, but the effect of DBS in each was very different, highlighting the need to take degeneration in the PPTg into consideration when investigating it as a DBS target. The differential results of anterior and posterior PPTg-DBS show the critical importance of intra-PPTg DBS location: Anterior PPTg electrodes caused severe freezing and worsened gait while some gait parameters improved with stimulation of posterior PPTg.
The results suggest mechanisms of PPTg-DBS beyond the proposed activation of over-inhibited PPTg neurons, including aggravation of already dysfunctional inhibitory input by anterior PPTg-DBS and activation of ascending projections from posterior PPTg to the forebrain.
2014-06-24T00:00:00ZGut, Nadine KatrinBased on the belief that it is a locomotor control structure, the pedunculopontine tegmental nucleus (PPTg) has been considered a potential target for deep brain stimulation (DBS) for Parkinson’s disease (PD) patients with symptoms refractory to medication and/or stimulation of established target sites. To date, a number of patients have been implanted with PPTg electrodes with mostly disappointing results. Exact target site in PPTg, possible mechanisms of PPTg-DBS and likely potential benefits need to be systematically explored before consideration of further clinical application.
The research described here approaches these questions by (i) investigating the role of the PPTg in gait per se; (ii) developing a refined model of PD that mimics the underlying pathophysiology by including partial loss of the PPTg itself; (iii) adapting a wireless device to let rats move freely while receiving DBS; and (iv) investigating the effect of DBS at different sites in the PPTg on gait and posture in the traditional and refined model of PD.
Underlining the concern that understanding the PPTg as a locomotor control structure is inadequate, the experiments showed that neither partial nor complete lesions of PPTg caused gait deficits. The refined model showed hardly any differences compared to the standard one, but the effect of DBS in each was very different, highlighting the need to take degeneration in the PPTg into consideration when investigating it as a DBS target. The differential results of anterior and posterior PPTg-DBS show the critical importance of intra-PPTg DBS location: Anterior PPTg electrodes caused severe freezing and worsened gait while some gait parameters improved with stimulation of posterior PPTg.
The results suggest mechanisms of PPTg-DBS beyond the proposed activation of over-inhibited PPTg neurons, including aggravation of already dysfunctional inhibitory input by anterior PPTg-DBS and activation of ascending projections from posterior PPTg to the forebrain.Evaluating multicenter DTI data in Huntington's disease on site specific effects : an ex post facto approachMüller, Hans-PeterGrön, GeorgSprengelmeyer, ReinerKassubek, JanLudolph, Albert C.Hobbs, NicolaCole, JamesRoos, Raymund A.C.Duerr, AlexandraTabrizi, Sarah J.Landwehrmeyer, G. BernhardSüssmuth, Sigurd D.https://hdl.handle.net/10023/47892023-04-18T09:48:23Z2013-01-01T00:00:00ZPurpose: Assessment of the feasibility to average diffusion tensor imaging (DTI) metrics of MRI data acquired in the course of a multicenter study. Materials and methods: Sixty-one early stage Huntington's disease patients and forty healthy controls were studied using four different MR scanners at four European sites with acquisition protocols as close as possible to a given standard protocol. The potential and feasibility of averaging data acquired at different sites was evaluated quantitatively by region-of-interest (ROI) based statistical comparisons of coefficients of variation (CV) across centers, as well as by testing for significant group-by-center differences on averaged fractional anisotropy (FA) values between patients and controls. In addition, a whole-brain based statistical between-group comparison was performed using FA maps. Results: The ex post facto statistical evaluation of CV and FA-values in a priori defined ROIs showed no differences between sites above chance indicating that data were not systematically biased by center specific factors. Conclusion: Averaging FA-maps from DTI data acquired at different study sites and different MR scanner types does not appear to be systematically biased. A suitable recipe for testing on the possibility to pool multicenter DTI data is provided to permit averaging of DTI-derived metrics to differentiate patients from healthy controls at a larger scale.
2013-01-01T00:00:00ZMüller, Hans-PeterGrön, GeorgSprengelmeyer, ReinerKassubek, JanLudolph, Albert C.Hobbs, NicolaCole, JamesRoos, Raymund A.C.Duerr, AlexandraTabrizi, Sarah J.Landwehrmeyer, G. BernhardSüssmuth, Sigurd D.Purpose: Assessment of the feasibility to average diffusion tensor imaging (DTI) metrics of MRI data acquired in the course of a multicenter study. Materials and methods: Sixty-one early stage Huntington's disease patients and forty healthy controls were studied using four different MR scanners at four European sites with acquisition protocols as close as possible to a given standard protocol. The potential and feasibility of averaging data acquired at different sites was evaluated quantitatively by region-of-interest (ROI) based statistical comparisons of coefficients of variation (CV) across centers, as well as by testing for significant group-by-center differences on averaged fractional anisotropy (FA) values between patients and controls. In addition, a whole-brain based statistical between-group comparison was performed using FA maps. Results: The ex post facto statistical evaluation of CV and FA-values in a priori defined ROIs showed no differences between sites above chance indicating that data were not systematically biased by center specific factors. Conclusion: Averaging FA-maps from DTI data acquired at different study sites and different MR scanner types does not appear to be systematically biased. A suitable recipe for testing on the possibility to pool multicenter DTI data is provided to permit averaging of DTI-derived metrics to differentiate patients from healthy controls at a larger scale.Regarding societal changeBlackwood, Leda MooreLivingstone, AndrewLeach, Colinhttps://hdl.handle.net/10023/45722023-04-18T09:51:18Z2013-12-01T00:00:00ZIn this paper we introduce our special thematic section on societal change.We begin by providing an overview of the aims of the section, and how these aims grew out of a need to address conceptual and empirical challenges in the study of societal change. In response to these challenges, the section was intended to provide a forum for theoretical and empirical work from a range of disciplinary perspectives on how societies change, and how such change can be understood. Together, the contributions argue for (1) the need to contextualize the study of societal change, (2) the value of considering factors and processes other than collective action in transforming societies, (3) the importance of ideology and its operation through social institutions such as news media, and (4) an imperative to ensure that our research is fully engaged with society in terms of its grounding in social issues, its sensitivity to our own social context as researchers, and in its practices and outcomes.
2013-12-01T00:00:00ZBlackwood, Leda MooreLivingstone, AndrewLeach, ColinIn this paper we introduce our special thematic section on societal change.We begin by providing an overview of the aims of the section, and how these aims grew out of a need to address conceptual and empirical challenges in the study of societal change. In response to these challenges, the section was intended to provide a forum for theoretical and empirical work from a range of disciplinary perspectives on how societies change, and how such change can be understood. Together, the contributions argue for (1) the need to contextualize the study of societal change, (2) the value of considering factors and processes other than collective action in transforming societies, (3) the importance of ideology and its operation through social institutions such as news media, and (4) an imperative to ensure that our research is fully engaged with society in terms of its grounding in social issues, its sensitivity to our own social context as researchers, and in its practices and outcomes.Mood-dependent changes in cognitive controlSaunders, Blairhttps://hdl.handle.net/10023/45032019-04-01T10:41:58Z2014-01-01T00:00:00ZThe symptomatology of depression includes affective and cognitive features. As such,
depression has been associated both with maladaptive concern over emotional material, and
also with general impairments in attentional control. In the current thesis, I investigated the
potential influence of such depression-related dysfunctional emotional processing on a range
of cognitive control abilities, using experimental paradigms containing either neutral or
affective stimuli. In contrast to the hypothesis that depressive symptoms are associated with
generally compromised cognitive control, depression-related impairments were not found on
a range of ‘classic' measures of cognitive control, including error-processing (pre-error
speeding, posterror slowing and error-related ERPs), overriding response conflict (colour-word Stroop interference, conflict adaptation) or more sustained control processes (cued-RT
performance, preparatory ERPs, and maintaining long-term speed-accuracy tradeoffs).
Interestingly, however, differences between groups with low and elevated levels of depressive
symptoms emerged during the performance of emotionally valenced tasks. First, an elevated
depressive symptom group showed a reduced ability to resolve emotional conflict arising
between competing affective representations. When compared with spared performance on
the classic Stroop task, this result suggests that depressive symptoms are associated with a
specific impairment in the ability to regulate emotional distraction. Secondly, an ERP related
to advanced preparation in cued-RT tasks (the CNV), but not those associated with early
perceptual processing (P1, N170), was selectively modulated by negative, but not positive,
task-irrelevant emotional distractors presented during the cue-target interval. This pattern of
ERP results supports a late processing locus of affective attentional bias in depression.
Together, the current results propose that control processes which facilitate the regulation of
emotional material (i.e. over emotional sources of distraction) might be selectively affected
by increased depressive symptoms, suggesting that future work should consider affective
variables when investigating executive control processes in depression.
2014-01-01T00:00:00ZSaunders, BlairThe symptomatology of depression includes affective and cognitive features. As such,
depression has been associated both with maladaptive concern over emotional material, and
also with general impairments in attentional control. In the current thesis, I investigated the
potential influence of such depression-related dysfunctional emotional processing on a range
of cognitive control abilities, using experimental paradigms containing either neutral or
affective stimuli. In contrast to the hypothesis that depressive symptoms are associated with
generally compromised cognitive control, depression-related impairments were not found on
a range of ‘classic' measures of cognitive control, including error-processing (pre-error
speeding, posterror slowing and error-related ERPs), overriding response conflict (colour-word Stroop interference, conflict adaptation) or more sustained control processes (cued-RT
performance, preparatory ERPs, and maintaining long-term speed-accuracy tradeoffs).
Interestingly, however, differences between groups with low and elevated levels of depressive
symptoms emerged during the performance of emotionally valenced tasks. First, an elevated
depressive symptom group showed a reduced ability to resolve emotional conflict arising
between competing affective representations. When compared with spared performance on
the classic Stroop task, this result suggests that depressive symptoms are associated with a
specific impairment in the ability to regulate emotional distraction. Secondly, an ERP related
to advanced preparation in cued-RT tasks (the CNV), but not those associated with early
perceptual processing (P1, N170), was selectively modulated by negative, but not positive,
task-irrelevant emotional distractors presented during the cue-target interval. This pattern of
ERP results supports a late processing locus of affective attentional bias in depression.
Together, the current results propose that control processes which facilitate the regulation of
emotional material (i.e. over emotional sources of distraction) might be selectively affected
by increased depressive symptoms, suggesting that future work should consider affective
variables when investigating executive control processes in depression.The role of facial cues to body size on attractiveness and perceived leadership abilityRe, Daniel E.https://hdl.handle.net/10023/44402019-04-01T10:41:57Z2013-01-01T00:00:00ZFacial appearance has a strong effect on leadership selection. Ratings of
perceived leadership ability from facial images have a pronounced influence on
leadership selection in politics, from low-level municipal elections to the federal
elections of the most powerful countries in the world. Furthermore, ratings of leadership
ability from facial images of business leaders correlate with leadership performance as
measured by profits earned.
Two elements of facial appearance that have reliable effects of perceived
leadership ability are perceived dominance and attractiveness. These cues have been
predictive of leadership choices, both experimentally and in the real-world. Chapters 1
and 2 review research on face components that affect perceived dominance and
attractiveness. Chapter 3 discusses how perceived dominance and attractiveness
influence perception of leadership ability.
Two characteristics that affect both perceived dominance and attractiveness are
height and weight. Chapters 4-9 present empirical studies on two recently-discovered
facial parameters: perceived height (how tall someone appears from their face) and
facial adiposity (a reliable proxy of body mass index that influences perceived weight).
Chapters 4 and 5 demonstrate that these facial parameters alter facial attractiveness.
Chapters 6, 7, and 8 examine how perceived height and facial adiposity influence
perceived leadership ability. Chapter 9 examines how perceived height alters leadership
perception in war and peace contexts. Chapter 10 summarises the empirical research
reported in the thesis and draws conclusions from the findings. Chapter 10 also lists
proposals for future research that could further enhance our knowledge of how facial
cues to perceived body size influence democratic leadership selection.
2013-01-01T00:00:00ZRe, Daniel E.Facial appearance has a strong effect on leadership selection. Ratings of
perceived leadership ability from facial images have a pronounced influence on
leadership selection in politics, from low-level municipal elections to the federal
elections of the most powerful countries in the world. Furthermore, ratings of leadership
ability from facial images of business leaders correlate with leadership performance as
measured by profits earned.
Two elements of facial appearance that have reliable effects of perceived
leadership ability are perceived dominance and attractiveness. These cues have been
predictive of leadership choices, both experimentally and in the real-world. Chapters 1
and 2 review research on face components that affect perceived dominance and
attractiveness. Chapter 3 discusses how perceived dominance and attractiveness
influence perception of leadership ability.
Two characteristics that affect both perceived dominance and attractiveness are
height and weight. Chapters 4-9 present empirical studies on two recently-discovered
facial parameters: perceived height (how tall someone appears from their face) and
facial adiposity (a reliable proxy of body mass index that influences perceived weight).
Chapters 4 and 5 demonstrate that these facial parameters alter facial attractiveness.
Chapters 6, 7, and 8 examine how perceived height and facial adiposity influence
perceived leadership ability. Chapter 9 examines how perceived height alters leadership
perception in war and peace contexts. Chapter 10 summarises the empirical research
reported in the thesis and draws conclusions from the findings. Chapter 10 also lists
proposals for future research that could further enhance our knowledge of how facial
cues to perceived body size influence democratic leadership selection.The role of executive attention in healthy older adults' concurrent walking and countingMaclean, Linda MacArthurhttps://hdl.handle.net/10023/44352019-04-01T10:40:59Z2013-01-01T00:00:00ZCompleting activities of daily life relies on using both cognitive and physical resources
efficiently, but these are affected by age. This may be due either to an age-related reduction
in the resources we have available for carrying out tasks or to a reduction in our ability to use
these resources efficiently. These resources comprise a set of processes called executive
functions (EF), which collectively allow us to plan, initiate and monitor our performance of
activities. Control and allocation of these resources is attributed to a central mechanism,
sometimes called the central executive or executive attention, but the parameters that
determine how resources are allocated are not well understood. Even simple or apparently
automatic activities, such as walking, require attention, meaning that when task demands
increase, for example when walking and speaking on the phone, there is a loss of efficiency
in both tasks. The dual-task (DT) paradigm is an empirical means of examining the way
attentional resources are allocated between two tasks by comparing their performance
together in relation to how well they are carried out singly. Asking people to perform a
cognitive task, such as counting backwards or spelling, while walking provides a reasonably
naturalistic way to examine how flexibly older adults can divide their attention between the
two tasks. Manipulating the demands of the task, either by increasing the difficulty of the
cognitive task or instructing the participants to focus on one task or the other (prioritisation)
should illuminate the strategies they use to allocate their available attention between the two
tasks ask task demands vary. To explore this hypothesis a cohort of physically and
cognitively healthy community-dwelling older adults (mean age = 72.3 years) took part in
three studies. In the first experiment, 72 participants completed 8 single and dual-task
conditions with varying cognitive load (counting back in 3s and 7s) and attention
prioritisation (no prioritisation, prioritising walking and prioritising counting). Instructing the
participants to prioritise walking in the DT when counting back in 7s produced the best
walking and counting performance and this was predicted their score on a standardised
measure of cognitive flexibility. In second part of the study, 68 of the participants were tested
12 months later when there was improvement in both their single and dual-task performances.
There was also decline in concurrent walking and counting performance, but only when
attention was allocated to walking in preference to the cognitive task. Both the improvements
and the decline in performance after the 12-month period were predicted by a standardised
test for EF at T1. In the third study a separate group of older adults (73.2 years) was trained
to walk rhythmically to music, to further investigate the external manipulation of resource-allocation during concurrent walking and counting. Their performances were compared to 2
control groups who did not receive the same intervention procedures. Overall findings from
this doctoral research demonstrate that explicitly manipulating attention-allocation during
concurrent walking and cognitive activity improved healthy older adults’ walking and
counting performance and this was strongly associated with better cognitive flexibility. After
12 months, subtle decline in ability to allocate attention to walking during the DT, when
attentional-demands were high, was also predicted by cognitive flexibility in an EF task.
Together, these findings illuminated the role of executive attention in a rapidly-changing
complex task when the ‘wrong’ prioritisation could result in a fall. Observing healthy older
adults’ cognitive flexibility in allocating attention to walking, when required, revealed that
executive attention was key to the future maintenance of their current functional well-being.
2013-01-01T00:00:00ZMaclean, Linda MacArthurCompleting activities of daily life relies on using both cognitive and physical resources
efficiently, but these are affected by age. This may be due either to an age-related reduction
in the resources we have available for carrying out tasks or to a reduction in our ability to use
these resources efficiently. These resources comprise a set of processes called executive
functions (EF), which collectively allow us to plan, initiate and monitor our performance of
activities. Control and allocation of these resources is attributed to a central mechanism,
sometimes called the central executive or executive attention, but the parameters that
determine how resources are allocated are not well understood. Even simple or apparently
automatic activities, such as walking, require attention, meaning that when task demands
increase, for example when walking and speaking on the phone, there is a loss of efficiency
in both tasks. The dual-task (DT) paradigm is an empirical means of examining the way
attentional resources are allocated between two tasks by comparing their performance
together in relation to how well they are carried out singly. Asking people to perform a
cognitive task, such as counting backwards or spelling, while walking provides a reasonably
naturalistic way to examine how flexibly older adults can divide their attention between the
two tasks. Manipulating the demands of the task, either by increasing the difficulty of the
cognitive task or instructing the participants to focus on one task or the other (prioritisation)
should illuminate the strategies they use to allocate their available attention between the two
tasks ask task demands vary. To explore this hypothesis a cohort of physically and
cognitively healthy community-dwelling older adults (mean age = 72.3 years) took part in
three studies. In the first experiment, 72 participants completed 8 single and dual-task
conditions with varying cognitive load (counting back in 3s and 7s) and attention
prioritisation (no prioritisation, prioritising walking and prioritising counting). Instructing the
participants to prioritise walking in the DT when counting back in 7s produced the best
walking and counting performance and this was predicted their score on a standardised
measure of cognitive flexibility. In second part of the study, 68 of the participants were tested
12 months later when there was improvement in both their single and dual-task performances.
There was also decline in concurrent walking and counting performance, but only when
attention was allocated to walking in preference to the cognitive task. Both the improvements
and the decline in performance after the 12-month period were predicted by a standardised
test for EF at T1. In the third study a separate group of older adults (73.2 years) was trained
to walk rhythmically to music, to further investigate the external manipulation of resource-allocation during concurrent walking and counting. Their performances were compared to 2
control groups who did not receive the same intervention procedures. Overall findings from
this doctoral research demonstrate that explicitly manipulating attention-allocation during
concurrent walking and cognitive activity improved healthy older adults’ walking and
counting performance and this was strongly associated with better cognitive flexibility. After
12 months, subtle decline in ability to allocate attention to walking during the DT, when
attentional-demands were high, was also predicted by cognitive flexibility in an EF task.
Together, these findings illuminated the role of executive attention in a rapidly-changing
complex task when the ‘wrong’ prioritisation could result in a fall. Observing healthy older
adults’ cognitive flexibility in allocating attention to walking, when required, revealed that
executive attention was key to the future maintenance of their current functional well-being.Common HLA alleles associated with health, but not with facial attractivenessCoetzee, VinetBarrett, L.Greeff, J.M.Henzi, S.P.Perrett, David IanWadee, A.A.https://hdl.handle.net/10023/42432023-04-25T23:35:07Z2007-07-01T00:00:00ZThree adaptive hypotheses have been proposed to explain the link between the human leucocyte antigen (HLA) genes, health measures and facial attractiveness: inbreeding avoidance, heterozygote advantage and frequency-dependent selection. This paper reports findings that support a new hypothesis relating HLA to health. We suggest a new method to quantify the level of heterozygosity. HLA heterozygosity did not significantly predict health measures in women, but allele frequency did. Women with more common HLA alleles reported fewer cold and flu bouts per year, fewer illnesses in the previous year and rated themselves healthier than women with rare alleles. To our knowledge, this is the first study to show a positive correlation between HLA allele frequency and general health measures. We propose that certain common HLA alleles confer resistance to prevalent pathogens. Nevertheless, neither HLA heterozygosity nor allele frequency significantly predicted how healthy or attractive men rated the female volunteers. Three non-mutually exclusive explanations are put forward to explain this finding.
This material is based, in part, upon work supported by the National Research Foundation under Grant number 2053809 to JMG.
2007-07-01T00:00:00ZCoetzee, VinetBarrett, L.Greeff, J.M.Henzi, S.P.Perrett, David IanWadee, A.A.Three adaptive hypotheses have been proposed to explain the link between the human leucocyte antigen (HLA) genes, health measures and facial attractiveness: inbreeding avoidance, heterozygote advantage and frequency-dependent selection. This paper reports findings that support a new hypothesis relating HLA to health. We suggest a new method to quantify the level of heterozygosity. HLA heterozygosity did not significantly predict health measures in women, but allele frequency did. Women with more common HLA alleles reported fewer cold and flu bouts per year, fewer illnesses in the previous year and rated themselves healthier than women with rare alleles. To our knowledge, this is the first study to show a positive correlation between HLA allele frequency and general health measures. We propose that certain common HLA alleles confer resistance to prevalent pathogens. Nevertheless, neither HLA heterozygosity nor allele frequency significantly predicted how healthy or attractive men rated the female volunteers. Three non-mutually exclusive explanations are put forward to explain this finding.Emotion recognition in chronic treatment-resistant depression : before and after neurosurgical treatmentGrant, Frazer Alexander Lockharthttps://hdl.handle.net/10023/42132019-04-01T10:41:46Z2013-01-01T00:00:00ZThe neuroanatomical structures underlying Major Depressive
Disorder (MDD) are not fully understood. Invasive treatment options
now exist that target the brain structures associated with MDD.
In part one of this study, the effects of MDD on emotion
processing are being measured and discussed. Emotion processing
was examined in patients with chronic, treatment resistant
depression (n = 15) and a healthy control group (n = 38). Emotion
processing abilities were impaired in the MDD group, especially
those of disgust recognition.
In part two, seven of the fifteen MDD patients that had received
an Anterior Cingulotomy (ACING) and eight of the fifteen MDD
patients that had received a Vagus Nerve Stimulation (VNS) as an
intervention for chronic, treatment resistant depression were
presented with the same series of emotional processing tasks given
in part one. Their post surgical performance was compared with their
pre surgical performance. After surgery, the ACING group showed
decreased emotion processing abilities and the VNS group showed
improvements.
Findings suggest that emotional functions assumed to be
associated with certain neural structures that are adversely affected
in patients with MDD may be responsible for some of the clinical
features of MDD.
2013-01-01T00:00:00ZGrant, Frazer Alexander LockhartThe neuroanatomical structures underlying Major Depressive
Disorder (MDD) are not fully understood. Invasive treatment options
now exist that target the brain structures associated with MDD.
In part one of this study, the effects of MDD on emotion
processing are being measured and discussed. Emotion processing
was examined in patients with chronic, treatment resistant
depression (n = 15) and a healthy control group (n = 38). Emotion
processing abilities were impaired in the MDD group, especially
those of disgust recognition.
In part two, seven of the fifteen MDD patients that had received
an Anterior Cingulotomy (ACING) and eight of the fifteen MDD
patients that had received a Vagus Nerve Stimulation (VNS) as an
intervention for chronic, treatment resistant depression were
presented with the same series of emotional processing tasks given
in part one. Their post surgical performance was compared with their
pre surgical performance. After surgery, the ACING group showed
decreased emotion processing abilities and the VNS group showed
improvements.
Findings suggest that emotional functions assumed to be
associated with certain neural structures that are adversely affected
in patients with MDD may be responsible for some of the clinical
features of MDD.Psychological antecedents of suicidal behaviorCameron, Shrihttps://hdl.handle.net/10023/42122019-07-01T10:04:28Z2013-11-29T00:00:00ZWhile research highlights a number of risk factors for suicide, not all individuals displaying these characteristics will go on to attempt suicide. Depressed mood is a proximal indicator of suicide, with deterioration in already depressed mood increasing the likelihood of a suicide attempt. The overall aim of this thesis was to empirically test the Cognitive Model of Suicide by Wenzel and Beck (2008). This model proposes that each of the three components, dispositional vulnerabilities, mood disturbance and suicide related cognitions, may influence each other to enhance the propensity for a suicidal crisis. The thesis starts by examining the relationship between two personality characteristics (neuroticism and trait aggression) and current depressed mood, and then focuses on the relationship between suicidality and current depressed mood. Although autobiographical memories have been implied as a possible risk factor for suicidality, meta-analytical studies have highlighted discrepancies between sampling techniques which may limit interpretablity. Therefore, the first series of studies aimed to establish a protocol for assessing autobiographical memories. The second and third series of studies aimed to investigate whether the relationships between current depressed mood and specific personality factors (neuroticism and trait aggression) were indirectly influenced by other known risk factors that may affect cognitive processing of information (rumination, overgenerality, impulsivity). Moreover, these studies aimed to determine whether the same cognitive processing factors effected current depressed mood in non-suicidal and suicide attempt groups. The final series of studies aimed to determine whether these risk factors (neuroticism, trait aggression, brooding, impulsivity, and overgenerality) mediated the relationship between suicidality and current depressed mood. Findings indicated that compared to the non-suicidal group, individuals in the suicide attempt group was more likely to be influenced by the effects of trait aggression and brooding, and that the combination of these factors were positively associated with current depressed mood. In contrast, neuroticism and impulsivity appeared to influence individuals who had experienced suicidal ideation more than individuals who report never having suicidal thoughts or attempting suicide. Compared to the non-suicidal group, however, neuroticism and impulsivity did not show a significant association for current depressed mood in the suicidal ideation group. Findings supported the Interacting Sub-Systems model and are discussed in relation to the Cognitive Model of Suicide model.
2013-11-29T00:00:00ZCameron, ShriWhile research highlights a number of risk factors for suicide, not all individuals displaying these characteristics will go on to attempt suicide. Depressed mood is a proximal indicator of suicide, with deterioration in already depressed mood increasing the likelihood of a suicide attempt. The overall aim of this thesis was to empirically test the Cognitive Model of Suicide by Wenzel and Beck (2008). This model proposes that each of the three components, dispositional vulnerabilities, mood disturbance and suicide related cognitions, may influence each other to enhance the propensity for a suicidal crisis. The thesis starts by examining the relationship between two personality characteristics (neuroticism and trait aggression) and current depressed mood, and then focuses on the relationship between suicidality and current depressed mood. Although autobiographical memories have been implied as a possible risk factor for suicidality, meta-analytical studies have highlighted discrepancies between sampling techniques which may limit interpretablity. Therefore, the first series of studies aimed to establish a protocol for assessing autobiographical memories. The second and third series of studies aimed to investigate whether the relationships between current depressed mood and specific personality factors (neuroticism and trait aggression) were indirectly influenced by other known risk factors that may affect cognitive processing of information (rumination, overgenerality, impulsivity). Moreover, these studies aimed to determine whether the same cognitive processing factors effected current depressed mood in non-suicidal and suicide attempt groups. The final series of studies aimed to determine whether these risk factors (neuroticism, trait aggression, brooding, impulsivity, and overgenerality) mediated the relationship between suicidality and current depressed mood. Findings indicated that compared to the non-suicidal group, individuals in the suicide attempt group was more likely to be influenced by the effects of trait aggression and brooding, and that the combination of these factors were positively associated with current depressed mood. In contrast, neuroticism and impulsivity appeared to influence individuals who had experienced suicidal ideation more than individuals who report never having suicidal thoughts or attempting suicide. Compared to the non-suicidal group, however, neuroticism and impulsivity did not show a significant association for current depressed mood in the suicidal ideation group. Findings supported the Interacting Sub-Systems model and are discussed in relation to the Cognitive Model of Suicide model.Receiving post-conflict affiliation from the enemy's friend reconciles former opponentsWittig, Roman MartinBoesch, Christophehttps://hdl.handle.net/10023/41672022-04-07T15:30:22Z2010-11-15T00:00:00ZThe adaptive function of bystander initiated post-conflict affiliation (also: consolation & appeasement) has been debated for 30 years. Three influential hypotheses compete for the most likely explanation but have not previously been tested with a single data set. The consolation hypothesis argues that bystander affiliation calms the victim and reduces their stress levels. The self-protection hypothesis proposes that a bystander offers affiliation to either opponent to protect himself from redirected aggression by this individual. The relationship-repair hypothesis suggests a bystander can substitute for a friend to reconcile the friend with the friend’s former opponent. Here, we contrast all three hypotheses and tested their predictions with data on wild chimpanzees (Pan troglodytes verus) of the Taı¨ National Park, Coˆ te d’Ivoire. We examined the first and second post-conflict interactions with respect to both the dyadic and triadic relationships between the bystander and the two opponents. Results showed that female bystanders offered affiliation to their aggressor friends and the victims of their friends, while male bystanders offered affiliation to their victim friends and the aggressors of their friends. For both sexes, bystander affiliation resulted in a subsequent interaction pattern that is expected for direct reconciliation. Bystander affiliation offered to the opponent’s friend was more likely to lead to affiliation among opponents in their subsequent interaction. Also, tolerance levels among former opponents were reset to normal levels. In conclusion, this study provides strong evidence for the relationship-repair hypothesis, moderate evidence for the consolation hypothesis and no evidence for the self-protection hypothesis. Furthermore, that bystanders can repair a relationship on behalf of their friend indicates that recipient chimpanzees are aware of the relationships between others, even when they are not kin. This presents a mechanism through which chimpanzees may gain benefits from social knowledge.
2010-11-15T00:00:00ZWittig, Roman MartinBoesch, ChristopheThe adaptive function of bystander initiated post-conflict affiliation (also: consolation & appeasement) has been debated for 30 years. Three influential hypotheses compete for the most likely explanation but have not previously been tested with a single data set. The consolation hypothesis argues that bystander affiliation calms the victim and reduces their stress levels. The self-protection hypothesis proposes that a bystander offers affiliation to either opponent to protect himself from redirected aggression by this individual. The relationship-repair hypothesis suggests a bystander can substitute for a friend to reconcile the friend with the friend’s former opponent. Here, we contrast all three hypotheses and tested their predictions with data on wild chimpanzees (Pan troglodytes verus) of the Taı¨ National Park, Coˆ te d’Ivoire. We examined the first and second post-conflict interactions with respect to both the dyadic and triadic relationships between the bystander and the two opponents. Results showed that female bystanders offered affiliation to their aggressor friends and the victims of their friends, while male bystanders offered affiliation to their victim friends and the aggressors of their friends. For both sexes, bystander affiliation resulted in a subsequent interaction pattern that is expected for direct reconciliation. Bystander affiliation offered to the opponent’s friend was more likely to lead to affiliation among opponents in their subsequent interaction. Also, tolerance levels among former opponents were reset to normal levels. In conclusion, this study provides strong evidence for the relationship-repair hypothesis, moderate evidence for the consolation hypothesis and no evidence for the self-protection hypothesis. Furthermore, that bystanders can repair a relationship on behalf of their friend indicates that recipient chimpanzees are aware of the relationships between others, even when they are not kin. This presents a mechanism through which chimpanzees may gain benefits from social knowledge.Interactions between luminance and colour signals : effects on shapeClery, StephaneBloj, MarinaHarris, Juliehttps://hdl.handle.net/10023/38612022-04-26T08:30:12Z2013-04-18T00:00:00ZAlthough luminance and color are thought to be processed independently at early stages of visual processing, there is evidence that they interact at later stages. For example, chromatic information has been shown to enhance or suppress depth from luminance depending on whether chromatic edges are aligned or orthogonal with luminance edges. Here we explored more generally how chromatic information interacts with luminance information that specifies shape from shading. Using a depth-matching task, we measured perceived depth in sinusoidal and square-wave gratings (specifying close-to sinusoidal and triangle-wave depth profiles, respectively) in three conditions. In the first, as we varied luminance contrast in the presence of an orthogonal chromatic grating, perceived depth increased (consistent with classical shape from shading). When we held the luminance at a fixed contrast and varied the chromatic grating in the other two conditions (orthogonal or aligned), we found large and inconsistent individual differences. Some participants exhibited the expected pattern of enhancement and suppression, but most did not, either for the sinusoidal or square-wave stimuli. Our results cast doubt on the idea that the interaction demonstrates a single high-level heuristic linked to depth perception. Instead, we speculate that interactions are more likely due to early cross-channel masking
This research was supported by the Engineering and Physical Sciences Research Council (EPSRC).
2013-04-18T00:00:00ZClery, StephaneBloj, MarinaHarris, JulieAlthough luminance and color are thought to be processed independently at early stages of visual processing, there is evidence that they interact at later stages. For example, chromatic information has been shown to enhance or suppress depth from luminance depending on whether chromatic edges are aligned or orthogonal with luminance edges. Here we explored more generally how chromatic information interacts with luminance information that specifies shape from shading. Using a depth-matching task, we measured perceived depth in sinusoidal and square-wave gratings (specifying close-to sinusoidal and triangle-wave depth profiles, respectively) in three conditions. In the first, as we varied luminance contrast in the presence of an orthogonal chromatic grating, perceived depth increased (consistent with classical shape from shading). When we held the luminance at a fixed contrast and varied the chromatic grating in the other two conditions (orthogonal or aligned), we found large and inconsistent individual differences. Some participants exhibited the expected pattern of enhancement and suppression, but most did not, either for the sinusoidal or square-wave stimuli. Our results cast doubt on the idea that the interaction demonstrates a single high-level heuristic linked to depth perception. Instead, we speculate that interactions are more likely due to early cross-channel maskingInvestigating the role of cognition in nest construction in birdsMuth, Felicityhttps://hdl.handle.net/10023/38202019-04-01T10:41:56Z2013-01-01T00:00:00ZNest building in birds has long been assumed to be a behaviour that is not learned, despite suggestive evidence to the contrary. In this thesis I investigated the role of learning in nest building in birds. I focused primarily on the choice of nest material made by zebra finches, in particular between two or more colours of nesting material. Using this aspect of behaviour, I found that adult nest building birds changed their preference for a particular colour of nesting material depending on their own nesting and breeding experience: males that built a nest using material of their less preferred colour later preferred that colour following a successful breeding attempt in that nest. In contrast to this role for learning in adults, in two other experiments I found no evidence that juvenile birds learned about the nest from which they had fledged or that birds learned about what material to nest with from conspecifics. Using wild Southern masked weavers, I also addressed variability in a particular aspect of nest building: the attachment of the very first blade of grass knotted onto a branch. I found that birds did not construct the same attachment each time they did it, even when building at the same location, but that males generally used more loops in their attachments as they built more nests, and when using longer pieces of grass. Finally, I tested zebra finches on a nest building ‘task’, using a paradigm often used to test cognitive abilities among tool-users. Birds were presented with two lengths of nest material, one of which was more appropriate for one of two sizes of nest box entrance. I found that nesting birds could choose the appropriate length of material and that the birds’ handling of material and their choice of material changed with experience. Taking these results together, it seems that there is a greater role for learning in nest construction than is generally acknowledged and that nest building might involve the same underlying cognitive processes as tool manufacture and use.
2013-01-01T00:00:00ZMuth, FelicityNest building in birds has long been assumed to be a behaviour that is not learned, despite suggestive evidence to the contrary. In this thesis I investigated the role of learning in nest building in birds. I focused primarily on the choice of nest material made by zebra finches, in particular between two or more colours of nesting material. Using this aspect of behaviour, I found that adult nest building birds changed their preference for a particular colour of nesting material depending on their own nesting and breeding experience: males that built a nest using material of their less preferred colour later preferred that colour following a successful breeding attempt in that nest. In contrast to this role for learning in adults, in two other experiments I found no evidence that juvenile birds learned about the nest from which they had fledged or that birds learned about what material to nest with from conspecifics. Using wild Southern masked weavers, I also addressed variability in a particular aspect of nest building: the attachment of the very first blade of grass knotted onto a branch. I found that birds did not construct the same attachment each time they did it, even when building at the same location, but that males generally used more loops in their attachments as they built more nests, and when using longer pieces of grass. Finally, I tested zebra finches on a nest building ‘task’, using a paradigm often used to test cognitive abilities among tool-users. Birds were presented with two lengths of nest material, one of which was more appropriate for one of two sizes of nest box entrance. I found that nesting birds could choose the appropriate length of material and that the birds’ handling of material and their choice of material changed with experience. Taking these results together, it seems that there is a greater role for learning in nest construction than is generally acknowledged and that nest building might involve the same underlying cognitive processes as tool manufacture and use.A behavioural analysis of "choking" in self-paced skillsJackson, Robin C.https://hdl.handle.net/10023/37142019-04-01T10:42:06Z1998-01-01T00:00:00ZThis thesis is about "choking" in self-paced skills. Choking refers to ''the
occurrence of inferior performance despite striving and incentives for superior
performance" (Baumeister and Steinhilber, 1986, p. 361). Self-paced skills are skills in
which performance is initiated by the athlete. This research set out to investigate the
cause of choking in self-paced skills within the theoretical framework of behaviour
analysis. The main focus of the research relates to the distinction between behaviour
under the control of verbal antecedents (rule-governed behaviour) and behaviour that is
shaped by its consequences (contingency-shaped behaviour).
It was originally hypothesised that the insensitivity of rule-governed behaviour
to changes in the contingencies of reinforcement could he beneficial in situations where
these changes led to greater performance pressure. Specifically, it was predicted that
performance under the control of verbal antecedents would be less susceptible to
choking. In the first experiment, no support was found for the hypothesis and,
furthermore, rule-governed performance appeared to be inferior to contingency-shaped
performance in the early stages of acquisition.
In light of these results, and after a detailed examination of the behaviour
analysis distinction between these two forms of behaviour, evidence was presented
which suggested that verbal control of the topography, or form, of behaviour would be
likely to disrupt performance in self-paced skills. In subsequent experiments, it was
found that using simple verbal cues was an effective means of preventing choking under
pressure. It was hypothesised that the function of these cues was in preventing
reinvestment of too many technical instructions in the moments before performance
initiation. The assumptions upon which the reinvestment theory of choking is based
were also examined with results providing general support for the theory but also
suggesting that it needs to be refined to account for verbal antecedents that do not
disrupt performance.
1998-01-01T00:00:00ZJackson, Robin C.This thesis is about "choking" in self-paced skills. Choking refers to ''the
occurrence of inferior performance despite striving and incentives for superior
performance" (Baumeister and Steinhilber, 1986, p. 361). Self-paced skills are skills in
which performance is initiated by the athlete. This research set out to investigate the
cause of choking in self-paced skills within the theoretical framework of behaviour
analysis. The main focus of the research relates to the distinction between behaviour
under the control of verbal antecedents (rule-governed behaviour) and behaviour that is
shaped by its consequences (contingency-shaped behaviour).
It was originally hypothesised that the insensitivity of rule-governed behaviour
to changes in the contingencies of reinforcement could he beneficial in situations where
these changes led to greater performance pressure. Specifically, it was predicted that
performance under the control of verbal antecedents would be less susceptible to
choking. In the first experiment, no support was found for the hypothesis and,
furthermore, rule-governed performance appeared to be inferior to contingency-shaped
performance in the early stages of acquisition.
In light of these results, and after a detailed examination of the behaviour
analysis distinction between these two forms of behaviour, evidence was presented
which suggested that verbal control of the topography, or form, of behaviour would be
likely to disrupt performance in self-paced skills. In subsequent experiments, it was
found that using simple verbal cues was an effective means of preventing choking under
pressure. It was hypothesised that the function of these cues was in preventing
reinvestment of too many technical instructions in the moments before performance
initiation. The assumptions upon which the reinvestment theory of choking is based
were also examined with results providing general support for the theory but also
suggesting that it needs to be refined to account for verbal antecedents that do not
disrupt performance.Female putty-nosed monkeys use experimentally altered contextual information to disambiguate the cause of male alarm callsArnold, KateZuberbuehler, Klaushttps://hdl.handle.net/10023/36742023-04-18T09:47:54Z2013-06-05T00:00:00ZMany animal vocal signals are given in a wide range of contexts which can sometimes have little in common. Yet, to respond adaptively, listeners must find ways to identify the cause of a signal, or at least rule out alternatives. Here, we investigate the nature of this process in putty-nosed monkeys, a forest primate. In this species, adult males have a very restricted repertoire of vocalizations which are given in response to a wide variety of events occurring under conditions of limited visibility. We carried out a series of field playback experiments on females (N = 6) in a habituated group in Gashaka Gumti National Park, Nigeria, in which male alarm/loud calls were presented either alone, or following acoustic information that simulated the occurrence of natural disturbances. We demonstrate that listeners appear to integrate contextual information in order to distinguish among possible causes of calls. We conclude that, in many cases, pragmatic aspects of communication play a crucial role in call interpretation and place a premium on listeners' abilities to integrate information from different sources.
Funding was provided by The Leverhulme Trust (http://www.leverhulme.ac.uk/). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
2013-06-05T00:00:00ZArnold, KateZuberbuehler, KlausMany animal vocal signals are given in a wide range of contexts which can sometimes have little in common. Yet, to respond adaptively, listeners must find ways to identify the cause of a signal, or at least rule out alternatives. Here, we investigate the nature of this process in putty-nosed monkeys, a forest primate. In this species, adult males have a very restricted repertoire of vocalizations which are given in response to a wide variety of events occurring under conditions of limited visibility. We carried out a series of field playback experiments on females (N = 6) in a habituated group in Gashaka Gumti National Park, Nigeria, in which male alarm/loud calls were presented either alone, or following acoustic information that simulated the occurrence of natural disturbances. We demonstrate that listeners appear to integrate contextual information in order to distinguish among possible causes of calls. We conclude that, in many cases, pragmatic aspects of communication play a crucial role in call interpretation and place a premium on listeners' abilities to integrate information from different sources.Cognition in inter-group relations : the effect of group membership on theory of mind and its precursorsMcClung, Jenniferhttps://hdl.handle.net/10023/36572023-10-04T02:05:56Z2012-01-01T00:00:00ZSocial categorization based on group membership has a significant and broad
influence on behaviour (Turner, Hogg, Oakes, Reicher, & Wetherell, 1987). People
perceived as being of the same group, ‘in-group’ members, are accorded all kinds of special treatment, such as the tendency to reward them over out-group members (Tajfel, Billig, Bundy, & Flament, 1971). At the other extreme is denigration based solely on a person’s status as ‘out-group’ member, sometimes even to the point of perceiving that person as less human than fellow in-group members, a phenomenon termed dehumanisation (Leyens et al., 2001). Historic examples of dehumanisation are abundant, such as the extermination of Jews
in Nazi Germany. What is less well understood, however, are the cognitive processes involved in these inter-group phenomena. How can a normal human being, with fully functioning cognitive faculties, come to not only view another person as sub-human but also to act on such irrational beliefs? One cognitive ability that, according to theory, plays a pivotal role in every human social interaction is the ability to attribute mental states to others, which enables humans to construct a theory of the minds they interact with. Having a ‘theory of mind’ allows an individual to interpret and predict behaviour in terms of underlying mental states (Premack & Woodruff, 1978). It is widely acknowledged that theory of mind is of fundamental importance to human social interactions (Baron-Cohen, Tager-Flusberg, & Cohen, 2000).
For example, the ability to understand others’ intentions and goals allows humans to
participate in collaborative action with shared ends, a hallmark capacity required for human social structures such as governments and economic systems (Tomasello, Carpenter, Call, Behne, & Moll, 2005). Given the importance of theory of mind to daily human life, a critical question thus is when and how theory of mind is actually used, especially in inter-group contexts such as those previously mentioned. While the developing, abnormal, and non-human theory of mind have been thoroughly investigated, much less is known about how normal adults deploy their theory of mind in actual social situations, including in situations of
inter-group conflict.
The present thesis has the primary aim of understanding how group membership
affects the quotidian functioning of theory of mind and the social cognitive abilities that form its foundation, representation of intentionality and more basic processes of social learning.
To this end, I will examine the effects of group membership on normal adults’ theory of mind usage (study 1). I will then go on to look at the deeper effects of group membership on social cognition, particularly its effect on some of the building blocks of theory of mind, representation of intentionality and basic social learning. To this end, I will first look at how
intentionality is represented as a function of a person’s group membership with and without social competition (studies 2 & 3), and on how perceptions of group membership and social power impact basic social learning processes (studies 4 & 5). This process will elucidate the degree to which social cognition processes, from theory of mind down to its basic cognitive
roots, are affected by perceptions of group membership. A secondary goal is to generate
more informed hypotheses about the nature of the cognitive mechanisms underlying group-
based social phenomena, such as dehumanisation.
2012-01-01T00:00:00ZMcClung, JenniferSocial categorization based on group membership has a significant and broad
influence on behaviour (Turner, Hogg, Oakes, Reicher, & Wetherell, 1987). People
perceived as being of the same group, ‘in-group’ members, are accorded all kinds of special treatment, such as the tendency to reward them over out-group members (Tajfel, Billig, Bundy, & Flament, 1971). At the other extreme is denigration based solely on a person’s status as ‘out-group’ member, sometimes even to the point of perceiving that person as less human than fellow in-group members, a phenomenon termed dehumanisation (Leyens et al., 2001). Historic examples of dehumanisation are abundant, such as the extermination of Jews
in Nazi Germany. What is less well understood, however, are the cognitive processes involved in these inter-group phenomena. How can a normal human being, with fully functioning cognitive faculties, come to not only view another person as sub-human but also to act on such irrational beliefs? One cognitive ability that, according to theory, plays a pivotal role in every human social interaction is the ability to attribute mental states to others, which enables humans to construct a theory of the minds they interact with. Having a ‘theory of mind’ allows an individual to interpret and predict behaviour in terms of underlying mental states (Premack & Woodruff, 1978). It is widely acknowledged that theory of mind is of fundamental importance to human social interactions (Baron-Cohen, Tager-Flusberg, & Cohen, 2000).
For example, the ability to understand others’ intentions and goals allows humans to
participate in collaborative action with shared ends, a hallmark capacity required for human social structures such as governments and economic systems (Tomasello, Carpenter, Call, Behne, & Moll, 2005). Given the importance of theory of mind to daily human life, a critical question thus is when and how theory of mind is actually used, especially in inter-group contexts such as those previously mentioned. While the developing, abnormal, and non-human theory of mind have been thoroughly investigated, much less is known about how normal adults deploy their theory of mind in actual social situations, including in situations of
inter-group conflict.
The present thesis has the primary aim of understanding how group membership
affects the quotidian functioning of theory of mind and the social cognitive abilities that form its foundation, representation of intentionality and more basic processes of social learning.
To this end, I will examine the effects of group membership on normal adults’ theory of mind usage (study 1). I will then go on to look at the deeper effects of group membership on social cognition, particularly its effect on some of the building blocks of theory of mind, representation of intentionality and basic social learning. To this end, I will first look at how
intentionality is represented as a function of a person’s group membership with and without social competition (studies 2 & 3), and on how perceptions of group membership and social power impact basic social learning processes (studies 4 & 5). This process will elucidate the degree to which social cognition processes, from theory of mind down to its basic cognitive
roots, are affected by perceptions of group membership. A secondary goal is to generate
more informed hypotheses about the nature of the cognitive mechanisms underlying group-
based social phenomena, such as dehumanisation.Spatial cognition in three dimensionsFlores Abreu, Ileana Nurihttps://hdl.handle.net/10023/36512019-04-01T10:41:00Z2013-01-01T00:00:00ZTo date, most studies of spatial learning have been conducted in the horizontal plane,
with few addressing the vertical dimension. I aimed to investigate learning of 3-D
locations by wild, free-living hummingbirds and compare them with rats. In my first
experiment, I found that hummingbirds can encode a 3-D rewarded location after a
single visit. Using a one-dimensional array, I then found that the birds more readily
learned a location in a horizontal than in a vertical linear array. However, the ease of
learning was a product not only of the orientation of the array but also of its spacing
scale. By the end of training, hummingbirds visited the central rewarded flower and
the two adjacent flowers more than they visited the distal flowers for all arrays.
However, when the array was horizontal and the flowers spaced 30 cm apart, they
learned the absolute location of the rewarded flower. In a diagonal array birds
learned the 2-D reward location but they chose at random when tested on a vertically
or horizontally oriented array. However, when birds trained in the diagonal array
were tested on a 180° rotated diagonal array they chose the flower with the same
horizontal component as the rewarded flower rather than with the flower with the
same vertical component. Finally in order to compare the spatial learning of animals
that move in volumes with those who move in two dimensions I trained
hummingbirds and rats to a rewarded location in a cubic maze. Although both
hummingbirds and rats learned a 3-D location within a cubic maze, hummingbirds
appeared to learn the rewarded location as a 3-D coordinate while rats seemed to
learn the vertical and horizontal component of the 3-D location independently. In
addition, hummingbirds were more accurate in the vertical and rats in the horizontal,
which is consistent with their type of locomotion. More experiments in volumetric, terrestrial and climbing animals are needed in order to determine whether the
contrasting search strategies and learning accuracies constitute adaptations to
particular spatial niches.
2013-01-01T00:00:00ZFlores Abreu, Ileana NuriTo date, most studies of spatial learning have been conducted in the horizontal plane,
with few addressing the vertical dimension. I aimed to investigate learning of 3-D
locations by wild, free-living hummingbirds and compare them with rats. In my first
experiment, I found that hummingbirds can encode a 3-D rewarded location after a
single visit. Using a one-dimensional array, I then found that the birds more readily
learned a location in a horizontal than in a vertical linear array. However, the ease of
learning was a product not only of the orientation of the array but also of its spacing
scale. By the end of training, hummingbirds visited the central rewarded flower and
the two adjacent flowers more than they visited the distal flowers for all arrays.
However, when the array was horizontal and the flowers spaced 30 cm apart, they
learned the absolute location of the rewarded flower. In a diagonal array birds
learned the 2-D reward location but they chose at random when tested on a vertically
or horizontally oriented array. However, when birds trained in the diagonal array
were tested on a 180° rotated diagonal array they chose the flower with the same
horizontal component as the rewarded flower rather than with the flower with the
same vertical component. Finally in order to compare the spatial learning of animals
that move in volumes with those who move in two dimensions I trained
hummingbirds and rats to a rewarded location in a cubic maze. Although both
hummingbirds and rats learned a 3-D location within a cubic maze, hummingbirds
appeared to learn the rewarded location as a 3-D coordinate while rats seemed to
learn the vertical and horizontal component of the 3-D location independently. In
addition, hummingbirds were more accurate in the vertical and rats in the horizontal,
which is consistent with their type of locomotion. More experiments in volumetric, terrestrial and climbing animals are needed in order to determine whether the
contrasting search strategies and learning accuracies constitute adaptations to
particular spatial niches.On the perception of monocular regions in binocular scenesZeiner, Katharina Mariahttps://hdl.handle.net/10023/36502023-06-27T02:05:00Z2012-01-01T00:00:00ZOur two forward facing eyes supply the visual system with slightly different
versions of the world around us. These slight differences in the two retinal
images are used to obtain depth information about a visual scene.
Conventionally, it has been assumed that points in one retinal image that do
not have corresponding points in the other image are treated as noise.
However, if one object is partially occluded by another, monocular points and
regions occur. While it is, by now, established that we do not ignore
geometrically plausible monocular points and regions, we know much less
about our percept of such regions. So far it has not been studied how our
percept of monocular regions compares to that of binocular regions and how
well we are able to use the information contained in them.
In this thesis I explore our percept of such monocular regions and ask how we
treat them in relation to their binocular surround. Using classical
psychophysical methods as well as reaction-times and eye-tracking data, I find
that we are perfectly capable of using monocular regions to interact with them
and to arrive at a stable, seemingly complete percept of them. Sometimes our
performance even benefts from the presence of a monocular region. However,
this breaks down when we are asked to integrate the information contained in
monocular regions with information in binocular regions.
The experiments in this thesis show that even though we do not ignore
monocular regions and can, if we have to, interact with them, we show a strong
preference towards relying on binocular information when given the option.
2012-01-01T00:00:00ZZeiner, Katharina MariaOur two forward facing eyes supply the visual system with slightly different
versions of the world around us. These slight differences in the two retinal
images are used to obtain depth information about a visual scene.
Conventionally, it has been assumed that points in one retinal image that do
not have corresponding points in the other image are treated as noise.
However, if one object is partially occluded by another, monocular points and
regions occur. While it is, by now, established that we do not ignore
geometrically plausible monocular points and regions, we know much less
about our percept of such regions. So far it has not been studied how our
percept of monocular regions compares to that of binocular regions and how
well we are able to use the information contained in them.
In this thesis I explore our percept of such monocular regions and ask how we
treat them in relation to their binocular surround. Using classical
psychophysical methods as well as reaction-times and eye-tracking data, I find
that we are perfectly capable of using monocular regions to interact with them
and to arrive at a stable, seemingly complete percept of them. Sometimes our
performance even benefts from the presence of a monocular region. However,
this breaks down when we are asked to integrate the information contained in
monocular regions with information in binocular regions.
The experiments in this thesis show that even though we do not ignore
monocular regions and can, if we have to, interact with them, we show a strong
preference towards relying on binocular information when given the option.Is it only specificity? : an investigation into the relationship between autobiographical memory and social problem-solvingDennis, Ashleyhttps://hdl.handle.net/10023/36352019-04-01T10:41:29Z2012-01-01T00:00:00ZResearch suggests that deficits in retrieving specific autobiographical memories
(ABMs) relate to deficits in social problem solving (SPS). Williams (1996) proposes
depressed individuals have deficits in SPS because of difficulty accessing relevant
information stored in specific ABMs. This thesis investigated the relationship between
SPS and ABM. First, it explored a new version of the Means End Problem Solving task
(MEPS; Platt, Spivack, & Bloom, 1975), which incorporates a wider range of social
problems. Utilizing the MEPS, it examined multi-dimensional SPS across the mood
spectrum. Chapters 3 and 5 indicated that depression is associated with general SPS
deficits. However, Chapters 4, 5, and 6 demonstrated that dysphoria is not related to SPS
deficits. Next, the thesis examined the relationship between specific ABM retrieval
during SPS and SPS performance. Chapter 4 attempted to increase specificity of ABM
through an imagery manipulation but was unsuccessful. Furthermore, specificity did not
relate to SPS performance in Chapters 4, 5, and 6. Additionally, it explored
characteristics beyond specificity that may be important to SPS. Although Chapter 5
reported differences in the memory characteristics between the control, dysphoric, and depressed groups, none of the characteristics in Chapters 5 and 6 related to SPS. Chapter 6 also found that individuals who reported more automatically retrieving memories performed better at SPS. Chapter 6 examined the relationship between intrusive memories and SPS and found that the more individuals reported memory intrusions, avoided and had negative appraisals of the intrusions over the past week, the poorer they were at SPS. This thesis demonstrates that specificity is not a fundamental component of SPS performance. Instead, generating specific memories and SPS may both rely on effectively utilizing the ABM structure. The thesis emphasizes the importance of exploring mode of retrieval in the relationship between ABM and SPS as well as the relationship between intrusive memories and SPS.
2012-01-01T00:00:00ZDennis, AshleyResearch suggests that deficits in retrieving specific autobiographical memories
(ABMs) relate to deficits in social problem solving (SPS). Williams (1996) proposes
depressed individuals have deficits in SPS because of difficulty accessing relevant
information stored in specific ABMs. This thesis investigated the relationship between
SPS and ABM. First, it explored a new version of the Means End Problem Solving task
(MEPS; Platt, Spivack, & Bloom, 1975), which incorporates a wider range of social
problems. Utilizing the MEPS, it examined multi-dimensional SPS across the mood
spectrum. Chapters 3 and 5 indicated that depression is associated with general SPS
deficits. However, Chapters 4, 5, and 6 demonstrated that dysphoria is not related to SPS
deficits. Next, the thesis examined the relationship between specific ABM retrieval
during SPS and SPS performance. Chapter 4 attempted to increase specificity of ABM
through an imagery manipulation but was unsuccessful. Furthermore, specificity did not
relate to SPS performance in Chapters 4, 5, and 6. Additionally, it explored
characteristics beyond specificity that may be important to SPS. Although Chapter 5
reported differences in the memory characteristics between the control, dysphoric, and depressed groups, none of the characteristics in Chapters 5 and 6 related to SPS. Chapter 6 also found that individuals who reported more automatically retrieving memories performed better at SPS. Chapter 6 examined the relationship between intrusive memories and SPS and found that the more individuals reported memory intrusions, avoided and had negative appraisals of the intrusions over the past week, the poorer they were at SPS. This thesis demonstrates that specificity is not a fundamental component of SPS performance. Instead, generating specific memories and SPS may both rely on effectively utilizing the ABM structure. The thesis emphasizes the importance of exploring mode of retrieval in the relationship between ABM and SPS as well as the relationship between intrusive memories and SPS.Sex differences in interpretation bias and interpersonal difficulties in adolescence and young adulthoodGluck, Rachel L.https://hdl.handle.net/10023/36302019-07-01T10:03:31Z2013-06-25T00:00:00ZFemales are more likely to become depressed and experience social anxiety than are males, and this sex difference emerges during adolescence. A difference in interpretation of ambiguous social scenarios has been posited as a potential causal factor of the sex differences in mood disorders. Females are also thought to place a higher value on social relationships than are males, which may cause them to view interpersonal relationships as more difficult, further affecting their interpretations of ambiguous social events. To test these hypotheses, differences in interpretation of ambiguous events and perception of interpersonal difficulty were measured using the AIBQ in adolescents (aged 12-15) and young adults (22-25). The participants also rated the level of perceived difficulty of different interpersonal relationships using the QIDA, such as romantic, peer, family, etc. Results showed that females were more likely than males to have negative explanations come to mind for ambiguous social and nonsocial scenarios, and had more negative beliefs than males about ambiguous social scenarios. Adolescents were more negative in belief for social events than for nonsocial events, and were more negative in belief for social scenarios than were adults. All participants had more positive interpretations for nonsocial scenarios than social. No sex or age differences in positive interpretations or interpersonal difficulties were found. Future studies could track the changes as adolescents age and transition into young adulthood.
2013-06-25T00:00:00ZGluck, Rachel L.Females are more likely to become depressed and experience social anxiety than are males, and this sex difference emerges during adolescence. A difference in interpretation of ambiguous social scenarios has been posited as a potential causal factor of the sex differences in mood disorders. Females are also thought to place a higher value on social relationships than are males, which may cause them to view interpersonal relationships as more difficult, further affecting their interpretations of ambiguous social events. To test these hypotheses, differences in interpretation of ambiguous events and perception of interpersonal difficulty were measured using the AIBQ in adolescents (aged 12-15) and young adults (22-25). The participants also rated the level of perceived difficulty of different interpersonal relationships using the QIDA, such as romantic, peer, family, etc. Results showed that females were more likely than males to have negative explanations come to mind for ambiguous social and nonsocial scenarios, and had more negative beliefs than males about ambiguous social scenarios. Adolescents were more negative in belief for social events than for nonsocial events, and were more negative in belief for social scenarios than were adults. All participants had more positive interpretations for nonsocial scenarios than social. No sex or age differences in positive interpretations or interpersonal difficulties were found. Future studies could track the changes as adolescents age and transition into young adulthood.From family metaphor to national attachment? a social identity approach towards framing nationhoodLauenstein, Oliverhttps://hdl.handle.net/10023/36272019-07-01T10:08:38Z2013-06-25T00:00:00ZThe central question of this thesis is: “How can people be mobilised to feel strongly attached to or invest into their nations?” Following a review of literature on the psychology of nationhood, a social identity approach towards national attachment is suggested. The possibility of the family metaphor (e.g. fatherland) as a rhetorical device anchoring the nation in filial qualities (e.g. belonging) is discussed. In the first study, establishing the general prevalence of family metaphors and aiming to test their use as a means of mobilisation, the content of language corpora, speeches, parliamentary debates and national anthems is analysed. The results demonstrate frequent use, especially in connection to mobilisation (e.g. in speeches). Study II tests whether merely linking a stimulus to a family metaphor will elicit a positive response and increase national identification. It does so by presenting a student sample (n = 149) with a neutral picture stimulus with different titles including family terms and family metaphors; no effects of any particular picture title on national identity emerged, but a considerable share of participants provided negative Nazi-related associations when primed with ‘fatherland’. Given the apparent relevance of meaning, the third study employed a word association task to provide a more in-depth account of German (n = 119) and British students’ (n =138) common associations for family metaphors, confirming that some participants associate them with a negative past (e.g. WW II) or negative politics (e.g. nationalism). In an attempt to avoid the impact of said negative associations, Study IV draws on brotherhood – the metaphor seen as most positive – adding a call for ‘working in unity as volunteers’, i.e. a context matching the metaphoric use in anthems, contrasting it with a) a call to work ‘as citizens’ or b) a non-matching context (‘being devoted’). While it was assumed that such a fitting mobilisation context (i.e. ‘working together’) would be buttressed by a family metaphor, similar results emerged. In a sample (n = 102) matched to the overall population, the brother metaphor did not have an effect on national identification and participants reported lower agreement with a statement presented together with a family metaphor, often providing associations of nationalism or Nazism. The fifth study responded to the frequent associations of the Second World War by providing British (n = 109) and German (n = 113) students with a distant past (1830s) or WW II context prior to presenting a text that was either using family metaphors or not. It aimed to test whether avoiding a link to the Second World War would alleviate the negative associations. However, the results pointed in the opposite direction, i.e. German participants were more likely to invest in their nations if family metaphors and the 1930s occurred together, albeit the negative understanding of family metaphors provided in the previous studies remained, which can be interpreted as an expression of collective guilt. In the last study, a fictitious nation was presented to a general student sample at the University of St Andrews (n = 198) as either trying to achieve independence through militant struggle or building cultural institutions. As in the previous studies, the majority of participants saw family metaphors as negative, and only a small minority from countries with a higher acceptance of power-distance described them in a positive light. This thesis argues that, in the light of the results, the family metaphor has to be understood as evoking historically situated meanings and is seen as essentialising nationhood, a notion predominantly not matching the understanding participants had of their nation and consequently being rejected. It suggests that a) (national) identity research needs to be aware of context and b) other frameworks for exalted attachment should be investigated.
2013-06-25T00:00:00ZLauenstein, OliverThe central question of this thesis is: “How can people be mobilised to feel strongly attached to or invest into their nations?” Following a review of literature on the psychology of nationhood, a social identity approach towards national attachment is suggested. The possibility of the family metaphor (e.g. fatherland) as a rhetorical device anchoring the nation in filial qualities (e.g. belonging) is discussed. In the first study, establishing the general prevalence of family metaphors and aiming to test their use as a means of mobilisation, the content of language corpora, speeches, parliamentary debates and national anthems is analysed. The results demonstrate frequent use, especially in connection to mobilisation (e.g. in speeches). Study II tests whether merely linking a stimulus to a family metaphor will elicit a positive response and increase national identification. It does so by presenting a student sample (n = 149) with a neutral picture stimulus with different titles including family terms and family metaphors; no effects of any particular picture title on national identity emerged, but a considerable share of participants provided negative Nazi-related associations when primed with ‘fatherland’. Given the apparent relevance of meaning, the third study employed a word association task to provide a more in-depth account of German (n = 119) and British students’ (n =138) common associations for family metaphors, confirming that some participants associate them with a negative past (e.g. WW II) or negative politics (e.g. nationalism). In an attempt to avoid the impact of said negative associations, Study IV draws on brotherhood – the metaphor seen as most positive – adding a call for ‘working in unity as volunteers’, i.e. a context matching the metaphoric use in anthems, contrasting it with a) a call to work ‘as citizens’ or b) a non-matching context (‘being devoted’). While it was assumed that such a fitting mobilisation context (i.e. ‘working together’) would be buttressed by a family metaphor, similar results emerged. In a sample (n = 102) matched to the overall population, the brother metaphor did not have an effect on national identification and participants reported lower agreement with a statement presented together with a family metaphor, often providing associations of nationalism or Nazism. The fifth study responded to the frequent associations of the Second World War by providing British (n = 109) and German (n = 113) students with a distant past (1830s) or WW II context prior to presenting a text that was either using family metaphors or not. It aimed to test whether avoiding a link to the Second World War would alleviate the negative associations. However, the results pointed in the opposite direction, i.e. German participants were more likely to invest in their nations if family metaphors and the 1930s occurred together, albeit the negative understanding of family metaphors provided in the previous studies remained, which can be interpreted as an expression of collective guilt. In the last study, a fictitious nation was presented to a general student sample at the University of St Andrews (n = 198) as either trying to achieve independence through militant struggle or building cultural institutions. As in the previous studies, the majority of participants saw family metaphors as negative, and only a small minority from countries with a higher acceptance of power-distance described them in a positive light. This thesis argues that, in the light of the results, the family metaphor has to be understood as evoking historically situated meanings and is seen as essentialising nationhood, a notion predominantly not matching the understanding participants had of their nation and consequently being rejected. It suggests that a) (national) identity research needs to be aware of context and b) other frameworks for exalted attachment should be investigated.Factors influencing the motivational salience of facesHahn, Amanda C.https://hdl.handle.net/10023/36192021-02-26T03:01:35Z2013-01-01T00:00:00ZMy research utilizes a behavioral key-press task adapted from the classic bar-press technique employed in many rodent studies of reward to explore the incentive salience of beauty among humans. In Chapter 2, I replicate previous findings indicating that gender differences exist for the incentive salience of beauty. I extend past findings with regard to the incentive salience of
heterosexual beauty by investigating the role of additional aspects of facial appearance. Here, I find that apparent health holds incentive salience. This may serve an adaptive function by
driving motivation to seek out healthy potential mates while avoiding infectious individuals.
In Chapter 3, I explore gender differences in the incentive salience of adult and infant faces. I show that women demonstrate greater motivation, overall, to view infant faces while both men and women differentiate between the high-cute and low-cute versions of infant faces,
suggesting that infant cuteness may hold incentive salience for both men and women but that infants in general have higher incentive salience for women.
In Chapters 4 and 5, I investigate individual differences and variation across the menstrual cycle for women viewing adult faces. Women's own attractiveness was found to influence motivation to view attractive individuals, especially same-sex individuals. Within-subject variations in motivation across the menstrual cycle were apparent for the incentive salience of same-sex
beauty. Taken together, the results of these experiments suggest that the incentive salience of same-sex faces among women may be partially driven by intrasexual competition – a novel
explanation for women’s motivation to view same-sex individuals. Overall my research has indicated that infant cuteness, adult attractiveness and apparent health influence the
motivational value of faces, while individual differences also exist among women with respect to own attractiveness and fertility. The key-press paradigm offers an exciting new method for
exploring inter- and intra-sexual behavior in humans.
2013-01-01T00:00:00ZHahn, Amanda C.My research utilizes a behavioral key-press task adapted from the classic bar-press technique employed in many rodent studies of reward to explore the incentive salience of beauty among humans. In Chapter 2, I replicate previous findings indicating that gender differences exist for the incentive salience of beauty. I extend past findings with regard to the incentive salience of
heterosexual beauty by investigating the role of additional aspects of facial appearance. Here, I find that apparent health holds incentive salience. This may serve an adaptive function by
driving motivation to seek out healthy potential mates while avoiding infectious individuals.
In Chapter 3, I explore gender differences in the incentive salience of adult and infant faces. I show that women demonstrate greater motivation, overall, to view infant faces while both men and women differentiate between the high-cute and low-cute versions of infant faces,
suggesting that infant cuteness may hold incentive salience for both men and women but that infants in general have higher incentive salience for women.
In Chapters 4 and 5, I investigate individual differences and variation across the menstrual cycle for women viewing adult faces. Women's own attractiveness was found to influence motivation to view attractive individuals, especially same-sex individuals. Within-subject variations in motivation across the menstrual cycle were apparent for the incentive salience of same-sex
beauty. Taken together, the results of these experiments suggest that the incentive salience of same-sex faces among women may be partially driven by intrasexual competition – a novel
explanation for women’s motivation to view same-sex individuals. Overall my research has indicated that infant cuteness, adult attractiveness and apparent health influence the
motivational value of faces, while individual differences also exist among women with respect to own attractiveness and fertility. The key-press paradigm offers an exciting new method for
exploring inter- and intra-sexual behavior in humans.Context-dependent decision making in wild rufous hummingbirdsMorgan, Katehttps://hdl.handle.net/10023/36162019-04-01T10:40:10Z2013-01-01T00:00:00ZConventional models of decision making assume that animals and humans will evaluate
available options based on the benefit that they provide and then choose the option that
provides the largest benefit. However, there is evidence that the choices of both animals
and humans violate this assumption as the choices that are made can be altered by the
context in which decisions are presented. In this thesis I used free–living, foraging rufous hummingbirds (Selasphorus rufus) to investigate the effect of context on the decisions they make. Firstly, I gave birds choices between two preferred options and found that the addition of a third non-preferred option changed their preference when options varied in
either two dimensions simultaneously (volume and concentration of sucrose), or in only a
single dimension (volume or concentration). I also manipulated the learning context and
found that hummingbirds have stronger preferences when options are learned
simultaneously than when those same options are learned about sequentially. I also
manipulated the experience that birds had of the options prior to the choice and found that birds with prior experience did not make different choices than hummingbirds without prior experience. In addition to work with hummingbirds, I also completed experiments with humans looking at the effect of context on decisions about health of others. I manipulated the yellowness of faces and found that when participants choose between two preferred options the addition of non-preferred options changed their preference. These data demonstrate humans and hummingbirds make irrational choices as the decision making context can change the choices that they make. Current theories of decision making are insufficient to explain context-dependent choices made by hummingbirds.
2013-01-01T00:00:00ZMorgan, KateConventional models of decision making assume that animals and humans will evaluate
available options based on the benefit that they provide and then choose the option that
provides the largest benefit. However, there is evidence that the choices of both animals
and humans violate this assumption as the choices that are made can be altered by the
context in which decisions are presented. In this thesis I used free–living, foraging rufous hummingbirds (Selasphorus rufus) to investigate the effect of context on the decisions they make. Firstly, I gave birds choices between two preferred options and found that the addition of a third non-preferred option changed their preference when options varied in
either two dimensions simultaneously (volume and concentration of sucrose), or in only a
single dimension (volume or concentration). I also manipulated the learning context and
found that hummingbirds have stronger preferences when options are learned
simultaneously than when those same options are learned about sequentially. I also
manipulated the experience that birds had of the options prior to the choice and found that birds with prior experience did not make different choices than hummingbirds without prior experience. In addition to work with hummingbirds, I also completed experiments with humans looking at the effect of context on decisions about health of others. I manipulated the yellowness of faces and found that when participants choose between two preferred options the addition of non-preferred options changed their preference. These data demonstrate humans and hummingbirds make irrational choices as the decision making context can change the choices that they make. Current theories of decision making are insufficient to explain context-dependent choices made by hummingbirds.Investigating facial correlates of dominance and trustworthiness : their biological underpinnings and perceptual propertiesLefevre, Carmen Emiliahttps://hdl.handle.net/10023/36132019-04-01T10:41:32Z2013-01-01T00:00:00ZInformation conveyed by the face can be used in social encounters to make fast decisions
about another person. Recently, a new model of face perception has been postulated (Oosterhof & Todorov, 2009) suggesting that there are two basic judgements that underlie person evaluations from faces: dominance and trustworthiness. But on the basis of which cues are these judgements made, and do these cues have biological validity? In this thesis I investigate two putative facial cues to dominance and trustworthiness; namely, facial width-to-height ratio
(fWHR) and skin yellowness.
In men, fWHR has previously been linked to aggressive and dominant behaviour as well
as the perception of these traits. Here I show that a more positive dominance related trait (achievement striving) is also related to this metric, indicating a general association of fWHR to dominance rather than simple aggression. Furthermore, I explore the biological underpinnings of this metric by showing 1) that contrary to initial findings and predictions fWHR is not sexually
dimorphic, and 2) that fWHR is associated with testosterone, indicating a physiological link between appearance and behaviour. Additionally, I extend current work on fWHR by showing that it acts as a cue to dominance not only in humans but also in non-human primates.
The second part of the current thesis firstly identifies skin yellowness as a novel cue used in trustworthiness judgement. It shows that this putatively carotenoid induced cue to current health is not only employed in mate choice context but may also play an important role in other
social context and in judgements of who poses an adequate partner for social interactions.
Secondly, I show that skin yellowness is inversely related to testosterone levels in men, showing for the first time an association between this carotenoid induced signal and testosterone in humans thereby extending previous work in birds.
2013-01-01T00:00:00ZLefevre, Carmen EmiliaInformation conveyed by the face can be used in social encounters to make fast decisions
about another person. Recently, a new model of face perception has been postulated (Oosterhof & Todorov, 2009) suggesting that there are two basic judgements that underlie person evaluations from faces: dominance and trustworthiness. But on the basis of which cues are these judgements made, and do these cues have biological validity? In this thesis I investigate two putative facial cues to dominance and trustworthiness; namely, facial width-to-height ratio
(fWHR) and skin yellowness.
In men, fWHR has previously been linked to aggressive and dominant behaviour as well
as the perception of these traits. Here I show that a more positive dominance related trait (achievement striving) is also related to this metric, indicating a general association of fWHR to dominance rather than simple aggression. Furthermore, I explore the biological underpinnings of this metric by showing 1) that contrary to initial findings and predictions fWHR is not sexually
dimorphic, and 2) that fWHR is associated with testosterone, indicating a physiological link between appearance and behaviour. Additionally, I extend current work on fWHR by showing that it acts as a cue to dominance not only in humans but also in non-human primates.
The second part of the current thesis firstly identifies skin yellowness as a novel cue used in trustworthiness judgement. It shows that this putatively carotenoid induced cue to current health is not only employed in mate choice context but may also play an important role in other
social context and in judgements of who poses an adequate partner for social interactions.
Secondly, I show that skin yellowness is inversely related to testosterone levels in men, showing for the first time an association between this carotenoid induced signal and testosterone in humans thereby extending previous work in birds.Development of a neurophysiological sensory gating model in the rat to aid in the preclinical identification of possible treatments of sensory flooding in schizophreniaBloomfield, Andrewhttps://hdl.handle.net/10023/36042019-04-01T10:40:31Z2011-01-01T00:00:00ZObjective: It has been widely hypothesized that a failure to properly filter, or ‘gate’, incoming auditory information occurs in schizophrenic patients. This can be observed in a reduced event-related potential response to the second of a pair of clicks, and this is referred to as
P50 suppression after the name of the component that is attenuated to the second click. Our aim was to develop a model of gating failure in rats by measuring event-related potentials at different intervals between the clicks to validate that apparent gating in rats looks like P50 suppression in humans. We also sought to determine the relationship between two of the most commonly used assays of auditory gating: the mismatch negativity (an event-related potential evoked when a series of standard tones is followed by a deviant or oddball tone) and neurophysiological suppression in the double-click paradigm.
Methods: Male outbred Lister Hooded rats (N=8) were tested using electrophysiology
to record P50-like event-related potentials (ERPs) to assess the overall competence of the rats' sensory gating. The rat N40 potential, thought to be equivalent to the human P50 potential, was measured after each of two 85-dBZ paired (conditioning and test) 0.1msec duration clicks separated by inter-stimulus intervals of 250msec, 500msec, 1000msec, and 2000msec presented at 10second inter-trial intervals. If the N40 potentials are similar to the human P50, then the magnitude of the potential of the second click should be attenuated (a measure of gating of the repetitive stimulus). Additionally, we were interested in whether the suppression of the rat N40 to the second click was similar to the suppression of the human P50 in being vulnerable to disruption by amphetamine. We measured N40 suppression in four conditions: pre-drug, after saline injection, after 6 dextroamphetamine
injection, and post-drug. Finally, we correlated the N40suppression with another neurophysiological measure of gating, the mismatch negativity.
Results: We determined that as the inter-stimulus interval increased in duration, the degree of N40 suppression decreased linearly. The administration of d-amphetamine had a non-significant effect, although our results indicate that further testing with a slightly larger sample size would be relevant. Finally, the relationship between the MMN and N40 suppression was weak, which is similar to the relationship between the human P50 suppression and mismatch negativity.
Conclusions: These data are a relevant initial step towards a neurophysiological sensory gating model to aid in preclinical identification of possible treatments of sensory flooding in schizophrenia. The characteristics of the rat N40 suppression match those of the human P50 suppression with the apparent exception of vulnerability to disruption by amphetamine.
2011-01-01T00:00:00ZBloomfield, AndrewObjective: It has been widely hypothesized that a failure to properly filter, or ‘gate’, incoming auditory information occurs in schizophrenic patients. This can be observed in a reduced event-related potential response to the second of a pair of clicks, and this is referred to as
P50 suppression after the name of the component that is attenuated to the second click. Our aim was to develop a model of gating failure in rats by measuring event-related potentials at different intervals between the clicks to validate that apparent gating in rats looks like P50 suppression in humans. We also sought to determine the relationship between two of the most commonly used assays of auditory gating: the mismatch negativity (an event-related potential evoked when a series of standard tones is followed by a deviant or oddball tone) and neurophysiological suppression in the double-click paradigm.
Methods: Male outbred Lister Hooded rats (N=8) were tested using electrophysiology
to record P50-like event-related potentials (ERPs) to assess the overall competence of the rats' sensory gating. The rat N40 potential, thought to be equivalent to the human P50 potential, was measured after each of two 85-dBZ paired (conditioning and test) 0.1msec duration clicks separated by inter-stimulus intervals of 250msec, 500msec, 1000msec, and 2000msec presented at 10second inter-trial intervals. If the N40 potentials are similar to the human P50, then the magnitude of the potential of the second click should be attenuated (a measure of gating of the repetitive stimulus). Additionally, we were interested in whether the suppression of the rat N40 to the second click was similar to the suppression of the human P50 in being vulnerable to disruption by amphetamine. We measured N40 suppression in four conditions: pre-drug, after saline injection, after 6 dextroamphetamine
injection, and post-drug. Finally, we correlated the N40suppression with another neurophysiological measure of gating, the mismatch negativity.
Results: We determined that as the inter-stimulus interval increased in duration, the degree of N40 suppression decreased linearly. The administration of d-amphetamine had a non-significant effect, although our results indicate that further testing with a slightly larger sample size would be relevant. Finally, the relationship between the MMN and N40 suppression was weak, which is similar to the relationship between the human P50 suppression and mismatch negativity.
Conclusions: These data are a relevant initial step towards a neurophysiological sensory gating model to aid in preclinical identification of possible treatments of sensory flooding in schizophrenia. The characteristics of the rat N40 suppression match those of the human P50 suppression with the apparent exception of vulnerability to disruption by amphetamine.Some aspects of visual discomfortO'Hare, Louisehttps://hdl.handle.net/10023/35512019-04-01T10:42:01Z2013-06-25T00:00:00ZVisual discomfort is the adverse sensations, such as headaches and eyestrain,
encountered on viewing certain stimuli. These sensations can arise under certain
viewing conditions, such as stereoscopic viewing and prolonged reading
of text patterns. Also, discomfort can occur as a result of viewing stimuli
with certain spatial properties, including stripes and filtered noise patterns
of particular spatial frequency. This thesis is an exploration of the stimulus
properties causing discomfort, within the framework of two theoretical explanations.
Both of the explanations relate to the stimuli being difficult for the
visual system to process. The first is concerned with discomfort being the result
of inefficient neural processing. Neural activity requires energy to process
information, and stimuli that demand a lot of energy to be processed might be
uncomfortable. The second explanation revolves around uncomfortable stimuli
not being effective in driving the accommodative (focussing) response. Accommodation
relies on the stimulus as a cue to drive the response effectively - an
uninformative cue might result in discomfort from an uncertain accommodative
response. The following research investigates both these possibilities using a
combination of psychophysical experimentation, questionnaire-based surveys
on non-clinical populations, and computational modelling. The implications
of the work for clinical populations are also discussed.
2013-06-25T00:00:00ZO'Hare, LouiseVisual discomfort is the adverse sensations, such as headaches and eyestrain,
encountered on viewing certain stimuli. These sensations can arise under certain
viewing conditions, such as stereoscopic viewing and prolonged reading
of text patterns. Also, discomfort can occur as a result of viewing stimuli
with certain spatial properties, including stripes and filtered noise patterns
of particular spatial frequency. This thesis is an exploration of the stimulus
properties causing discomfort, within the framework of two theoretical explanations.
Both of the explanations relate to the stimuli being difficult for the
visual system to process. The first is concerned with discomfort being the result
of inefficient neural processing. Neural activity requires energy to process
information, and stimuli that demand a lot of energy to be processed might be
uncomfortable. The second explanation revolves around uncomfortable stimuli
not being effective in driving the accommodative (focussing) response. Accommodation
relies on the stimulus as a cue to drive the response effectively - an
uninformative cue might result in discomfort from an uncertain accommodative
response. The following research investigates both these possibilities using a
combination of psychophysical experimentation, questionnaire-based surveys
on non-clinical populations, and computational modelling. The implications
of the work for clinical populations are also discussed.The effects of conflict strength and ageing on cognitive controlStrozyk, Jessica Vanessahttps://hdl.handle.net/10023/35492020-04-01T02:02:52Z2013-06-01T00:00:00ZIn this thesis, I investigated effects of conflict strength and ageing on cognitive control. Conflict strength was manipulated in the Eriksen flanker task using two different approaches: 1. independent variation of flanker and target contrast; 2. manipulation of stimulus onset asynchrony (SOA). Reducing flanker contrast relative to target contrast decreased conflict strength, as shown by a reduction in compatibility effects, when contrast conditions were presented in a randomized fashion but not when they were presented block-wise. An SOA of 100 ms did lead to increased compatibility effects compared to SOAs of 0 ms and 200 ms. Effects of conflict appear to be reflected in the N2 component of the ERP. Although priming played a crucial role in the emergence of the sequential adjustment effect, conflict strength also influenced this effect to a certain degree, supporting the claim that sequential adjustments represent an adaptation of cognitive control. Post-error slowing and error-related ERP components, on the other hand, were not affected by the conflict manipulations, suggesting that errors cannot be explained in terms of conflict processing. Effects of ageing on cognitive control were investigated in a group of middle-aged participants. Although physiological indicators of conflict and error processing were compromised in this age group and overall response times were increased, compatibility, sequential adjustment, and post-error slowing effects were of comparable size as in young adults. These findings suggest that participants could successfully compensate for age-related physiological changes at this early stage of ageing. In conclusion, the research presented in this thesis provided important information to extend our knowledge of factors influencing cognitive control processes.
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2013-06-01T00:00:00ZStrozyk, Jessica VanessaIn this thesis, I investigated effects of conflict strength and ageing on cognitive control. Conflict strength was manipulated in the Eriksen flanker task using two different approaches: 1. independent variation of flanker and target contrast; 2. manipulation of stimulus onset asynchrony (SOA). Reducing flanker contrast relative to target contrast decreased conflict strength, as shown by a reduction in compatibility effects, when contrast conditions were presented in a randomized fashion but not when they were presented block-wise. An SOA of 100 ms did lead to increased compatibility effects compared to SOAs of 0 ms and 200 ms. Effects of conflict appear to be reflected in the N2 component of the ERP. Although priming played a crucial role in the emergence of the sequential adjustment effect, conflict strength also influenced this effect to a certain degree, supporting the claim that sequential adjustments represent an adaptation of cognitive control. Post-error slowing and error-related ERP components, on the other hand, were not affected by the conflict manipulations, suggesting that errors cannot be explained in terms of conflict processing. Effects of ageing on cognitive control were investigated in a group of middle-aged participants. Although physiological indicators of conflict and error processing were compromised in this age group and overall response times were increased, compatibility, sequential adjustment, and post-error slowing effects were of comparable size as in young adults. These findings suggest that participants could successfully compensate for age-related physiological changes at this early stage of ageing. In conclusion, the research presented in this thesis provided important information to extend our knowledge of factors influencing cognitive control processes.Face evaluation : perceptual and neurophysiological responses to pro-social attributionsDzhelyova, Milenahttps://hdl.handle.net/10023/35142019-04-01T10:41:34Z2013-06-25T00:00:00ZThe pro-sociality of humans is manifested by the existence of cooperation in levels not common with any other species. Previous studies suggest that snap judgements of individuals are enough to determine if someone is a potential partner for cooperation. In addition to the often studied facial characteristics affecting cooperativeness and trustworthiness attribution (kin resemblance; attractiveness and emotional expression), the experimental work reported here examined the influence of head posture; gaze direction and skin colour on the attribution of trustworthiness and cooperation. A slightly tilted head (less than 3° downward) increased the perception of cooperativeness, especially for male and hostile looking faces. The importance of head tilt increased with decreased self-assessed dominance. Furthermore, even though some evidence that the effect of head posture is independent of gaze direction was found, gaze direction was also a strong indicator of cooperative intentions. Direct gaze and gaze slightly looking down (3°) were perceived as more cooperative than deviations of gaze outside this range (3° up or 6°- 9° down). Skin colour, a putative cue to current health status, was also found to impact on trustworthiness perception with a healthy skin colour increasing trustworthiness ratings. Additionally, as cooperative and trust decisions are vital for survival and social interactions, decisions based on facial appearance are made quickly and automatically as demonstrated by a trustworthiness modulation on an early face related component with 170 ms of exposure. Collectively, these findings suggest that facial characteristics employed to infer trust and cooperativeness help the observer to assess the motives and intentions of the individuals and assist the choice of partners that will lead to increased benefits and reduced costs in collaborative actions. Such considerations fit well with the evolutionary theory of cooperation as reciprocated social exchange.
2013-06-25T00:00:00ZDzhelyova, MilenaThe pro-sociality of humans is manifested by the existence of cooperation in levels not common with any other species. Previous studies suggest that snap judgements of individuals are enough to determine if someone is a potential partner for cooperation. In addition to the often studied facial characteristics affecting cooperativeness and trustworthiness attribution (kin resemblance; attractiveness and emotional expression), the experimental work reported here examined the influence of head posture; gaze direction and skin colour on the attribution of trustworthiness and cooperation. A slightly tilted head (less than 3° downward) increased the perception of cooperativeness, especially for male and hostile looking faces. The importance of head tilt increased with decreased self-assessed dominance. Furthermore, even though some evidence that the effect of head posture is independent of gaze direction was found, gaze direction was also a strong indicator of cooperative intentions. Direct gaze and gaze slightly looking down (3°) were perceived as more cooperative than deviations of gaze outside this range (3° up or 6°- 9° down). Skin colour, a putative cue to current health status, was also found to impact on trustworthiness perception with a healthy skin colour increasing trustworthiness ratings. Additionally, as cooperative and trust decisions are vital for survival and social interactions, decisions based on facial appearance are made quickly and automatically as demonstrated by a trustworthiness modulation on an early face related component with 170 ms of exposure. Collectively, these findings suggest that facial characteristics employed to infer trust and cooperativeness help the observer to assess the motives and intentions of the individuals and assist the choice of partners that will lead to increased benefits and reduced costs in collaborative actions. Such considerations fit well with the evolutionary theory of cooperation as reciprocated social exchange.Cognitive and brain function in adults with Type 1 diabetes mellitus : is there evidence of accelerated ageing?Johnston, Harriet N.https://hdl.handle.net/10023/34462019-04-01T10:40:14Z2013-06-25T00:00:00ZThe physical complications of Type 1 diabetes mellitus (T1DM) have been understood as an accelerated ageing process (Morley, 2008). Do people with T1DM also experience accelerated cognitive and brain ageing? Using findings from research of the normal cognitive and brain ageing process and conceptualized in theories of the functional brain changes in cognitive ageing, a combination of cognitive testing and functional magnetic resonance imaging (fMRI) techniques were used to evaluate evidence of accelerated cognitive and brain ageing in middle-aged adults with T1DM.
The first part of this thesis comprises a cognitive study of 94 adults (≥ 45 years of age) with long duration (≥ 10 years) of T1DM. Participants completed cognitive assessment and questionnaires on general mood and feelings about living with diabetes. Findings highlighted the importance of microvascular disease (specifically retinopathy) as an independent predictor of cognitive function. The incidence and predictors of mild cognitive impairment (MCI) were then explored. Results indicate a higher percentage of the group met criteria for MCI than expected based on incidence rates in the general population, providing initial evidence of accelerated cognitive ageing. Psychological factors were explored next. The relationship between the measures of well-being, diabetes health, and cognitive function highlighted the need for attention to patient’s psychological well-being in diabetes care. Finally, a subgroup of 30 participants between the ages of 45 and 65 who differed on severity of retinopathy were selected to take part in an fMRI study. Blood oxygen level dependent (BOLD) activity was evaluated while participants were engaged in cognitive tasks and during rest. The findings provided evidence that the pattern of BOLD activation and functional connectivity for those with high severity of retinopathy are similar to patterns found in adults over the age of 65. In line with the theories of cognitive ageing, functional brain changes appear to maintain a level of cognitive function. Evidence of accelerated brain ageing in this primarily middle-aged group, emphasizes the importance of treatments and regimens to prevent or minimize microvascular complications.
2013-06-25T00:00:00ZJohnston, Harriet N.The physical complications of Type 1 diabetes mellitus (T1DM) have been understood as an accelerated ageing process (Morley, 2008). Do people with T1DM also experience accelerated cognitive and brain ageing? Using findings from research of the normal cognitive and brain ageing process and conceptualized in theories of the functional brain changes in cognitive ageing, a combination of cognitive testing and functional magnetic resonance imaging (fMRI) techniques were used to evaluate evidence of accelerated cognitive and brain ageing in middle-aged adults with T1DM.
The first part of this thesis comprises a cognitive study of 94 adults (≥ 45 years of age) with long duration (≥ 10 years) of T1DM. Participants completed cognitive assessment and questionnaires on general mood and feelings about living with diabetes. Findings highlighted the importance of microvascular disease (specifically retinopathy) as an independent predictor of cognitive function. The incidence and predictors of mild cognitive impairment (MCI) were then explored. Results indicate a higher percentage of the group met criteria for MCI than expected based on incidence rates in the general population, providing initial evidence of accelerated cognitive ageing. Psychological factors were explored next. The relationship between the measures of well-being, diabetes health, and cognitive function highlighted the need for attention to patient’s psychological well-being in diabetes care. Finally, a subgroup of 30 participants between the ages of 45 and 65 who differed on severity of retinopathy were selected to take part in an fMRI study. Blood oxygen level dependent (BOLD) activity was evaluated while participants were engaged in cognitive tasks and during rest. The findings provided evidence that the pattern of BOLD activation and functional connectivity for those with high severity of retinopathy are similar to patterns found in adults over the age of 65. In line with the theories of cognitive ageing, functional brain changes appear to maintain a level of cognitive function. Evidence of accelerated brain ageing in this primarily middle-aged group, emphasizes the importance of treatments and regimens to prevent or minimize microvascular complications.
Embodied metaphors and emotions in the moralization of restrained eating practicesSheikh, SanaBotindari, LuciaWhite, Emmahttps://hdl.handle.net/10023/33932023-04-18T09:45:34Z2013-05-01T00:00:00ZMoralization is the process whereby preferences are converted to values (Rozin, 1999). Two studies used an embodied metaphor approach, in which moral metaphors are grounded in one’s sense of physical cleanliness, to investigate whether restrained eating practices are moralized among women. Specifically, we predicted that the regulation of food intake by women is embodied in their feelings of physical cleanliness. Study 1 found that failures of restrained eating (i.e., overeating) increased accessibility of physical cleanliness-related words for women, but not men. Study 2 found that increased negative moral emotions fully mediated the effect of overeating on a desire for physical cleanliness. Overall, the studies argue for the importance of morality in restrained eating and in the central role of emotions in the embodiment of cognitive metaphors.
2013-05-01T00:00:00ZSheikh, SanaBotindari, LuciaWhite, EmmaMoralization is the process whereby preferences are converted to values (Rozin, 1999). Two studies used an embodied metaphor approach, in which moral metaphors are grounded in one’s sense of physical cleanliness, to investigate whether restrained eating practices are moralized among women. Specifically, we predicted that the regulation of food intake by women is embodied in their feelings of physical cleanliness. Study 1 found that failures of restrained eating (i.e., overeating) increased accessibility of physical cleanliness-related words for women, but not men. Study 2 found that increased negative moral emotions fully mediated the effect of overeating on a desire for physical cleanliness. Overall, the studies argue for the importance of morality in restrained eating and in the central role of emotions in the embodiment of cognitive metaphors.Reducing health inequalities in Scotland : the involvement of people with learning disabilities as national health service reviewersCampbell, MartinMartin, Mhttps://hdl.handle.net/10023/33802023-04-18T09:40:17Z2010-03-01T00:00:00ZReducing health inequalities is a key priority for the Scottish Government. Health authorities are expected to meet quality targets. The involvement of people with learning disabilities in health service review teams has been one of the initiatives used in by NHS Quality Improvement Scotland to empower patients and improve health services. This paper describes this initiative, how it was planned, and an evaluation by health staff, carers and people with learning disabilities. Recommendations are made to ensure the future success of this type of initiative in Scotland and elsewhere. This initiative was evaluated positively and tested traditional assumptions, challenging the power imbalance in patient-provider relationships. The theory and the practice of including people with learning disabilities as “expert patient” reviewers are discussed.
2010-03-01T00:00:00ZCampbell, MartinMartin, MReducing health inequalities is a key priority for the Scottish Government. Health authorities are expected to meet quality targets. The involvement of people with learning disabilities in health service review teams has been one of the initiatives used in by NHS Quality Improvement Scotland to empower patients and improve health services. This paper describes this initiative, how it was planned, and an evaluation by health staff, carers and people with learning disabilities. Recommendations are made to ensure the future success of this type of initiative in Scotland and elsewhere. This initiative was evaluated positively and tested traditional assumptions, challenging the power imbalance in patient-provider relationships. The theory and the practice of including people with learning disabilities as “expert patient” reviewers are discussed.Assessment of interpersonal risk (AIR) in adults with learning disabilities and challenging behaviour – piloting a new risk assessment toolCampbell, MartinMcCue, Michaelhttps://hdl.handle.net/10023/33792023-04-25T23:35:42Z2012-01-01T00:00:00ZA new risk assessment tool, Assessment of Interpersonal Risk (AIR), was piloted and evaluated to measure risk factors and compatibility between individuals living in an assessment and treatment unit in one NHS area. The adults with learning disabilities in this unit had severe and enduring mental health problems and/or behaviour that is severely challenging. The aims of this small-scale research project were to estimate the reciprocal risk to and from each individual across five main risk domains and to enhance professional judgement to make defensible decisions about interpersonal risk. Data were recorded on incidents involving five individuals over a period of 6 months. Individual Rating Profiles were incorporated into existing Individual Risk Management Plans, together with interpersonal profiles, recording risk evaluations between named individuals across the five risk domains. Results showed that the AIR tool may be a useful addition to existing effective risk management, to inform assessments and future discharge planning.
This article is a report on a research project funded by the Knowledge Transfer Partnership. This research was a joint project with NHS Fife. The accelerated long-stay Learning Disability Hospital closure programme in Scotland throughout the late 1990s and from 2000 onwards, resulted in the movement of residents both within and out-with these Hospitals to either community based housing models or to community based In-patient services. The legacy and impact of this residential service re-provision was that individuals experienced changes in those they lived with, and those who supported them. This process took place against the back-drop and dynamic of associated changes in environmental, procedural, situational and interpersonal risk. It was in recognition of the challenge that this change programme presented to care services in terms of defensible risk assessment and management that the Assessment of Interpersonal Risk tool was developed.
2012-01-01T00:00:00ZCampbell, MartinMcCue, MichaelA new risk assessment tool, Assessment of Interpersonal Risk (AIR), was piloted and evaluated to measure risk factors and compatibility between individuals living in an assessment and treatment unit in one NHS area. The adults with learning disabilities in this unit had severe and enduring mental health problems and/or behaviour that is severely challenging. The aims of this small-scale research project were to estimate the reciprocal risk to and from each individual across five main risk domains and to enhance professional judgement to make defensible decisions about interpersonal risk. Data were recorded on incidents involving five individuals over a period of 6 months. Individual Rating Profiles were incorporated into existing Individual Risk Management Plans, together with interpersonal profiles, recording risk evaluations between named individuals across the five risk domains. Results showed that the AIR tool may be a useful addition to existing effective risk management, to inform assessments and future discharge planning.A pilot project : evaluating community nurses' knowledge and understanding of the Adult Support and Protection (Scotland) Act 2007Campbell, MartinChamberlin, Dionnehttps://hdl.handle.net/10023/33782023-04-18T09:44:06Z2012-08-06T00:00:00ZPurpose: To evaluate understanding and knowledge of the Adult Support and Protection (Scotland) Act 2007 in a sample of community nurses working in learning disability services in Scotland. Design: Ten community nurses who worked in learning disability services in one NHS area were tested at two time points, four months apart using a questionnaire designed for this study by researchers and practitioners. Level of previous national training in the Adult Support and Protection Act, and length of time working with people with learning disabilities were recorded. Three domains of adult protection were included in the questionnaire: Principles of the Act and definitions; Adults at Risk of Harm; Protection, Assessment, Removal and Banning Orders. Findings: Questionnaire scores varied widely overall and across the three domains. There was no correlation between individual scores and training or length of work experience. The level of knowledge was below what might have been expected for this group, given the level of training and experience. Carefully designed verification of the impact of nationally approved Adult Support and Protection training is needed. Originality/Value: There is an absence of research in evaluating the impact of the approved Scottish Government training materials on staff knowledge and understanding of the 2007 Act, with staff attendance being taken as the main measure of training compliance. This was a small scale, pilot study and recommendations are made for the scope and methods of evaluation.
This research was funded from a grant from Queens Nursing Institute Scotland. Special Issue: Safeguarding adults at risk of harm in Scotland. Guest editor(s): Martin Campbell, James Hogg and Bridget Penhale.
2012-08-06T00:00:00ZCampbell, MartinChamberlin, DionnePurpose: To evaluate understanding and knowledge of the Adult Support and Protection (Scotland) Act 2007 in a sample of community nurses working in learning disability services in Scotland. Design: Ten community nurses who worked in learning disability services in one NHS area were tested at two time points, four months apart using a questionnaire designed for this study by researchers and practitioners. Level of previous national training in the Adult Support and Protection Act, and length of time working with people with learning disabilities were recorded. Three domains of adult protection were included in the questionnaire: Principles of the Act and definitions; Adults at Risk of Harm; Protection, Assessment, Removal and Banning Orders. Findings: Questionnaire scores varied widely overall and across the three domains. There was no correlation between individual scores and training or length of work experience. The level of knowledge was below what might have been expected for this group, given the level of training and experience. Carefully designed verification of the impact of nationally approved Adult Support and Protection training is needed. Originality/Value: There is an absence of research in evaluating the impact of the approved Scottish Government training materials on staff knowledge and understanding of the 2007 Act, with staff attendance being taken as the main measure of training compliance. This was a small scale, pilot study and recommendations are made for the scope and methods of evaluation.Dietary effects on skin colour : appearance-based incentives to improve fruit and vegetable consumptionWhitehead, Ross Davidhttps://hdl.handle.net/10023/33712019-07-01T10:04:31Z2013-06-25T00:00:00ZPoor diet precipitates significant social and economic burden, necessitating effective and economical dietary intervention strategies. Current population-level campaigns provide guidelines for living healthily and focus on the impact of lifestyle on chronic disease risk. Behavioural interventions which capitalise on individuals’ existing cognitions are likely to be more effective. A programme of work is presented here which evaluates the feasibility and efficacy of an appearance-based dietary intervention approach. This project aims to improve fruit and vegetable consumption by illustrating the associated benefits to skin appearance.
The impact of fruit and vegetable consumption on skin colour is assessed (Chapter 6), corroborating previous between-subjects evidence which finds that dermal yellowness (CIE b*) is positively associated with fruit and vegetable intake. This work also discovers that modest within-subject dietary change is sufficient to perceptibly alter skin colour within six weeks (Chapter 7). Perceptual preferences are examined (Chapters 5 to 9), finding that optimally healthy skin colouration is that associated with increased fruit and vegetable consumption.
Two behavioural intervention trials are conducted (Chapters 6 and 9) to evaluate whether visualising the impact of fruit and vegetable consumption on skin colour motivates dietary improvement. Relative to control groups, participants receiving an appearance-based intervention (in which the above effects are illustrated and explained) reported improvements in diet, particularly when illustrations were performed upon images of one’s own face. It may be valuable to disseminate such an intervention at a population level, though a number of further longitudinal studies are necessary to determine the wider effectiveness of this approach.
2013-06-25T00:00:00ZWhitehead, Ross DavidPoor diet precipitates significant social and economic burden, necessitating effective and economical dietary intervention strategies. Current population-level campaigns provide guidelines for living healthily and focus on the impact of lifestyle on chronic disease risk. Behavioural interventions which capitalise on individuals’ existing cognitions are likely to be more effective. A programme of work is presented here which evaluates the feasibility and efficacy of an appearance-based dietary intervention approach. This project aims to improve fruit and vegetable consumption by illustrating the associated benefits to skin appearance.
The impact of fruit and vegetable consumption on skin colour is assessed (Chapter 6), corroborating previous between-subjects evidence which finds that dermal yellowness (CIE b*) is positively associated with fruit and vegetable intake. This work also discovers that modest within-subject dietary change is sufficient to perceptibly alter skin colour within six weeks (Chapter 7). Perceptual preferences are examined (Chapters 5 to 9), finding that optimally healthy skin colouration is that associated with increased fruit and vegetable consumption.
Two behavioural intervention trials are conducted (Chapters 6 and 9) to evaluate whether visualising the impact of fruit and vegetable consumption on skin colour motivates dietary improvement. Relative to control groups, participants receiving an appearance-based intervention (in which the above effects are illustrated and explained) reported improvements in diet, particularly when illustrations were performed upon images of one’s own face. It may be valuable to disseminate such an intervention at a population level, though a number of further longitudinal studies are necessary to determine the wider effectiveness of this approach.Attention cues in apes and their role in social play behavior of western lowland gorillas (Gorilla gorilla gorilla)Mayhew, Jessica A.https://hdl.handle.net/10023/33682019-07-01T10:13:46Z2013-06-25T00:00:00ZThe research aims of this thesis are to investigate the attention cues available to and used by apes, especially gorillas (Gorilla gorilla), to ascertain the direction of conspecific attention during social interactions with a special reference to social play. Minimal research has been conducted on the role of attention cues - eye gaze, head, and body orientation - to regulate natural social interactions, such as social play, in non-human primates. This thesis begins with an investigation of the "cooperative eye hypothesis", which poses that humans have evolved a unique white sclera adaptation for advertising and detecting gaze direction. Chapter 2 reports the existence of a natural white sclera variation in a proportion of gorilla eyes - contradicting the widely held assumption that white sclera is an exclusively human characteristic - and analyzes the presence of white sclera in relation to other morphological changes in the human eye. The study concludes that the morphological elongation of the eye might be a more important and unique change than the white sclera coloration. Chapter 3 experimentally explores the contribution of white sclera in both great ape and human eye gaze to the perception of gaze direction detection by human observers. This chapter concludes that although white sclera contributes to the accuracy and speed of gaze direction detection (an assumption that this thesis has put to experimental test for the first time), this merely adds to the already efficient gaze cues available in the eye areas of the ape face. Chapter 4 investigates the role of eye gaze, head, and body orientations during gorilla social play behavior, and more specifically, introduces a novel analysis of "vigilance periods" (VPs), in which gorillas may use the interaction between attention cues to gauge the attention and intentions of play partners to successfully navigate play. The final study (Chapter 5) complements Chapter 4 and investigates the role of gorilla postures, behaviors, and movements during changes in attentional cue orientations. This chapter concludes that gorillas often engage in physical rest during VPs but maintain attentional engagement and can assemble and impart socially relevant information based on the behaviors, movements, and attention orientations of their partner. Together, these studies suggest that attention orientation is conveyed and assessed by gorillas through a variety of interacting cues to navigate and modify social play interactions.
2013-06-25T00:00:00ZMayhew, Jessica A.The research aims of this thesis are to investigate the attention cues available to and used by apes, especially gorillas (Gorilla gorilla), to ascertain the direction of conspecific attention during social interactions with a special reference to social play. Minimal research has been conducted on the role of attention cues - eye gaze, head, and body orientation - to regulate natural social interactions, such as social play, in non-human primates. This thesis begins with an investigation of the "cooperative eye hypothesis", which poses that humans have evolved a unique white sclera adaptation for advertising and detecting gaze direction. Chapter 2 reports the existence of a natural white sclera variation in a proportion of gorilla eyes - contradicting the widely held assumption that white sclera is an exclusively human characteristic - and analyzes the presence of white sclera in relation to other morphological changes in the human eye. The study concludes that the morphological elongation of the eye might be a more important and unique change than the white sclera coloration. Chapter 3 experimentally explores the contribution of white sclera in both great ape and human eye gaze to the perception of gaze direction detection by human observers. This chapter concludes that although white sclera contributes to the accuracy and speed of gaze direction detection (an assumption that this thesis has put to experimental test for the first time), this merely adds to the already efficient gaze cues available in the eye areas of the ape face. Chapter 4 investigates the role of eye gaze, head, and body orientations during gorilla social play behavior, and more specifically, introduces a novel analysis of "vigilance periods" (VPs), in which gorillas may use the interaction between attention cues to gauge the attention and intentions of play partners to successfully navigate play. The final study (Chapter 5) complements Chapter 4 and investigates the role of gorilla postures, behaviors, and movements during changes in attentional cue orientations. This chapter concludes that gorillas often engage in physical rest during VPs but maintain attentional engagement and can assemble and impart socially relevant information based on the behaviors, movements, and attention orientations of their partner. Together, these studies suggest that attention orientation is conveyed and assessed by gorillas through a variety of interacting cues to navigate and modify social play interactions.Forms of flexibility : associations between executive functions in the ratChase, E. Alexanderhttps://hdl.handle.net/10023/33652019-07-01T10:15:49Z2013-06-25T00:00:00ZExecutive control is a vital cognitive function that facilitates the focussing and shifting of attention, planning and working towards a goal, ignoring distractions, and flexibly responding to novel situations. Disruptions to executive control are seen in many psychiatric and neurodegenerative disorders, as well as healthy ageing, which can be profoundly detrimental. Despite having many effective and well-validated methodologies for detecting and quantifying these deficits, there are very few treatments — pharmacological or otherwise — for ameliorating executive dysfunction. This lack of progress can partly be blamed on difficulties associated with identifying drugs that enhance cognition in preclinical research. The work in this thesis aimed to expand our understanding of executive dysfunction — as well as the tasks that measure it — in rats. In results presented in chapter three, middle-aged rats demonstrated impaired reversal learning on the standard attentional set-shifting task, but this was treatable with a novel drug targeting the N-methyl-D-aspartate receptor. The age impairments seen in this experiment were similar to those previously found in young rats with orbital prefrontal cortex (OFC) lesions. The results of chapter four expanded on this similarity to show that, along with reversal deficits, young OFC-lesioned rats are impaired at forming attentional sets when tested on a modified task. In chapter five, another modified set-shifting task revealed that middle-aged rats also suffer from impaired set-formation, but their reversal learning impairments only manifest before attentional set has been formed — not after. Finally, in chapter six, the putative cognitive enhancer modafinil was found to exacerbate middle-aged rats’ reversal learning deficit, but it also enhanced their subsequent ability to form attentional set. These experiments reveal that modifying the rat attentional set-shifting task can sometimes make it a more effective tool for testing cognitive enhancers in preclinical settings.
2013-06-25T00:00:00ZChase, E. AlexanderExecutive control is a vital cognitive function that facilitates the focussing and shifting of attention, planning and working towards a goal, ignoring distractions, and flexibly responding to novel situations. Disruptions to executive control are seen in many psychiatric and neurodegenerative disorders, as well as healthy ageing, which can be profoundly detrimental. Despite having many effective and well-validated methodologies for detecting and quantifying these deficits, there are very few treatments — pharmacological or otherwise — for ameliorating executive dysfunction. This lack of progress can partly be blamed on difficulties associated with identifying drugs that enhance cognition in preclinical research. The work in this thesis aimed to expand our understanding of executive dysfunction — as well as the tasks that measure it — in rats. In results presented in chapter three, middle-aged rats demonstrated impaired reversal learning on the standard attentional set-shifting task, but this was treatable with a novel drug targeting the N-methyl-D-aspartate receptor. The age impairments seen in this experiment were similar to those previously found in young rats with orbital prefrontal cortex (OFC) lesions. The results of chapter four expanded on this similarity to show that, along with reversal deficits, young OFC-lesioned rats are impaired at forming attentional sets when tested on a modified task. In chapter five, another modified set-shifting task revealed that middle-aged rats also suffer from impaired set-formation, but their reversal learning impairments only manifest before attentional set has been formed — not after. Finally, in chapter six, the putative cognitive enhancer modafinil was found to exacerbate middle-aged rats’ reversal learning deficit, but it also enhanced their subsequent ability to form attentional set. These experiments reveal that modifying the rat attentional set-shifting task can sometimes make it a more effective tool for testing cognitive enhancers in preclinical settings.Multiple expressions of hemispheric asymmetry in captive chimpanzeesBraccini, Stephaniehttps://hdl.handle.net/10023/32272019-04-01T10:40:40Z2012-11-30T00:00:00ZThe degree to which non-human primate behaviour is lateralized, at individual or
population levels, remains controversial and over the last century, the issue of brain
lateralization in primates has been extensively researched and debated, yet no previous study has reported eye preference or head turning in great apes. This thesis examines three different expressions of hemispheric asymmetry in lateralized behaviours: hand preference for bipedal tool use, eye preference, and auditory laterality.
It is reported that bipedalism induced the subjects to become more lateralized, but not in any particular direction. Instead, it appeared that subtle pre-existing lateral biases, to the right or left, were emphasized with increasing postural demands.
Eye preference was assessed when animals looked through a hole, using one eye, at an
empty box, a mirror, a picture of a dog, a rubber snake, food biscuits, bananas, a rubber duck and a video camera. Main effects of stimulus type were reported for direction of eye preference, number of looks, and looking duration, but not for strength of eye
preference. A left-eye bias was found for viewing the rubber snake and a right eye bias
was found for viewing the bananas. In addition, a significant shift in eye preference took place from the initial look to subsequent looks when viewing the snake. The results reported are not consistent with the literature for other primate studies.
Lastly, auditory laterality was assessed using the Hauser and Andersson (1994) head
turning paradigm. Chimpanzee and American crow calls were broadcast to subjects
from 180° behind them and directional head turning was recorded. No difference in
turning direction or latency was found. This lack of result was attributed to the
methodology and underlying assumption that head turning is directly related to
hemispheric asymmetries and not influenced by any other processes.
2012-11-30T00:00:00ZBraccini, StephanieThe degree to which non-human primate behaviour is lateralized, at individual or
population levels, remains controversial and over the last century, the issue of brain
lateralization in primates has been extensively researched and debated, yet no previous study has reported eye preference or head turning in great apes. This thesis examines three different expressions of hemispheric asymmetry in lateralized behaviours: hand preference for bipedal tool use, eye preference, and auditory laterality.
It is reported that bipedalism induced the subjects to become more lateralized, but not in any particular direction. Instead, it appeared that subtle pre-existing lateral biases, to the right or left, were emphasized with increasing postural demands.
Eye preference was assessed when animals looked through a hole, using one eye, at an
empty box, a mirror, a picture of a dog, a rubber snake, food biscuits, bananas, a rubber duck and a video camera. Main effects of stimulus type were reported for direction of eye preference, number of looks, and looking duration, but not for strength of eye
preference. A left-eye bias was found for viewing the rubber snake and a right eye bias
was found for viewing the bananas. In addition, a significant shift in eye preference took place from the initial look to subsequent looks when viewing the snake. The results reported are not consistent with the literature for other primate studies.
Lastly, auditory laterality was assessed using the Hauser and Andersson (1994) head
turning paradigm. Chimpanzee and American crow calls were broadcast to subjects
from 180° behind them and directional head turning was recorded. No difference in
turning direction or latency was found. This lack of result was attributed to the
methodology and underlying assumption that head turning is directly related to
hemispheric asymmetries and not influenced by any other processes.The effect of female reproductive hormones on the perception of cutenessLewis, Jenniferhttps://hdl.handle.net/10023/32232019-04-01T10:41:05Z2012-11-30T00:00:00ZThe findings of two recent studies suggest that cuteness sensitivity may be modulated by the female reproductive hormones estrogen and progesterone, with women showing greater sensitivity than men (Sprengelmeyer et al 2009; Lobmaier et al 2010) and women using hormonal contraceptives showing a greater
sensitivity than naturally cycling women. Post-menopausal women were found to perform at the same level as men (Sprengelmeyer et al 2009). The present study aimed to extend these findings by determining if an equivalent pattern of differences occurs in the motivation to view pictures of infant faces. To investigate this question, men, naturally cycling women and women using oral contraceptives completed a key-press task in which they were able to increase or decrease the amount of time they spent viewing infant faces that varied in gender, expression and age. Following this, they rated the same set of faces for cuteness. Because levels of estrogen and progesterone fluctuate over the course of the menstrual cycle and over a month of oral contraceptive use, naturally cycling women and women using oral contraceptives completed the experiment at different times of their menstrual cycle or oral contraceptive regimen to determine the effects of cycle phase (menstrual, late follicular, luteal) and pill stage (pill phase, pill-break) on the level of key-pressing. Three key findings were made. First, there is no gender difference in the cuteness judgments of infant faces suggesting that cuteness is a universal construct, perceived in the same way by all. Second, there is a strong correlation between cuteness rating and viewing time, providing evidence that the incentive value of an infant face is modulated by cuteness. And third, there is no evidence that the incentive value of cuteness is
hormonally modulated. Regardless of gender, pill phase or cycle phase, the participants showed no difference in their motivation to view the infant faces. From these findings it appears that whilst sensitivity to cuteness in infant faces may be modulated by estrogen and progesterone, the motivation to view cute infant faces is not. It was concluded that these different components of cuteness processing evolved separately for different purposes associated with infant care.
2012-11-30T00:00:00ZLewis, JenniferThe findings of two recent studies suggest that cuteness sensitivity may be modulated by the female reproductive hormones estrogen and progesterone, with women showing greater sensitivity than men (Sprengelmeyer et al 2009; Lobmaier et al 2010) and women using hormonal contraceptives showing a greater
sensitivity than naturally cycling women. Post-menopausal women were found to perform at the same level as men (Sprengelmeyer et al 2009). The present study aimed to extend these findings by determining if an equivalent pattern of differences occurs in the motivation to view pictures of infant faces. To investigate this question, men, naturally cycling women and women using oral contraceptives completed a key-press task in which they were able to increase or decrease the amount of time they spent viewing infant faces that varied in gender, expression and age. Following this, they rated the same set of faces for cuteness. Because levels of estrogen and progesterone fluctuate over the course of the menstrual cycle and over a month of oral contraceptive use, naturally cycling women and women using oral contraceptives completed the experiment at different times of their menstrual cycle or oral contraceptive regimen to determine the effects of cycle phase (menstrual, late follicular, luteal) and pill stage (pill phase, pill-break) on the level of key-pressing. Three key findings were made. First, there is no gender difference in the cuteness judgments of infant faces suggesting that cuteness is a universal construct, perceived in the same way by all. Second, there is a strong correlation between cuteness rating and viewing time, providing evidence that the incentive value of an infant face is modulated by cuteness. And third, there is no evidence that the incentive value of cuteness is
hormonally modulated. Regardless of gender, pill phase or cycle phase, the participants showed no difference in their motivation to view the infant faces. From these findings it appears that whilst sensitivity to cuteness in infant faces may be modulated by estrogen and progesterone, the motivation to view cute infant faces is not. It was concluded that these different components of cuteness processing evolved separately for different purposes associated with infant care.ERP correlates of forgetting: an investigation of resource allocation as a potential neural mechanism behind retrieval-induced forgettingWalters, Mariehttps://hdl.handle.net/10023/32092019-04-01T10:42:05Z2012-06-19T00:00:00ZThe present study was aimed at investigating a potential mechanism behind
retrieval-induced forgetting that we have termed resource allocation. Three
experiments were designed around the notion that increasing the number memories
associated with one concept may reduce retrieval-induced forgetting by spreading out
the limited resources available for that concept. In two experiments, we expanded the
standard retrieval-induced forgetting (RIF) paradigm by increasing the number of
items in each category and varying the amount of Rp+ and Rp- items. In one of these
experiments, we recorded event-related potentials (ERPs) to examine the
electrophysiological correlates of retrieval-induced forgetting. We then compared
these findings to a standard version of the RIF paradigm as a control experiment. All
three experiments produced significant facilitation effects, but failed to produce
retrieval-induced forgetting. The absence of RIF in the present study, however, when
combined with the imaging data allows us to discern the ERP correlates of selective
retrieval from those of retrieval-induced forgetting. In the discussion, we present our
case against conclusions drawn in other studies about the ERP correlates of RIF, and
suggest that the characteristic frontoparietal components often found in RIF studies
reflect the neural correlates of selective retrieval rather than inhibition.
2012-06-19T00:00:00ZWalters, MarieThe present study was aimed at investigating a potential mechanism behind
retrieval-induced forgetting that we have termed resource allocation. Three
experiments were designed around the notion that increasing the number memories
associated with one concept may reduce retrieval-induced forgetting by spreading out
the limited resources available for that concept. In two experiments, we expanded the
standard retrieval-induced forgetting (RIF) paradigm by increasing the number of
items in each category and varying the amount of Rp+ and Rp- items. In one of these
experiments, we recorded event-related potentials (ERPs) to examine the
electrophysiological correlates of retrieval-induced forgetting. We then compared
these findings to a standard version of the RIF paradigm as a control experiment. All
three experiments produced significant facilitation effects, but failed to produce
retrieval-induced forgetting. The absence of RIF in the present study, however, when
combined with the imaging data allows us to discern the ERP correlates of selective
retrieval from those of retrieval-induced forgetting. In the discussion, we present our
case against conclusions drawn in other studies about the ERP correlates of RIF, and
suggest that the characteristic frontoparietal components often found in RIF studies
reflect the neural correlates of selective retrieval rather than inhibition.Linking actions to outcomes : the role of the posterior pedunculopontine tegmental nucleus in instrumental learningMacLaren, Duncan A. A.https://hdl.handle.net/10023/31832020-03-03T10:32:24Z2012-11-01T00:00:00ZLocated in the mesopontine tegmentum, the pedunculopontine tegmental nucleus (PPTg) is comprised principally of glutamatergic, cholinergic and GABAergic neurons. In addition to being fully integrated into basal ganglia, PPTg projects to thalamus and motor output sites in the brainstem. Previous studies have shown a range of behavioural changes after PPTg manipulation. Prominent amongst these is an apparent deficit in the ability to learn the consequences of actions. PPTg is divisible into a posterior component (pPPTg) in receipt of rapid polymodal sensory input and projecting into VTA/SNc dopamine neurons and an anterior component (aPPTg) in receipt of basal ganglia outflow and projecting into SNc and lower brainstem structures. The research described here assesses the role of the pPPTg in instrumental learning. Using a contingency degradation paradigm, it was shown that inactivation of the pPPTg (by muscimol microinfusion) specifically blocked the updating of associations between actions and outcomes, without the affecting the ability to re-execute previously learned instrumental actions. Selective bilateral destruction of pPPTg cholinergic neurons (with the fusion toxin diphtheria toxin – urotensin II [Dtx-UII]) resulted in >90% loss of pPPTg cholinergic neurons. These lesions produced no detectable changes on any measured aspect of an instrumental learning task consisting of various fixed and variable ratio schedules of reinforcement and extinction. Subsequent experiments found that the same selective cholinergic pPPTg lesions also produced no changes in the locomotor response to nicotine or rate of nicotine sensitisation. These results are the first to demonstrate a brainstem role in action-outcome learning. Results support the view that PPTg performs a ‘first pass’ analysis on incoming sensory data and interfaces salient aspects of this with appropriate basal ganglia and brainstem circuitry, with glutamatergic pPPTg projections sending an essential signal and cholinergic projections performing as part of a wider modulatory system.
2012-11-01T00:00:00ZMacLaren, Duncan A. A.Located in the mesopontine tegmentum, the pedunculopontine tegmental nucleus (PPTg) is comprised principally of glutamatergic, cholinergic and GABAergic neurons. In addition to being fully integrated into basal ganglia, PPTg projects to thalamus and motor output sites in the brainstem. Previous studies have shown a range of behavioural changes after PPTg manipulation. Prominent amongst these is an apparent deficit in the ability to learn the consequences of actions. PPTg is divisible into a posterior component (pPPTg) in receipt of rapid polymodal sensory input and projecting into VTA/SNc dopamine neurons and an anterior component (aPPTg) in receipt of basal ganglia outflow and projecting into SNc and lower brainstem structures. The research described here assesses the role of the pPPTg in instrumental learning. Using a contingency degradation paradigm, it was shown that inactivation of the pPPTg (by muscimol microinfusion) specifically blocked the updating of associations between actions and outcomes, without the affecting the ability to re-execute previously learned instrumental actions. Selective bilateral destruction of pPPTg cholinergic neurons (with the fusion toxin diphtheria toxin – urotensin II [Dtx-UII]) resulted in >90% loss of pPPTg cholinergic neurons. These lesions produced no detectable changes on any measured aspect of an instrumental learning task consisting of various fixed and variable ratio schedules of reinforcement and extinction. Subsequent experiments found that the same selective cholinergic pPPTg lesions also produced no changes in the locomotor response to nicotine or rate of nicotine sensitisation. These results are the first to demonstrate a brainstem role in action-outcome learning. Results support the view that PPTg performs a ‘first pass’ analysis on incoming sensory data and interfaces salient aspects of this with appropriate basal ganglia and brainstem circuitry, with glutamatergic pPPTg projections sending an essential signal and cholinergic projections performing as part of a wider modulatory system.Sex differences in anxiety during adolescence : evidence from rodents and humansLynn, Debra Alanahttps://hdl.handle.net/10023/31522019-04-01T10:41:37Z2012-11-30T00:00:00ZAnxiety disorders commonly emerge during adolescence, and girls are diagnosed with these disorders more frequently than boys. Understanding why anxiety disorders emerge and why non-clinical anxiety symptoms increase during adolescence is important for understanding this sex difference and how to treat adolescent sufferers. Potential mechanisms, such as puberty or cognitive biases, can be investigated both in humans and in rodent models of anxiety. This thesis aimed to characterise sex differences and changes in anxiety-like behaviour across adolescence and into adulthood in the rat, and to examine anxiety and interpretive bias in adolescent humans. In rats, we examined performance on common tests of anxiety-like behaviour: the emergence test, open field and elevated plus-maze. Exploration on these tests increased from mid-adolescence into adulthood, and greater exploration by females was apparent from late adolescence. While the behaviours themselves remain interesting, caution on interpreting these behaviours as anxiety-related warranted and is discussed throughout the thesis. Potential effects of the ovarian cycle and testing order on EPM performance were also examined. In humans, 12-14 year old adolescents complete visual and written interpretive bias tasks, this bias being considered to be a cognitive vulnerability for anxiety. The results showed that, when imagining themselves in ambiguous scenarios, girls were more negative in their interpretations than boys. Additionally, both sexes also interpreted social scenarios more negatively than non-social scenarios. As puberty is thought to be important to the emergence of disorder during adolescence, interpretive bias could potentially mediate the puberty-anxiety relationship. While more interpretive bias work is needed in both species, the recent development of interpretive bias tasks for rodents provides an opportunity to move away from difficult to interpret tests of anxiety-like behaviour in rodents, and should allow for greater convergence of the human and rodent anxiety research.
Electronic version does not contain associated previously published material
2012-11-30T00:00:00ZLynn, Debra AlanaAnxiety disorders commonly emerge during adolescence, and girls are diagnosed with these disorders more frequently than boys. Understanding why anxiety disorders emerge and why non-clinical anxiety symptoms increase during adolescence is important for understanding this sex difference and how to treat adolescent sufferers. Potential mechanisms, such as puberty or cognitive biases, can be investigated both in humans and in rodent models of anxiety. This thesis aimed to characterise sex differences and changes in anxiety-like behaviour across adolescence and into adulthood in the rat, and to examine anxiety and interpretive bias in adolescent humans. In rats, we examined performance on common tests of anxiety-like behaviour: the emergence test, open field and elevated plus-maze. Exploration on these tests increased from mid-adolescence into adulthood, and greater exploration by females was apparent from late adolescence. While the behaviours themselves remain interesting, caution on interpreting these behaviours as anxiety-related warranted and is discussed throughout the thesis. Potential effects of the ovarian cycle and testing order on EPM performance were also examined. In humans, 12-14 year old adolescents complete visual and written interpretive bias tasks, this bias being considered to be a cognitive vulnerability for anxiety. The results showed that, when imagining themselves in ambiguous scenarios, girls were more negative in their interpretations than boys. Additionally, both sexes also interpreted social scenarios more negatively than non-social scenarios. As puberty is thought to be important to the emergence of disorder during adolescence, interpretive bias could potentially mediate the puberty-anxiety relationship. While more interpretive bias work is needed in both species, the recent development of interpretive bias tasks for rodents provides an opportunity to move away from difficult to interpret tests of anxiety-like behaviour in rodents, and should allow for greater convergence of the human and rodent anxiety research.Form and function of non-linguistic calls in human infantsKersken, Verenahttps://hdl.handle.net/10023/31492019-07-01T10:16:21Z2012-06-19T00:00:00ZBefore infants speak their first word, they already produce a large variety of sounds. Whilst the developmental process that leads to speech production is very well documented, little attention is given to how non-linguistic sounds function in the child’s everyday environment and whether they show acoustic consistencies similar to those found in the calls of non-human primates. This thesis investigated whether human infants between 11 and 18 months have “calls”. The first study observed 22 infants in their everyday nursery environment in Scotland and identified a number of contexts in which infants produced vocal behaviour. Vocalisations in five of these contexts, giving, declarative pointing, food requests, protests and action requests, were then subjected to an acoustic analysis. Results of the discriminant analysis suggest that four categories of vocal behaviour can be distinguished on the basis of their acoustic properties alone. To investigate whether these calls are part of a universal human repertoire, we conducted a cross-cultural comparison of the acoustic properties of vocal behaviour showed that, despite a slightly higher level of variation; four categories of calls could still be discriminated above chance level. This suggests that human infants possess calls with rather fixed acoustic properties as part of their vocal repertoire in addition to other, more flexible vocal behaviours. In order to assess whether listeners can gain information from these calls, we conducted a playback study with parents, experienced and inexperienced participants. Results show that all participants can categorise all vocalisations above chance level. Parents were the only participants that showed significantly better scores in correctly classifying vocalisations recorded in Scotland over those recorded in Uganda. Overall, the studies demonstrated that infants, as part of their vocal repertoire, produce some classes of calls that have constant acoustic properties across infants from different cultures, and contain information about the infant’s activities that can be picked up by a listener.
2012-06-19T00:00:00ZKersken, VerenaBefore infants speak their first word, they already produce a large variety of sounds. Whilst the developmental process that leads to speech production is very well documented, little attention is given to how non-linguistic sounds function in the child’s everyday environment and whether they show acoustic consistencies similar to those found in the calls of non-human primates. This thesis investigated whether human infants between 11 and 18 months have “calls”. The first study observed 22 infants in their everyday nursery environment in Scotland and identified a number of contexts in which infants produced vocal behaviour. Vocalisations in five of these contexts, giving, declarative pointing, food requests, protests and action requests, were then subjected to an acoustic analysis. Results of the discriminant analysis suggest that four categories of vocal behaviour can be distinguished on the basis of their acoustic properties alone. To investigate whether these calls are part of a universal human repertoire, we conducted a cross-cultural comparison of the acoustic properties of vocal behaviour showed that, despite a slightly higher level of variation; four categories of calls could still be discriminated above chance level. This suggests that human infants possess calls with rather fixed acoustic properties as part of their vocal repertoire in addition to other, more flexible vocal behaviours. In order to assess whether listeners can gain information from these calls, we conducted a playback study with parents, experienced and inexperienced participants. Results show that all participants can categorise all vocalisations above chance level. Parents were the only participants that showed significantly better scores in correctly classifying vocalisations recorded in Scotland over those recorded in Uganda. Overall, the studies demonstrated that infants, as part of their vocal repertoire, produce some classes of calls that have constant acoustic properties across infants from different cultures, and contain information about the infant’s activities that can be picked up by a listener.The effect of weight on health and face perception : a cross-cultural perspectiveCoetzee, Vinethttps://hdl.handle.net/10023/31312019-04-01T10:41:58Z2011-01-01T00:00:00ZMy research identifies facial adiposity, a measure of weight in the face, as a novel
facial cue to attractiveness and health. Previously identified facial cues, such as
symmetry, averageness, sexual dimorphism and skin condition, are not consistently
related to indices of actual health. In chapter 2 I demonstrate that facial adiposity is reliably
associated with judgements of facial attractiveness and health in Caucasians and also
with frequency and duration of respiratory infections, antibiotics use and blood pressure,
indicating that facial adiposity is a valid cue to health. Additionally, in chapter 3 I identify
three quantifiable facial shape cues that are reliably related to Body Mass Index (BMI)
and are used by observers to judge weight in Caucasian and African faces.
In chapter 4 I show that Western Caucasian women, but not men, prefer a
significantly lower facial adiposity when judging attractiveness than when judging health
in other women’s faces. This difference may reflect the influence of the media, since it
was only significant in women’s judgements and previous work showed that women
internalize media messages about body ideals more than men do. In contrast, African
participants in chapter 6 did not show any difference between the optimal facial adiposity
for health and attractiveness, which is consistent with the prediction that people living in
an environment with a high disease burden will base their concept of attractiveness more
closely on cues to health. Importantly, these different patterns of results for Western
Caucasian and African participants are unlikely to be due to cultural differences in media
ideals of beauty, since the new African body ideal portrayed by the South African media
is closely aligned with the Western ideal (chapter 5). Thus, my research suggests that
perceptions of facial adiposity may well be influenced by an interaction between
environmental factors and media ideals.
2011-01-01T00:00:00ZCoetzee, VinetMy research identifies facial adiposity, a measure of weight in the face, as a novel
facial cue to attractiveness and health. Previously identified facial cues, such as
symmetry, averageness, sexual dimorphism and skin condition, are not consistently
related to indices of actual health. In chapter 2 I demonstrate that facial adiposity is reliably
associated with judgements of facial attractiveness and health in Caucasians and also
with frequency and duration of respiratory infections, antibiotics use and blood pressure,
indicating that facial adiposity is a valid cue to health. Additionally, in chapter 3 I identify
three quantifiable facial shape cues that are reliably related to Body Mass Index (BMI)
and are used by observers to judge weight in Caucasian and African faces.
In chapter 4 I show that Western Caucasian women, but not men, prefer a
significantly lower facial adiposity when judging attractiveness than when judging health
in other women’s faces. This difference may reflect the influence of the media, since it
was only significant in women’s judgements and previous work showed that women
internalize media messages about body ideals more than men do. In contrast, African
participants in chapter 6 did not show any difference between the optimal facial adiposity
for health and attractiveness, which is consistent with the prediction that people living in
an environment with a high disease burden will base their concept of attractiveness more
closely on cues to health. Importantly, these different patterns of results for Western
Caucasian and African participants are unlikely to be due to cultural differences in media
ideals of beauty, since the new African body ideal portrayed by the South African media
is closely aligned with the Western ideal (chapter 5). Thus, my research suggests that
perceptions of facial adiposity may well be influenced by an interaction between
environmental factors and media ideals.Social learning from video demonstrations in chimpanzees (Pan troglodytes), children (Homo sapiens), and ravens (Corvus corax)Price, Elizabeth E.https://hdl.handle.net/10023/31212019-04-01T10:40:52Z2011-01-01T00:00:00ZThe capacity for cumulatively complex and constructive technologies is a
hallmark of human cognitive ability. Many species use tools, yet the breadth,
adaptability, and inventiveness of human tool use distinguishes us. Such complex
technological adaptations require the causal understanding to invent and perfect new
techniques and the ability to copy perceived behaviours. This has led to considerable
research comparing the social learning abilities of chimpanzees and young children on
tool-using tasks, yet experimental studies directly investigating tool modification are rare.
The studies outlined in this thesis sought to assess the social learning abilities of
chimpanzees and children by manipulating both the complexity of a tool modification
method and the amount of information available in a demonstration. Video
demonstrations of conspecifics were used in lieu of live models, in order to manipulate
the quality and quantity of information directly. Both chimpanzees and children presented
with complete information about the modification process learned to combine two tools
together to make a more efficient tool significantly more than those provided with less
information. Unlike chimpanzees, children presented with a more perceptually opaque
method of tool modification (twisting and extending an internal rod) were also able to
socially learn the task, despite the fact that none of the children in the control condition
successfully solved the task. Both children and chimpanzees who solved the task after
seeing a demonstration also persisted in using the socially learned method two-weeks
later, even when it was no longer necessary. These results identify potent social learning
effects in both chimpanzees and children, however, children proved superior to
chimpanzees in observationally learning finer manipulative techniques.
This thesis also provides the first analysis of video stimuli in ravens. To assess the
feasibility of the methodology, ravens were first presented with different types of video
stimuli, varying in terms of the subject identity. Ravens showed a preference for video
footage of other ravens over different species of birds. In a second study, ravens who saw
a conspecific solve a two-step task were more likely to attempt a solution than those who
had not. This represents the first evidence of social learning from a video demonstration
in ravens and further supports the use of this medium to dissect social learning
mechanisms in a range of species.
2011-01-01T00:00:00ZPrice, Elizabeth E.The capacity for cumulatively complex and constructive technologies is a
hallmark of human cognitive ability. Many species use tools, yet the breadth,
adaptability, and inventiveness of human tool use distinguishes us. Such complex
technological adaptations require the causal understanding to invent and perfect new
techniques and the ability to copy perceived behaviours. This has led to considerable
research comparing the social learning abilities of chimpanzees and young children on
tool-using tasks, yet experimental studies directly investigating tool modification are rare.
The studies outlined in this thesis sought to assess the social learning abilities of
chimpanzees and children by manipulating both the complexity of a tool modification
method and the amount of information available in a demonstration. Video
demonstrations of conspecifics were used in lieu of live models, in order to manipulate
the quality and quantity of information directly. Both chimpanzees and children presented
with complete information about the modification process learned to combine two tools
together to make a more efficient tool significantly more than those provided with less
information. Unlike chimpanzees, children presented with a more perceptually opaque
method of tool modification (twisting and extending an internal rod) were also able to
socially learn the task, despite the fact that none of the children in the control condition
successfully solved the task. Both children and chimpanzees who solved the task after
seeing a demonstration also persisted in using the socially learned method two-weeks
later, even when it was no longer necessary. These results identify potent social learning
effects in both chimpanzees and children, however, children proved superior to
chimpanzees in observationally learning finer manipulative techniques.
This thesis also provides the first analysis of video stimuli in ravens. To assess the
feasibility of the methodology, ravens were first presented with different types of video
stimuli, varying in terms of the subject identity. Ravens showed a preference for video
footage of other ravens over different species of birds. In a second study, ravens who saw
a conspecific solve a two-step task were more likely to attempt a solution than those who
had not. This represents the first evidence of social learning from a video demonstration
in ravens and further supports the use of this medium to dissect social learning
mechanisms in a range of species.The experience of participating in crowds : shared identity, relatedness and emotionalityNeville, Fergus Gilmourhttps://hdl.handle.net/10023/31122020-07-28T02:02:31Z2012-06-19T00:00:00ZThe aim of this thesis is to extend the social identity model of crowd behaviour (Reicher, 1984,
1987, 1996) by exploring the experience of collective participation, with an emphasis upon
quality of within-crowd social relations (‘relatedness’) and collective emotionality. A multi-method research strategy is employed to study these topics at a variety of crowd events. Studies 1
and 2 use ethnography and retrospective interviews at a student protest and public screenings of
football matches to generate hypotheses for subsequent testing. Study 3 then tests these
hypotheses by means of questionnaire data collected during Study 2. Using an experimental
‘visualisation’ paradigm, Study 4 demonstrates the role of shared identity (and not simply self-categorization) in generating relatedness. Studies 5 and 6 present evidence that groups of high
relatedness participants experience identity-relevant stimuli as more emotionally intense than low
relatedness groups. Study 7 concludes the empirical work by using questionnaire data collected at
political protests to test a model of collective experience based upon the findings of the previous
studies. The thesis argues that a perception of shared identity with co-present others can
positively transform social relations towards relatedness (connectedness, validation and
recognition). Relatedness may then be experienced emotionally, and facilitate the realisation of
group goals which may also have emotional consequences. Strength of social identity is also
noted as an antecedent to group-based emotion. In this way the analysis offers three ways in
which social identity may lead to emotionality of collective experience, contradicting ‘classic’
crowd psychology in which crowd emotion was rooted in a loss of identity. Preliminary evidence
is also presented suggesting that the experience of collective participation may have a role to play
in determining future social identification and participation in co-action.
2012-06-19T00:00:00ZNeville, Fergus GilmourThe aim of this thesis is to extend the social identity model of crowd behaviour (Reicher, 1984,
1987, 1996) by exploring the experience of collective participation, with an emphasis upon
quality of within-crowd social relations (‘relatedness’) and collective emotionality. A multi-method research strategy is employed to study these topics at a variety of crowd events. Studies 1
and 2 use ethnography and retrospective interviews at a student protest and public screenings of
football matches to generate hypotheses for subsequent testing. Study 3 then tests these
hypotheses by means of questionnaire data collected during Study 2. Using an experimental
‘visualisation’ paradigm, Study 4 demonstrates the role of shared identity (and not simply self-categorization) in generating relatedness. Studies 5 and 6 present evidence that groups of high
relatedness participants experience identity-relevant stimuli as more emotionally intense than low
relatedness groups. Study 7 concludes the empirical work by using questionnaire data collected at
political protests to test a model of collective experience based upon the findings of the previous
studies. The thesis argues that a perception of shared identity with co-present others can
positively transform social relations towards relatedness (connectedness, validation and
recognition). Relatedness may then be experienced emotionally, and facilitate the realisation of
group goals which may also have emotional consequences. Strength of social identity is also
noted as an antecedent to group-based emotion. In this way the analysis offers three ways in
which social identity may lead to emotionality of collective experience, contradicting ‘classic’
crowd psychology in which crowd emotion was rooted in a loss of identity. Preliminary evidence
is also presented suggesting that the experience of collective participation may have a role to play
in determining future social identification and participation in co-action.A cognitive approach to the study of culture in wild chimpanzees (Pan troglodytes schweinfurthii)Gruber, Thibaudhttps://hdl.handle.net/10023/31012019-07-01T10:10:36Z2011-11-30T00:00:00ZThe question of animal culture has been of interest for decades. Chimpanzees (Pan
troglodytes) have played a key role in the debate of whether or not it is appropriate to use the
term ‘culture’ to describe animal behaviour and they continue to be one of the prime species
for the study of the origins of human culture. Data suggesting that chimpanzees can be
considered a cultural species continue to accumulate, but this has only enhanced the debate
between proponents and opponents of animal culture. Opponents do not deny that
behavioural diversity exists between different populations of the same species, but they
maintain that such phenomena have little to do with human cultures and may be the result of
genetic and environmental influences. In their view, human cultures are centred on socially
shared sets of ideas, not behavioural traditions. In this thesis, my goal is to tackle this
problem and to investigate whether a cognitive dimension can be found in some behavioural
patterns of chimpanzees that have been put forward as examples of animal culture. To this
end, I examine the different factors that could account for the development of tool use in
animals (genetics, ecology, social). My first empirical contribution is a study of the tool use
behaviour of the chimpanzees’ closest relative, the bonobos, which are known to be limited
tool-users in the wild. I show that captive bonobos are as flexible tool-users as chimpanzees,
suggesting that genetic factors are unlikely to account for differences in tool use behaviour in
the Pan clade. Second, through the use of field experiments, I show that wild chimpanzees
from different Ugandan communities respond to the same apparatus and task in strikingly
different ways. I interpret this finding as an outcome of differences in cultural knowledge,
mainly because the affordances of their immediate environment do not determine their tool
use behaviour. Finally, through a broad ecological and tool use survey of different
chimpanzee communities in Uganda, I show that current ecological differences are poor
predictors of tool use. I conclude that, if ecology plays a role in the development of tool use,
then its influence is that of a selective force. Finally, when reviewing the outcome of this
research I will argue that there is a profound cognitive dimension to tool use in wild
chimpanzees, suggesting that behaviourally based definitions of animal culture may miss a
key feature of the phenomenon, at least in chimpanzees. Chimpanzees are not only a cultural
species, they also have a cultural mind.
2011-11-30T00:00:00ZGruber, ThibaudThe question of animal culture has been of interest for decades. Chimpanzees (Pan
troglodytes) have played a key role in the debate of whether or not it is appropriate to use the
term ‘culture’ to describe animal behaviour and they continue to be one of the prime species
for the study of the origins of human culture. Data suggesting that chimpanzees can be
considered a cultural species continue to accumulate, but this has only enhanced the debate
between proponents and opponents of animal culture. Opponents do not deny that
behavioural diversity exists between different populations of the same species, but they
maintain that such phenomena have little to do with human cultures and may be the result of
genetic and environmental influences. In their view, human cultures are centred on socially
shared sets of ideas, not behavioural traditions. In this thesis, my goal is to tackle this
problem and to investigate whether a cognitive dimension can be found in some behavioural
patterns of chimpanzees that have been put forward as examples of animal culture. To this
end, I examine the different factors that could account for the development of tool use in
animals (genetics, ecology, social). My first empirical contribution is a study of the tool use
behaviour of the chimpanzees’ closest relative, the bonobos, which are known to be limited
tool-users in the wild. I show that captive bonobos are as flexible tool-users as chimpanzees,
suggesting that genetic factors are unlikely to account for differences in tool use behaviour in
the Pan clade. Second, through the use of field experiments, I show that wild chimpanzees
from different Ugandan communities respond to the same apparatus and task in strikingly
different ways. I interpret this finding as an outcome of differences in cultural knowledge,
mainly because the affordances of their immediate environment do not determine their tool
use behaviour. Finally, through a broad ecological and tool use survey of different
chimpanzee communities in Uganda, I show that current ecological differences are poor
predictors of tool use. I conclude that, if ecology plays a role in the development of tool use,
then its influence is that of a selective force. Finally, when reviewing the outcome of this
research I will argue that there is a profound cognitive dimension to tool use in wild
chimpanzees, suggesting that behaviourally based definitions of animal culture may miss a
key feature of the phenomenon, at least in chimpanzees. Chimpanzees are not only a cultural
species, they also have a cultural mind.Learning to use illumination gradients as an unambiguous cue to three dimensional shapeHarding, GlenHarris, JulieBloj, Marinahttps://hdl.handle.net/10023/30772022-04-26T08:30:04Z2012-04-30T00:00:00ZThe luminance and colour gradients across an image are the result of complex interactions between object shape, material and illumination. Using such variations to infer object shape or surface colour is therefore a difficult problem for the visual system. We know that changes to the shape of an object can affect its perceived colour, and that shading gradients confer a sense of shape. Here we investigate if the visual system is able to effectively utilise these gradients as a cue to shape perception, even when additional cues are not available. We tested shape perception of a folded card object that contained illumination gradients in the form of shading and more subtle effects such as inter-reflections. Our results suggest that observers are able to use the gradients to make consistent shape judgements. In order to do this, observers must be given the opportunity to learn suitable assumptions about the lighting and scene. Using a variety of different training conditions, we demonstrate that learning can occur quickly and requires only coarse information. We also establish that learning does not deliver a trivial mapping between gradient and shape; rather learning leads to the acquisition of assumptions about lighting and scene parameters that subsequently allow for gradients to be used as a shape cue. The perceived shape is shown to be consistent for convex and concave versions of the object that exhibit very different shading, and also similar to that delivered by outline, a largely unrelated cue to shape. Overall our results indicate that, although gradients are less reliable than some other cues, the relationship between gradients and shape can be quickly assessed and the gradients therefore used effectively as a visual shape cue.
2012-04-30T00:00:00ZHarding, GlenHarris, JulieBloj, MarinaThe luminance and colour gradients across an image are the result of complex interactions between object shape, material and illumination. Using such variations to infer object shape or surface colour is therefore a difficult problem for the visual system. We know that changes to the shape of an object can affect its perceived colour, and that shading gradients confer a sense of shape. Here we investigate if the visual system is able to effectively utilise these gradients as a cue to shape perception, even when additional cues are not available. We tested shape perception of a folded card object that contained illumination gradients in the form of shading and more subtle effects such as inter-reflections. Our results suggest that observers are able to use the gradients to make consistent shape judgements. In order to do this, observers must be given the opportunity to learn suitable assumptions about the lighting and scene. Using a variety of different training conditions, we demonstrate that learning can occur quickly and requires only coarse information. We also establish that learning does not deliver a trivial mapping between gradient and shape; rather learning leads to the acquisition of assumptions about lighting and scene parameters that subsequently allow for gradients to be used as a shape cue. The perceived shape is shown to be consistent for convex and concave versions of the object that exhibit very different shading, and also similar to that delivered by outline, a largely unrelated cue to shape. Overall our results indicate that, although gradients are less reliable than some other cues, the relationship between gradients and shape can be quickly assessed and the gradients therefore used effectively as a visual shape cue.Visual ageing of human faces in three dimensions using morphable models and projection to latent structuresHunter, David WilliamTiddeman, Bernard Paulhttps://hdl.handle.net/10023/30662023-04-19T00:37:25Z2009-02-01T00:00:00ZWe present an approach to synthesising the effects of ageing on human face images using three-dimensional modelling. We extract a set of three dimensional face models from a set of two-dimensional face images by fitting a Morphable Model. We propose a method to age these face models using Partial Least Squares to extract from the data-set those factors most related to ageing. These ageing related factors are used to train an individually weighted linear model. We show that this is an effective means of producing an aged face image and compare this method to two other linear ageing methods for ageing face models. This is demonstrated both quantitatively and with perceptual evaluation using human raters.
2009-02-01T00:00:00ZHunter, David WilliamTiddeman, Bernard PaulWe present an approach to synthesising the effects of ageing on human face images using three-dimensional modelling. We extract a set of three dimensional face models from a set of two-dimensional face images by fitting a Morphable Model. We propose a method to age these face models using Partial Least Squares to extract from the data-set those factors most related to ageing. These ageing related factors are used to train an individually weighted linear model. We show that this is an effective means of producing an aged face image and compare this method to two other linear ageing methods for ageing face models. This is demonstrated both quantitatively and with perceptual evaluation using human raters.Chimpanzee (Pan troglodytes) gaze following in the informed forager paradigm : analysis with cross correlationsHall, Katherine McGregorhttps://hdl.handle.net/10023/30292022-08-29T13:55:10Z2012-06-19T00:00:00ZI tested two pairs of captive chimpanzees (Pan troglodytes) in the informed forager paradigm: a subordinate saw the location of hidden bait, and then searched with a naïve dominant. This paradigm has tested what subjects know about others’ states of knowledge, but my focus was to determine how subjects used different movement types and different gaze types to modify their competitive tactics.
In particular, I investigated whether chimpanzees follow opponents’ gaze to gain
information. Learning more about how primates use visual information to predict others’ behaviour can shed light on the continuing debate over to what degree apes possess theory of mind capacities.
Previous published studies in this paradigm included narratives of ignorant competitors exploiting informed subjects by following their movement and gaze, and informed subjects avoided this exploitation by walking away from hidden food. The subordinate’s behaviour can be considered tactical deception, which is a good place to seek strong evidence of second-order intentionality.
Analyses with descriptive statistics, however, fail to capture the complexity of these interactions, which range from single decision-making points to larger patterns of following and misleading. I introduced a novel method of statistical analysis, cross correlations, that enabled me to examine behavioural patterns quantitatively that previous authors have only been able to describe in narrative form.
Though previous studies on chimpanzees’ understanding of gaze found that they were
unable to use (human-given) gaze cues to locate hidden food, the subjects I tested followed their conspecific opponent’s gaze, and used information gained from the gaze interaction to modify their own movement towards the hidden bait. Dominants adjusted their physical following of the subordinates as the interaction progressed, which reflected their changed states of knowledge. Subordinates used their movement and gaze differentially to manipulate dominants’ behaviour, by withholding information and by recruiting towards a less-preferred bait.
2012-06-19T00:00:00ZHall, Katherine McGregorI tested two pairs of captive chimpanzees (Pan troglodytes) in the informed forager paradigm: a subordinate saw the location of hidden bait, and then searched with a naïve dominant. This paradigm has tested what subjects know about others’ states of knowledge, but my focus was to determine how subjects used different movement types and different gaze types to modify their competitive tactics.
In particular, I investigated whether chimpanzees follow opponents’ gaze to gain
information. Learning more about how primates use visual information to predict others’ behaviour can shed light on the continuing debate over to what degree apes possess theory of mind capacities.
Previous published studies in this paradigm included narratives of ignorant competitors exploiting informed subjects by following their movement and gaze, and informed subjects avoided this exploitation by walking away from hidden food. The subordinate’s behaviour can be considered tactical deception, which is a good place to seek strong evidence of second-order intentionality.
Analyses with descriptive statistics, however, fail to capture the complexity of these interactions, which range from single decision-making points to larger patterns of following and misleading. I introduced a novel method of statistical analysis, cross correlations, that enabled me to examine behavioural patterns quantitatively that previous authors have only been able to describe in narrative form.
Though previous studies on chimpanzees’ understanding of gaze found that they were
unable to use (human-given) gaze cues to locate hidden food, the subjects I tested followed their conspecific opponent’s gaze, and used information gained from the gaze interaction to modify their own movement towards the hidden bait. Dominants adjusted their physical following of the subordinates as the interaction progressed, which reflected their changed states of knowledge. Subordinates used their movement and gaze differentially to manipulate dominants’ behaviour, by withholding information and by recruiting towards a less-preferred bait.Interpreting the neural code with formal concept analysisEndres, DFoldiak, Peterhttps://hdl.handle.net/10023/29912023-04-19T00:37:17Z2009-01-01T00:00:00ZWe propose a novel application of Formal Concept Analysis (FCA) to neural decoding: instead of just trying to figure out which stimulus was presented, we demonstrate how to explore the semantic relationships in the neural representation of large sets of stimuli. FCA provides a way of displaying and interpreting such relationships via concept lattices. We explore the effects of neural code sparsity on the lattice. We then analyze neurophysiological data from high-level visual cortical area STSa, using an exact Bayesian approach to construct the formal context needed by FCA. Prominent features of the resulting concept lattices are discussed, including hierarchical face representation and indications for a product-of-experts code in real neurons.
This contribution is in volume 1 of 3 for this title.
2009-01-01T00:00:00ZEndres, DFoldiak, PeterWe propose a novel application of Formal Concept Analysis (FCA) to neural decoding: instead of just trying to figure out which stimulus was presented, we demonstrate how to explore the semantic relationships in the neural representation of large sets of stimuli. FCA provides a way of displaying and interpreting such relationships via concept lattices. We explore the effects of neural code sparsity on the lattice. We then analyze neurophysiological data from high-level visual cortical area STSa, using an exact Bayesian approach to construct the formal context needed by FCA. Prominent features of the resulting concept lattices are discussed, including hierarchical face representation and indications for a product-of-experts code in real neurons.Imitation, play and theory of mind in autism : an observational and experimental studyBrown, Julie D.https://hdl.handle.net/10023/29422019-04-01T10:41:42Z1996-01-01T00:00:00ZThis observational and experimental study takes the Intersubjectivity Theory
of Rogers and Pennington (1991), as the guiding line by which to investigate
imitation in autism. A deficit in imitation in early childhood is the principal aspect of
this theory which distinguishes it from other major theories such as those of Baron-
Cohen et al. (1985) and Hobson (1986).
With much debate over the existence of a general deficit in imitation, this
study aimed first to test for different types of imitation (including those
differentiated by Piaget (1962), such as vocal, immediate and deferred imitation) and
second, to examine other deficits linked to imitation in Roger and Pennington's
theory - emotion perception, joint attention, theory of mind and play. The effect of
age was also investigated. Rogers and Pennington (1991) predicted that young
autistic children would show a profile of deficits including impaired imitation,
emotion sharing, joint attention and pretend play while older children and adults
would show impaired "theory of mind", emotion sharing and language pragmatics,
relative to controls.
In an observational study autistic children and adults showed less social
interaction with peers, more manipulative play, less symbolic play in some
comparisons and less evidence of mental state understanding but few differences in
imitation, compared to children with learning disabilities and normal 3-4 year old
and 5-6 year old children.
Virtually the same samples were then tested experimentally for the ability to
imitate. This was done for (1) elicited imitation (including vocal, simple body
movements and symbolic actions, with and without objects), (2) spontaneous,
problem-solving imitation and (3) deferred imitation. In addition, spontaneous,
elicited and instructed play was tested and visual perspective-taking, joint attention,
false-belief and emotion recognition. No general deficit for imitation in school-age
autistic children and autistic adults was found, although a younger group (CA 4 - 7
years) of autistic children did significantly worse on all aspects of the task. Scores
were lower on deferred imitation and on spontaneous, problem-solving imitation for
the autistic groups and certain categories of actions in the elicited task proved more
difficult for the autistic children, namely those requiring symbolic ability.
Previous findings on joint attention, false-belief and emotion perception
were, for the most part, confirmed, although no links between any of these
behaviours and imitation were evident from examination of individual profiles. In
addition, a picture of inconsistency across tasks emerged. However, some evidence
was found for Rogers and Pennington's theory at a crude level, in that it was the
youngest children who had most problems with imitation, symbolic play, and
emotion recognition, relative to controls. It is concluded that although imitation may
be lacking in early autistic development, Rogers and Pennington's theory may not be
an altogether satisfactory way of explaining its contribution to the autistic disorder
and is, in fact, very difficult to test.
1996-01-01T00:00:00ZBrown, Julie D.This observational and experimental study takes the Intersubjectivity Theory
of Rogers and Pennington (1991), as the guiding line by which to investigate
imitation in autism. A deficit in imitation in early childhood is the principal aspect of
this theory which distinguishes it from other major theories such as those of Baron-
Cohen et al. (1985) and Hobson (1986).
With much debate over the existence of a general deficit in imitation, this
study aimed first to test for different types of imitation (including those
differentiated by Piaget (1962), such as vocal, immediate and deferred imitation) and
second, to examine other deficits linked to imitation in Roger and Pennington's
theory - emotion perception, joint attention, theory of mind and play. The effect of
age was also investigated. Rogers and Pennington (1991) predicted that young
autistic children would show a profile of deficits including impaired imitation,
emotion sharing, joint attention and pretend play while older children and adults
would show impaired "theory of mind", emotion sharing and language pragmatics,
relative to controls.
In an observational study autistic children and adults showed less social
interaction with peers, more manipulative play, less symbolic play in some
comparisons and less evidence of mental state understanding but few differences in
imitation, compared to children with learning disabilities and normal 3-4 year old
and 5-6 year old children.
Virtually the same samples were then tested experimentally for the ability to
imitate. This was done for (1) elicited imitation (including vocal, simple body
movements and symbolic actions, with and without objects), (2) spontaneous,
problem-solving imitation and (3) deferred imitation. In addition, spontaneous,
elicited and instructed play was tested and visual perspective-taking, joint attention,
false-belief and emotion recognition. No general deficit for imitation in school-age
autistic children and autistic adults was found, although a younger group (CA 4 - 7
years) of autistic children did significantly worse on all aspects of the task. Scores
were lower on deferred imitation and on spontaneous, problem-solving imitation for
the autistic groups and certain categories of actions in the elicited task proved more
difficult for the autistic children, namely those requiring symbolic ability.
Previous findings on joint attention, false-belief and emotion perception
were, for the most part, confirmed, although no links between any of these
behaviours and imitation were evident from examination of individual profiles. In
addition, a picture of inconsistency across tasks emerged. However, some evidence
was found for Rogers and Pennington's theory at a crude level, in that it was the
youngest children who had most problems with imitation, symbolic play, and
emotion recognition, relative to controls. It is concluded that although imitation may
be lacking in early autistic development, Rogers and Pennington's theory may not be
an altogether satisfactory way of explaining its contribution to the autistic disorder
and is, in fact, very difficult to test.Socio-spatial isomorphismMacBride, S. J. C.https://hdl.handle.net/10023/28942019-04-01T10:41:04Z1999-01-01T00:00:00ZIt is contended that space can act as a metaphor for social relationships. The
thesis draws on schema theory from cognitive psychology to explain how the
affective qualities of social stimuli serve to bias the 'cognitive maps' of individuals.
Supporting evidence is cited from the fields of cognitive, social, environmental and
neuro-psychology.
The metaphor is tested experimentally from a micro-spatial level (e. g. spatial
locations of characters in a photograph) up to a macro-spatial level (spatial
locations of towns). The affective valence of the stimuli used were either a priori
based (e. g. homes of people already known to the subject, perceived religious
predominance of towns in a sectarian setting) or influenced by the experimenter
(e. g. captions purporting to inform representations of social scenes in photographs
derived from newspapers and magazines).
Distortion of perceived distances (between subject and stimuli and between stimuli)
form the dependent variable in each experiment.
Results in all experiments indicated a strong tendency for the valence of stimuli to
bias people in their distance estimations. Relative overestimation of distance was
observed for stimuli perceived to be negatively valenced and the reverse for those
stimuli perceived to be positively valenced. In a final experiment, distance
estimations were examined between a variety of human figures photographed in
'real-world' social encounters. The results were in line with Social Identity Theory,
with overestimation observed between groups and underestimation within groups.
Results throughout are interpreted in relation to the 'socio-spatial schema'
metaphor.
1999-01-01T00:00:00ZMacBride, S. J. C.It is contended that space can act as a metaphor for social relationships. The
thesis draws on schema theory from cognitive psychology to explain how the
affective qualities of social stimuli serve to bias the 'cognitive maps' of individuals.
Supporting evidence is cited from the fields of cognitive, social, environmental and
neuro-psychology.
The metaphor is tested experimentally from a micro-spatial level (e. g. spatial
locations of characters in a photograph) up to a macro-spatial level (spatial
locations of towns). The affective valence of the stimuli used were either a priori
based (e. g. homes of people already known to the subject, perceived religious
predominance of towns in a sectarian setting) or influenced by the experimenter
(e. g. captions purporting to inform representations of social scenes in photographs
derived from newspapers and magazines).
Distortion of perceived distances (between subject and stimuli and between stimuli)
form the dependent variable in each experiment.
Results in all experiments indicated a strong tendency for the valence of stimuli to
bias people in their distance estimations. Relative overestimation of distance was
observed for stimuli perceived to be negatively valenced and the reverse for those
stimuli perceived to be positively valenced. In a final experiment, distance
estimations were examined between a variety of human figures photographed in
'real-world' social encounters. The results were in line with Social Identity Theory,
with overestimation observed between groups and underestimation within groups.
Results throughout are interpreted in relation to the 'socio-spatial schema'
metaphor.Spider monkey (Ateles geoffroyi yucatanensis) travel patterns in a subtropical forest of Yucatan, MexicoValero, Alejandrahttps://hdl.handle.net/10023/28352019-07-01T10:13:13Z2004-01-01T00:00:00ZA 12-month study of the ranging behaviour of 11 spider monkeys (Ateles geoffroyi
yucatanensis) was undertaken at the Otochma' ax Yetel Kooh nature reserve in the state
of Yucatan, Mexico. The aims were: 1) to evaluate the relationship between ranging
patterns of the monkeys and ecological features i.e. climate and food distribution, 2) to
assess the efficiency of ranging patterns, and 3) to test the hypothesis that spider monkeys
navigate between important sources through spatial memory of key locations. A focal
animal was followed daily for as long as possible and details of its ranging patterns
recorded by entering positional fixes with a GPS receiver. Behavioural states were
included in the observations to link them with the geographical information recorded
simultaneously. The results revealed that the ranging patterns of spider monkeys at the
study site were determined by the availability of key species of fruit in the area. Ranging
was efficient, as evidenced by the fact that in most instances - particularly in the dry
season when food was scarce - (1) spider monkeys moved in straight lines to distant food
sources, (2) were able to orient their movement toward a food source at distances that
could not have been in sight from the point where directed movement originated, and (3)
the successive organisation of these linear segments was consistently forward, suggesting
an ability to plan ahead of the next food source visited. I present these results as evidence
of the use of spatial memory to move efficiently between important sources in their
environment, and I argue in favour of higher-level spatial abilities in this species of New
World monkeys.
2004-01-01T00:00:00ZValero, AlejandraA 12-month study of the ranging behaviour of 11 spider monkeys (Ateles geoffroyi
yucatanensis) was undertaken at the Otochma' ax Yetel Kooh nature reserve in the state
of Yucatan, Mexico. The aims were: 1) to evaluate the relationship between ranging
patterns of the monkeys and ecological features i.e. climate and food distribution, 2) to
assess the efficiency of ranging patterns, and 3) to test the hypothesis that spider monkeys
navigate between important sources through spatial memory of key locations. A focal
animal was followed daily for as long as possible and details of its ranging patterns
recorded by entering positional fixes with a GPS receiver. Behavioural states were
included in the observations to link them with the geographical information recorded
simultaneously. The results revealed that the ranging patterns of spider monkeys at the
study site were determined by the availability of key species of fruit in the area. Ranging
was efficient, as evidenced by the fact that in most instances - particularly in the dry
season when food was scarce - (1) spider monkeys moved in straight lines to distant food
sources, (2) were able to orient their movement toward a food source at distances that
could not have been in sight from the point where directed movement originated, and (3)
the successive organisation of these linear segments was consistently forward, suggesting
an ability to plan ahead of the next food source visited. I present these results as evidence
of the use of spatial memory to move efficiently between important sources in their
environment, and I argue in favour of higher-level spatial abilities in this species of New
World monkeys.Feeding, ranging and social organisation of the Guinea baboonSharman, Martin Johnhttps://hdl.handle.net/10023/28332019-04-01T10:40:37Z1982-01-01T00:00:00ZBefore this study, the Guinea or Western baboon, Papio papio, was almost unknown in its natural environment. This thesis reports a nineteen-month field study of two troops of P. papio carried out in south-eastern Senegal. The monkeys were followed on foot, and aspects of their feeding, ranging and social behaviour were recorded.
The troops were censused whenever possible. Both study groups, and other troops in the area, were found to be unusually large by comparison with other known troops in the genus, and although their age-sex compositions were not exceptional, there was some indication that recruitment into the adult population was low.
The activity budgets of both troops were similar, and members of both troops spent more time moving and feeding in the dry season than they did in the wet, when they spent more time in social behaviour. These differences were probably related to seasonal changes in productivity, which were large, since no rain feel in six months of the year.
The home range of one of the study troops covered about 45 to 50 square kilometres, while the other troop, whose home range was less well known, ranged over about 18 to 20 square kilometres. There were no seasonal differences in the mean distance travelled per day by either troop, although there was great daily variation about the mean of roughly 8 kilometres. This distance was greater than that travelled by most other troops of baboons, and was ascribed to low productivity in the dry season and large troops in the wet. The troops visited some habitats more frequently than they did others, and moved more slowly through those that they visited frequently than through those that they visited frequently than through those they visited less frequently. In the dry season both troops visited areas in which there was relatively dense shade more frequently than they did areas with little shade. In the wet season they avoided areas in which variability was poor.
Sleeping sites were found to have a profound influence on the ranging patterns of the baboons, with usage of the home ranges being inversely proportional to the square of the distance from the nearest sleeping site. The baboons apparently chose to sleep in trees which afforded them protection against predation. The sleeping sites were restricted to places in which there was permanent water.
The baboons were largely frugivorous. In this they resembled baboon troops studied in other areas. Their diet changed throughout the year, as various plants fruited or seeded, and was more diverse in the wet season, when a wider variety of foods was available. More than a hundred different food items were known to be eaten, and the number of known food types increased throughout the study. Animals in their diet were mostly invertebrates found beneath boulders, but some vertebrates were also eaten.
The social organisation and mating system of these baboons were compared with those of the other baboons, including Theropithecus gelada. It was unlikely that they lived in a society in which adult females were constrained to mate with only one male, as are females in two other species of baboon. Instead, there appeared to be competition for sexual partners, with the formation of consortships between adults during the time of the female’s oestrus. Adult males groomed each other in this species, which is uncommon in baboons with competitive mating, except at times of stress.
1982-01-01T00:00:00ZSharman, Martin JohnBefore this study, the Guinea or Western baboon, Papio papio, was almost unknown in its natural environment. This thesis reports a nineteen-month field study of two troops of P. papio carried out in south-eastern Senegal. The monkeys were followed on foot, and aspects of their feeding, ranging and social behaviour were recorded.
The troops were censused whenever possible. Both study groups, and other troops in the area, were found to be unusually large by comparison with other known troops in the genus, and although their age-sex compositions were not exceptional, there was some indication that recruitment into the adult population was low.
The activity budgets of both troops were similar, and members of both troops spent more time moving and feeding in the dry season than they did in the wet, when they spent more time in social behaviour. These differences were probably related to seasonal changes in productivity, which were large, since no rain feel in six months of the year.
The home range of one of the study troops covered about 45 to 50 square kilometres, while the other troop, whose home range was less well known, ranged over about 18 to 20 square kilometres. There were no seasonal differences in the mean distance travelled per day by either troop, although there was great daily variation about the mean of roughly 8 kilometres. This distance was greater than that travelled by most other troops of baboons, and was ascribed to low productivity in the dry season and large troops in the wet. The troops visited some habitats more frequently than they did others, and moved more slowly through those that they visited frequently than through those that they visited frequently than through those they visited less frequently. In the dry season both troops visited areas in which there was relatively dense shade more frequently than they did areas with little shade. In the wet season they avoided areas in which variability was poor.
Sleeping sites were found to have a profound influence on the ranging patterns of the baboons, with usage of the home ranges being inversely proportional to the square of the distance from the nearest sleeping site. The baboons apparently chose to sleep in trees which afforded them protection against predation. The sleeping sites were restricted to places in which there was permanent water.
The baboons were largely frugivorous. In this they resembled baboon troops studied in other areas. Their diet changed throughout the year, as various plants fruited or seeded, and was more diverse in the wet season, when a wider variety of foods was available. More than a hundred different food items were known to be eaten, and the number of known food types increased throughout the study. Animals in their diet were mostly invertebrates found beneath boulders, but some vertebrates were also eaten.
The social organisation and mating system of these baboons were compared with those of the other baboons, including Theropithecus gelada. It was unlikely that they lived in a society in which adult females were constrained to mate with only one male, as are females in two other species of baboon. Instead, there appeared to be competition for sexual partners, with the formation of consortships between adults during the time of the female’s oestrus. Adult males groomed each other in this species, which is uncommon in baboons with competitive mating, except at times of stress.An investigation into the function of single-neuron activity in the mesoaccumbens dopamine system of the ratWilson, David Ian Greighttps://hdl.handle.net/10023/28282019-07-01T10:12:13Z2005-01-01T00:00:00ZThe mesoaccumbens dopamine system has been implicated in many basic
psychological processes (e.g. "wanting" and "liking") and illnesses (e.g. addiction,
depression, schizophrenia). However, the precise computational functions of
nucleus accumbens and dopamine neurons within the system remain unknown.
In this thesis, we test some of the current hypotheses regarding the function of
this system using a behavioural neurophysiology approach in the rat. The first
question we wanted to answer was whether nucleus accumbens neurons
process reward-predictive stimuli (e.g. conditioned reinforcers) and reward
delivery differently, since previous studies report equivocal findings. To do so, we
trained thirsty rats to bar-press on a second-order schedule of saccharin
reinforcement, within which the temporal pattern of rats' bar-pressing was
reinforced by presentations of a conditioned reinforcer and primary reinforcer
(reward). We found that nucleus accumbens neurons typically responded to
these conditioned and primary reinforcers with opposite sign, which suggests
they were processed differently. We were not sure whether responses to
conditioned reinforcers encoded reward-prediction or facilitated a behavioural
switch in the rat's behaviour. Indeed, since studies using a variety of
experimental techniques have implicated the mesoaccumbens dopamine system
in both reward prediction and behavioural switching, we sought to test whether
neurons in the nucleus accumbens and dopamine-rich areas of the midbrain
respond to outcome-associated stimuli to predict reward or switch behaviour. We
found both sets of neurons predominantly did the former. Finally, to understand
more about reward consummatory responses from both sets of neurons, we
developed a rat behavioural task providing measures of reward "wanting" and
"liking". In conclusion, on the basis of our data, the most parsimonious
explanation for the function of the mesoaccumbens dopamine system is that it
acts to modulate goal-seeking behaviour. Further research is required to identify
the function of the interactions between nucleus accumbens and dopamine
neurons during goal-seeking and goal consumption.
2005-01-01T00:00:00ZWilson, David Ian GreigThe mesoaccumbens dopamine system has been implicated in many basic
psychological processes (e.g. "wanting" and "liking") and illnesses (e.g. addiction,
depression, schizophrenia). However, the precise computational functions of
nucleus accumbens and dopamine neurons within the system remain unknown.
In this thesis, we test some of the current hypotheses regarding the function of
this system using a behavioural neurophysiology approach in the rat. The first
question we wanted to answer was whether nucleus accumbens neurons
process reward-predictive stimuli (e.g. conditioned reinforcers) and reward
delivery differently, since previous studies report equivocal findings. To do so, we
trained thirsty rats to bar-press on a second-order schedule of saccharin
reinforcement, within which the temporal pattern of rats' bar-pressing was
reinforced by presentations of a conditioned reinforcer and primary reinforcer
(reward). We found that nucleus accumbens neurons typically responded to
these conditioned and primary reinforcers with opposite sign, which suggests
they were processed differently. We were not sure whether responses to
conditioned reinforcers encoded reward-prediction or facilitated a behavioural
switch in the rat's behaviour. Indeed, since studies using a variety of
experimental techniques have implicated the mesoaccumbens dopamine system
in both reward prediction and behavioural switching, we sought to test whether
neurons in the nucleus accumbens and dopamine-rich areas of the midbrain
respond to outcome-associated stimuli to predict reward or switch behaviour. We
found both sets of neurons predominantly did the former. Finally, to understand
more about reward consummatory responses from both sets of neurons, we
developed a rat behavioural task providing measures of reward "wanting" and
"liking". In conclusion, on the basis of our data, the most parsimonious
explanation for the function of the mesoaccumbens dopamine system is that it
acts to modulate goal-seeking behaviour. Further research is required to identify
the function of the interactions between nucleus accumbens and dopamine
neurons during goal-seeking and goal consumption.An investigation into some aspects of the development of religious thinking in children aged between six and eleven yearsMurphy, Roger John Lloydhttps://hdl.handle.net/10023/28032019-07-01T10:08:04Z1979-01-01T00:00:00ZChildren's thinking has been described by Piaget and others in general
terms, which suggest that there are major developmental changes that
affect children's thinking at various stages of their development.
Some criticisms of Piaget's theory have related to his approach to
describing children's thinking as a context free phenomenon. In
relation to this point, arguments have been put forward for the need
to investigate the development of children's thinking, within particular
content areas, and the investigations reported in this thesis have concentrated on the development of religious thinking of children aged from
~6 to 11 years.
A review of previous investigations into this area of children's
thought development reveals major shortcomings, both in the experimental
approaches used and in the theories that have been constructed. In
particular it is argued that there has been a tendency for investigators to propose stage development theories on the basis of inadequate
results. It is argued that there is a need for investigations which
approach this problem from new directions. As a first step, a series
of investigations, which employ a variety of approaches and which
investigate various cognitive and semantic factors that may influence
the development of religious thinking in children, are presented.
The investigations that are reported involved individual interviews
with 440 children, in the age range from 6 to 11 years. A variety
of experimental techniques were employed, including those investigating the children's understanding of various biblical parables,
their understanding of the meaning of words used in religious discourse,
their conception of historical time and ability to sequentially order
events in time, and the way that these factors affected their understanding of religious ideas.
The results of the investigations are discussed in terms of the variety
of aspects, which they reveal, relating to the development of religious
thinking in children. It is argued that this evidence does not support
the idea of the development of religious thinking being a unidimensional
stage related process; however, the evidence collected from these
studies is insufficient to form the basis of an alternative model. It
is argued that future studies that follow this approach will be necessary
if a satisfactory theory is to be constructed.
The educational implications of these findings are discussed and it is
argued that certain curriculum changes in the area of religious
education may have been made on the basis of insufficient evidence and
inadequate theories.
1979-01-01T00:00:00ZMurphy, Roger John LloydChildren's thinking has been described by Piaget and others in general
terms, which suggest that there are major developmental changes that
affect children's thinking at various stages of their development.
Some criticisms of Piaget's theory have related to his approach to
describing children's thinking as a context free phenomenon. In
relation to this point, arguments have been put forward for the need
to investigate the development of children's thinking, within particular
content areas, and the investigations reported in this thesis have concentrated on the development of religious thinking of children aged from
~6 to 11 years.
A review of previous investigations into this area of children's
thought development reveals major shortcomings, both in the experimental
approaches used and in the theories that have been constructed. In
particular it is argued that there has been a tendency for investigators to propose stage development theories on the basis of inadequate
results. It is argued that there is a need for investigations which
approach this problem from new directions. As a first step, a series
of investigations, which employ a variety of approaches and which
investigate various cognitive and semantic factors that may influence
the development of religious thinking in children, are presented.
The investigations that are reported involved individual interviews
with 440 children, in the age range from 6 to 11 years. A variety
of experimental techniques were employed, including those investigating the children's understanding of various biblical parables,
their understanding of the meaning of words used in religious discourse,
their conception of historical time and ability to sequentially order
events in time, and the way that these factors affected their understanding of religious ideas.
The results of the investigations are discussed in terms of the variety
of aspects, which they reveal, relating to the development of religious
thinking in children. It is argued that this evidence does not support
the idea of the development of religious thinking being a unidimensional
stage related process; however, the evidence collected from these
studies is insufficient to form the basis of an alternative model. It
is argued that future studies that follow this approach will be necessary
if a satisfactory theory is to be constructed.
The educational implications of these findings are discussed and it is
argued that certain curriculum changes in the area of religious
education may have been made on the basis of insufficient evidence and
inadequate theories.Perception of relative depth interval : Systematic biases in perceived depthHarris, JulieChopin, AdrienZeiner, Katharina MariaHibbard, Paul Barryhttps://hdl.handle.net/10023/27492022-07-08T10:30:03Z2012-01-01T00:00:00ZGiven an estimate of the binocular disparity between a pair of points and an estimate of the viewing distance, or knowledge of eye position, it should be possible to obtain an estimate of their depth separation. Here we show that, when points are arranged in different vertical geometric configurations across two intervals, many observers find this task difficult. Those who can do the task tend to perceive the depth interval in one configuration as very different from depth in the other configuration. We explore two plausible explanations for this effect. The first is the tilt of the empirical vertical horopter: Points perceived along an apparently vertical line correspond to a physical line of points tilted backwards in space. Second, the eyes can rotate in response to a particular stimulus. Without compensation for this rotation, biases in depth perception would result. We measured cyclovergence indirectly, using a standard psychophysical task, while observers viewed our depth configuration. Biases predicted from error due either to cyclovergence or to the tilted vertical horopter were not consistent with the depth configuration results. Our data suggest that, even for the simplest scenes, we do not have ready access to metric depth from binocular disparity.
2012-01-01T00:00:00ZHarris, JulieChopin, AdrienZeiner, Katharina MariaHibbard, Paul BarryGiven an estimate of the binocular disparity between a pair of points and an estimate of the viewing distance, or knowledge of eye position, it should be possible to obtain an estimate of their depth separation. Here we show that, when points are arranged in different vertical geometric configurations across two intervals, many observers find this task difficult. Those who can do the task tend to perceive the depth interval in one configuration as very different from depth in the other configuration. We explore two plausible explanations for this effect. The first is the tilt of the empirical vertical horopter: Points perceived along an apparently vertical line correspond to a physical line of points tilted backwards in space. Second, the eyes can rotate in response to a particular stimulus. Without compensation for this rotation, biases in depth perception would result. We measured cyclovergence indirectly, using a standard psychophysical task, while observers viewed our depth configuration. Biases predicted from error due either to cyclovergence or to the tilted vertical horopter were not consistent with the depth configuration results. Our data suggest that, even for the simplest scenes, we do not have ready access to metric depth from binocular disparity.What visual information is used for stereoscopic depth displacement discrimination?Nefs, HaroldHarris, Juliehttps://hdl.handle.net/10023/27462023-04-18T09:43:04Z2010-01-01T00:00:00ZThere are two ways to detect a displacement in stereoscopic depth, namely by monitoring the change in disparity over time (CDOT) or by monitoring the inter-ocular velocity difference (IOVD). Though previous studies have attempted to understand which cue is most significant for the visual system, none have designed stimuli that provide a comparison in terms of relative efficiency between them. Here we used two-frame motion and random dot noise to deliver equivalent strengths of CDOT and IOVD information to the visual system. Using three kinds of random dot stimuli, we were able to isolate CDOT or IOVD or deliver both simultaneously. The proportion of dots delivering CDOT or IOVD signals could be varied, and we defined discrimination threshold as the proportion needed to detect the direction of displacement (towards or away)1. Thresholds were similar for stimuli containing CDOT only, and containing both CDOT and IOVD, but only one participant was able to consistently perceive the displacement for stimuli containing only IOVD. We also investigated the effect of disparity pedestals on discrimination. Performance was best when the displacement crossed the reference plane, but was not significantly different for stimuli containing CDOT only, or containing both CDOT and IOVD. When stimuli are specifically designed to provide equivalent two-frame motion or disparity-change, few participants can reliably detect displacement when IOVD is the only cue. This challenges the notion that IOVD is involved in the discrimination of direction of displacement in two-frame motion displays.
2010-01-01T00:00:00ZNefs, HaroldHarris, JulieThere are two ways to detect a displacement in stereoscopic depth, namely by monitoring the change in disparity over time (CDOT) or by monitoring the inter-ocular velocity difference (IOVD). Though previous studies have attempted to understand which cue is most significant for the visual system, none have designed stimuli that provide a comparison in terms of relative efficiency between them. Here we used two-frame motion and random dot noise to deliver equivalent strengths of CDOT and IOVD information to the visual system. Using three kinds of random dot stimuli, we were able to isolate CDOT or IOVD or deliver both simultaneously. The proportion of dots delivering CDOT or IOVD signals could be varied, and we defined discrimination threshold as the proportion needed to detect the direction of displacement (towards or away)1. Thresholds were similar for stimuli containing CDOT only, and containing both CDOT and IOVD, but only one participant was able to consistently perceive the displacement for stimuli containing only IOVD. We also investigated the effect of disparity pedestals on discrimination. Performance was best when the displacement crossed the reference plane, but was not significantly different for stimuli containing CDOT only, or containing both CDOT and IOVD. When stimuli are specifically designed to provide equivalent two-frame motion or disparity-change, few participants can reliably detect displacement when IOVD is the only cue. This challenges the notion that IOVD is involved in the discrimination of direction of displacement in two-frame motion displays.The behaviour and ecology of domestic cats (Felis catus L.)Panaman, Rogerhttps://hdl.handle.net/10023/27302019-04-01T10:41:08Z1984-01-01T00:00:00ZThis thesis is a reconnaissance of the behavioural ecology of domestic cats. The principal subjects were two groups of farm cats. There was also a group of captive cats and a house cat. The study differs from all previous ones in that the cats were tame and therefore could be shadowed and observed for long periods at all hours. It deals with (1) activity patterns and activity budget, (2) use of space and social behaviour, (3) scent communication, (4) foraging and (5) population dynamics.
1984-01-01T00:00:00ZPanaman, RogerThis thesis is a reconnaissance of the behavioural ecology of domestic cats. The principal subjects were two groups of farm cats. There was also a group of captive cats and a house cat. The study differs from all previous ones in that the cats were tame and therefore could be shadowed and observed for long periods at all hours. It deals with (1) activity patterns and activity budget, (2) use of space and social behaviour, (3) scent communication, (4) foraging and (5) population dynamics.Cognitive aspects of travel and food location by chimpanzees (Pan troglodytes schweinfurthii) of the Budongo Forest Reserve, UgandaBates, Lucyhttps://hdl.handle.net/10023/26972019-04-01T10:40:24Z2005-01-01T00:00:00ZFinding food in tropical forests poses a potentially major problem for chimpanzees, whose
ranging is thought primarily to be directed at locating suitable food resources: (1)
chimpanzees are frugivorous, large bodied and live in large home ranges; (2) they lack
specialised sensory or locomotor abilities, and terrestrial travel is known to be costly; but
(3) fruits are randomly distributed in space and time. Evidence from studies of captive
individuals suggests chimpanzees are capable of remembering the locations of out of sight
resources and can compute least distance routes to these resources, but whether this ability
translates to the natural foraging behaviour of wild chimpanzees has never been
investigated. My observational study was designed to assess how the chimpanzees (Pan
troglodytes schweinfurthii) of Budongo Forest, Uganda, locate these patchy resources.
I mapped the routes of 14 focal individuals over a 12-month period. I considered how
these foraging routes were structured by breaking the path into segments of travel between
resources. Consecutive segments of travel between resources were found not to be
independent, but assembled into "super-segments" that take in a number of resources along
one trajectory. These super-segments are not necessarily directed towards feeding
resources, however: travel is not always food directed. Comparisons of actual chimpanzee
routes with randomly generated simulations suggest most individuals do not attempt to
minimise their travel distances. There is evidence to suggest energetically stressed
individuals can remember the locations of recently visited food resources and return to
these patches in order to minimise travel distances when necessary, but overall, food is not
difficult to find for this community of chimpanzees. I propose this is because males defend
a territory with super-abundant food resources, meaning availability is not a limiting factor
of foraging. Male chimpanzees can be characterised as convenience feeders, taking food
whilst satisfying other, social needs.
2005-01-01T00:00:00ZBates, LucyFinding food in tropical forests poses a potentially major problem for chimpanzees, whose
ranging is thought primarily to be directed at locating suitable food resources: (1)
chimpanzees are frugivorous, large bodied and live in large home ranges; (2) they lack
specialised sensory or locomotor abilities, and terrestrial travel is known to be costly; but
(3) fruits are randomly distributed in space and time. Evidence from studies of captive
individuals suggests chimpanzees are capable of remembering the locations of out of sight
resources and can compute least distance routes to these resources, but whether this ability
translates to the natural foraging behaviour of wild chimpanzees has never been
investigated. My observational study was designed to assess how the chimpanzees (Pan
troglodytes schweinfurthii) of Budongo Forest, Uganda, locate these patchy resources.
I mapped the routes of 14 focal individuals over a 12-month period. I considered how
these foraging routes were structured by breaking the path into segments of travel between
resources. Consecutive segments of travel between resources were found not to be
independent, but assembled into "super-segments" that take in a number of resources along
one trajectory. These super-segments are not necessarily directed towards feeding
resources, however: travel is not always food directed. Comparisons of actual chimpanzee
routes with randomly generated simulations suggest most individuals do not attempt to
minimise their travel distances. There is evidence to suggest energetically stressed
individuals can remember the locations of recently visited food resources and return to
these patches in order to minimise travel distances when necessary, but overall, food is not
difficult to find for this community of chimpanzees. I propose this is because males defend
a territory with super-abundant food resources, meaning availability is not a limiting factor
of foraging. Male chimpanzees can be characterised as convenience feeders, taking food
whilst satisfying other, social needs.Emotion-related information processing biases associated with depression in childhoodDrummond, Lyndsey Elizabethhttps://hdl.handle.net/10023/26572019-04-01T10:41:03Z2006-01-01T00:00:00ZFew studies have examined depression in children from an Information Processing (IP)
perspective. In this thesis a number of domains of IP (known to be associated with adult
depression)are examined in children and adolescents, in particular, autobiographical memory
specificity in both clinical and non-clinical samples. Foremost, overgeneral memory (OGM)
was found for the first time, to be characteristic of dysphoric (Study 1) and clinically
depressed children (Study 2). Similarity in the extent of the OGM bias in depressed and
dysphoric children was observed. OGM was also comparable across child, adolescent and
adult depressed groups (Study 2). Second, OGM predicted depressive symptoms in children
during a stressful life event, in the first longitudinal diathesis-stress investigation of OGM to
date (Study 3). OGM was also linked for the first time to an overgeneral thinking style and to
a depressive attributional style (Study 3) thereby offering possible mechanistic insight in
OGM. Third, in support of Williams' (1996) developmental origins hypothesis, OGM was
also demonstrated in children in residential care who had suffered significant independently
verified negative life events (Study 5). OGM in these youth was positively correlated with
deficits in social problem solving and facial-affect identification, in part contextualizing OGM
in children alongside depresso-typical biases. Performance on the AMT also varied as a
function of severity of abuse with more abused children demonstrating less OGM -a recency
memorial coping strategy is proposed to account for this effect. Fourth, a new measure of EF
was introduced and highlights the importance of encoding preferences in explaining 0GM
(Studies I& 5). Finally, considerable attention is paid to the pattern of valence results across
studies. It is noted that effects most often lie with biases in the processing of positive
information and that future studies may benefit from a concentration on this aspect of
depressogenic bias utilizing a developmental perspective. Several key theoretical and practical
implications are carefully discussed.
2006-01-01T00:00:00ZDrummond, Lyndsey ElizabethFew studies have examined depression in children from an Information Processing (IP)
perspective. In this thesis a number of domains of IP (known to be associated with adult
depression)are examined in children and adolescents, in particular, autobiographical memory
specificity in both clinical and non-clinical samples. Foremost, overgeneral memory (OGM)
was found for the first time, to be characteristic of dysphoric (Study 1) and clinically
depressed children (Study 2). Similarity in the extent of the OGM bias in depressed and
dysphoric children was observed. OGM was also comparable across child, adolescent and
adult depressed groups (Study 2). Second, OGM predicted depressive symptoms in children
during a stressful life event, in the first longitudinal diathesis-stress investigation of OGM to
date (Study 3). OGM was also linked for the first time to an overgeneral thinking style and to
a depressive attributional style (Study 3) thereby offering possible mechanistic insight in
OGM. Third, in support of Williams' (1996) developmental origins hypothesis, OGM was
also demonstrated in children in residential care who had suffered significant independently
verified negative life events (Study 5). OGM in these youth was positively correlated with
deficits in social problem solving and facial-affect identification, in part contextualizing OGM
in children alongside depresso-typical biases. Performance on the AMT also varied as a
function of severity of abuse with more abused children demonstrating less OGM -a recency
memorial coping strategy is proposed to account for this effect. Fourth, a new measure of EF
was introduced and highlights the importance of encoding preferences in explaining 0GM
(Studies I& 5). Finally, considerable attention is paid to the pattern of valence results across
studies. It is noted that effects most often lie with biases in the processing of positive
information and that future studies may benefit from a concentration on this aspect of
depressogenic bias utilizing a developmental perspective. Several key theoretical and practical
implications are carefully discussed.The psychology of sharing: an evolutionary approachErdal, David Edwardhttps://hdl.handle.net/10023/26562019-07-01T10:04:51Z2000-01-01T00:00:00ZThis thesis takes an evolutionary perspective on human psychology. To
the extent that inherited tendencies shape behaviour, their design will be
fitted to the social environments prevailing as Homo sapiens evolved, in
foraging groups, the nearest modem equivalent being hunter-gatherers.
From ethnographies of hunter-gatherers, food-sharing and counterdominance
were identified as universal. Food-sharing was more thorough
than is explicable purely by kinship or reciprocation; one functional effect
was to even out the supply of valuable high-variance food. In contrast with
the social systems of the other great apes, counter-dominance spread
influence widely, preventing the emergence of dominant individuals who
could obtain resources disproportionately. Potential paths for the evolution of
egalitarian tendencies are discussed.
Two falsifiable hypotheses were generated from this perspective. First,
sharing will facilitate risk-taking. The predicted effect was confirmed at high
risk levels, similar to those faced by hunters. Given that during evolution risk
was reduced primarily by social means, social as well as rational factors are
treated by the evolved brain as relevant to risky decisions. It is argued that
this result may suggest a new perspective on the Group Polarisation
experiments.
The second hypothesis tested was that an egalitarian environment will
produce beneficial effects on individual and social behaviour. The data
collected were consistent with the hypothesis: a comparison between three
Italian towns showed that measures of health (including cardiovascular
mortality), education, social involvement, crime and social perceptions were
significantly more positive where co-operatives employed a larger percentage
of the population.
The evolutionary perspective showed its value as a means of generating
novel testable hypotheses.
2000-01-01T00:00:00ZErdal, David EdwardThis thesis takes an evolutionary perspective on human psychology. To
the extent that inherited tendencies shape behaviour, their design will be
fitted to the social environments prevailing as Homo sapiens evolved, in
foraging groups, the nearest modem equivalent being hunter-gatherers.
From ethnographies of hunter-gatherers, food-sharing and counterdominance
were identified as universal. Food-sharing was more thorough
than is explicable purely by kinship or reciprocation; one functional effect
was to even out the supply of valuable high-variance food. In contrast with
the social systems of the other great apes, counter-dominance spread
influence widely, preventing the emergence of dominant individuals who
could obtain resources disproportionately. Potential paths for the evolution of
egalitarian tendencies are discussed.
Two falsifiable hypotheses were generated from this perspective. First,
sharing will facilitate risk-taking. The predicted effect was confirmed at high
risk levels, similar to those faced by hunters. Given that during evolution risk
was reduced primarily by social means, social as well as rational factors are
treated by the evolved brain as relevant to risky decisions. It is argued that
this result may suggest a new perspective on the Group Polarisation
experiments.
The second hypothesis tested was that an egalitarian environment will
produce beneficial effects on individual and social behaviour. The data
collected were consistent with the hypothesis: a comparison between three
Italian towns showed that measures of health (including cardiovascular
mortality), education, social involvement, crime and social perceptions were
significantly more positive where co-operatives employed a larger percentage
of the population.
The evolutionary perspective showed its value as a means of generating
novel testable hypotheses.Depression : cognitive, social, environmental and emotional factorsHolttum, Susanhttps://hdl.handle.net/10023/26542019-04-01T10:40:44Z1991-01-01T00:00:00ZThis work examined four issues, in relation to both the
experience of depression, and vulnerability to depression.
There were four empirical studies, each with two parts. The
first study examined the role of cognitions, such as
overgeneralizations (Beck, 1963; Beck et al, 1979), and
causal attributions (Abramson et al, 1978; Alloy et al, 1988).
Their role as symptoms of depression, and as possible
vulnerability factors, independent of current mood, was
examined. In the first part of the study, clinically
depressed patients, recovered subjects, and community control
subjects were interviewed and given questionnaires. In the
second part of the study a larger sample of students, some
of whom became mildly depressed on beginning university
filled in questionnaires at the start of term and again five
weeks later. The same subject groups were the basis for the
study on social factors, and the study on life events. The
fourth study was also in two parts. A different sample of
students were the subjects for the first part, and the same
clinical and control groups participated in the second part.
Factors found to be associated with the state of depression
were: Internal, stable and global attributions for the
causes of bad events, negative view of future outcomes, and
negative view of self; social skill deficits and lack of
social support; recent difficult life events. One factor
failed to show any strong association with the depressed state –
unrealistic goals. Factors associated with vulnerability to depression:
Negative evaluations of future outcomes, and of self, unrealistic goals
and, surprisingly, lower-than-normal goals; deficits in social skill
(especially low self-confidence in social settings) and lack
of social support; history-of difficult life events. Factors
which failed to show association with vulnerability to
depression: Causal-attributions for events; adverse reaction
to depression itself. Deficits in social skill were
associated with lack of social support. Depression proneness itself appeared to be a risk factor for negative life events.
1991-01-01T00:00:00ZHolttum, SusanThis work examined four issues, in relation to both the
experience of depression, and vulnerability to depression.
There were four empirical studies, each with two parts. The
first study examined the role of cognitions, such as
overgeneralizations (Beck, 1963; Beck et al, 1979), and
causal attributions (Abramson et al, 1978; Alloy et al, 1988).
Their role as symptoms of depression, and as possible
vulnerability factors, independent of current mood, was
examined. In the first part of the study, clinically
depressed patients, recovered subjects, and community control
subjects were interviewed and given questionnaires. In the
second part of the study a larger sample of students, some
of whom became mildly depressed on beginning university
filled in questionnaires at the start of term and again five
weeks later. The same subject groups were the basis for the
study on social factors, and the study on life events. The
fourth study was also in two parts. A different sample of
students were the subjects for the first part, and the same
clinical and control groups participated in the second part.
Factors found to be associated with the state of depression
were: Internal, stable and global attributions for the
causes of bad events, negative view of future outcomes, and
negative view of self; social skill deficits and lack of
social support; recent difficult life events. One factor
failed to show any strong association with the depressed state –
unrealistic goals. Factors associated with vulnerability to depression:
Negative evaluations of future outcomes, and of self, unrealistic goals
and, surprisingly, lower-than-normal goals; deficits in social skill
(especially low self-confidence in social settings) and lack
of social support; history-of difficult life events. Factors
which failed to show association with vulnerability to
depression: Causal-attributions for events; adverse reaction
to depression itself. Deficits in social skill were
associated with lack of social support. Depression proneness itself appeared to be a risk factor for negative life events.Skills used in food processing by vervet monkeys, Cecropithecus aethiopsHarrison, Kathrynhttps://hdl.handle.net/10023/26362019-04-01T10:40:49Z1997-01-01T00:00:00ZThe principle objective of this study was to describe and record all the gathering
and processing skills of vervet monkeys for a variety of different foods. The study
was conducted on two troops of vervet monkeys living in the Palmiet Valley,
Natal, South Africa. There was sufficient data to analyze the processing of four
foods of differing complexity; termites, leaf shoots, sugarcane and fruit.
Milton (1988) proposed that the intellectual difficulties of finding and processing
food led to the evolution of intelligence. In the only study of food processing skill,
Byrne and Byrne (1993) showed that gorillas use a hierarchical organization
perhaps reflecting imitation at the program-level. The question to be asked in this
study was, would vervets also organize their processing into a few techniques for
specific foods and would it then be possible to identify learning mechanisms used
by the monkeys? The current literature suggests that monkeys use simple solutions
to their foraging problems, there is no evidence for imitation of feeding skills in
monkeys.
At the most detailed level of analysis, grip types used in the processing of foods
were described. Existing definitions in the literature were not adequate to explain
the monkeys' hand use, and new definitions were added. High individual
idiosyncrasy was a feature of grip usage across all four foods, although firm
conclusions are not possible because of the known effects of sample size. Cluster
analysis was considered the most appropriate method to look at individual
variation in grip usage. There was an age effect for leaf shoots and sugarcane,
with juveniles restricting their usage to the necessary core grips.
The hand preferences for individuals across tasks gave no support for the theory of
the evolution of laterality presented by MacNeilage et al. (1987). There was a low
degree of individual preference for five out of six tasks, with only termite feeding
showing a hand preference. There was some evidence for a right hand reaching,
left hand manipulation preference, opposite to MacNeilage's prediction. There was
an age effect in direction and strength for two tasks, adults having a stronger left
hand preference in contrast to a weaker right hand preference in juveniles for leaf
shoots and large fruit.
Matrices of the transitional probabilities between two elements, were used to
construct the common pathways of processing skill for each individual. Flow
diagrams were then created to represent the minimal decision processes used by
the monkeys. The diagrams were used to compare individuals' choice of pathways.
Cluster analysis was used to analyze pathway choice in detail; none of a variety of
independent variables could explain the high individual variation. Whether whole
foods or just parts of foods were eaten did explain some of the variance for
sugarcane and fruit. The most parsimonious explanation is that social enhancement
resulting in trial and error learning best described individuals' acquisition of
processing skill, although a number of other factors may explain the observed
results.
1997-01-01T00:00:00ZHarrison, KathrynThe principle objective of this study was to describe and record all the gathering
and processing skills of vervet monkeys for a variety of different foods. The study
was conducted on two troops of vervet monkeys living in the Palmiet Valley,
Natal, South Africa. There was sufficient data to analyze the processing of four
foods of differing complexity; termites, leaf shoots, sugarcane and fruit.
Milton (1988) proposed that the intellectual difficulties of finding and processing
food led to the evolution of intelligence. In the only study of food processing skill,
Byrne and Byrne (1993) showed that gorillas use a hierarchical organization
perhaps reflecting imitation at the program-level. The question to be asked in this
study was, would vervets also organize their processing into a few techniques for
specific foods and would it then be possible to identify learning mechanisms used
by the monkeys? The current literature suggests that monkeys use simple solutions
to their foraging problems, there is no evidence for imitation of feeding skills in
monkeys.
At the most detailed level of analysis, grip types used in the processing of foods
were described. Existing definitions in the literature were not adequate to explain
the monkeys' hand use, and new definitions were added. High individual
idiosyncrasy was a feature of grip usage across all four foods, although firm
conclusions are not possible because of the known effects of sample size. Cluster
analysis was considered the most appropriate method to look at individual
variation in grip usage. There was an age effect for leaf shoots and sugarcane,
with juveniles restricting their usage to the necessary core grips.
The hand preferences for individuals across tasks gave no support for the theory of
the evolution of laterality presented by MacNeilage et al. (1987). There was a low
degree of individual preference for five out of six tasks, with only termite feeding
showing a hand preference. There was some evidence for a right hand reaching,
left hand manipulation preference, opposite to MacNeilage's prediction. There was
an age effect in direction and strength for two tasks, adults having a stronger left
hand preference in contrast to a weaker right hand preference in juveniles for leaf
shoots and large fruit.
Matrices of the transitional probabilities between two elements, were used to
construct the common pathways of processing skill for each individual. Flow
diagrams were then created to represent the minimal decision processes used by
the monkeys. The diagrams were used to compare individuals' choice of pathways.
Cluster analysis was used to analyze pathway choice in detail; none of a variety of
independent variables could explain the high individual variation. Whether whole
foods or just parts of foods were eaten did explain some of the variance for
sugarcane and fruit. The most parsimonious explanation is that social enhancement
resulting in trial and error learning best described individuals' acquisition of
processing skill, although a number of other factors may explain the observed
results.Anti-predator behaviour of black-fronted titi monkeys (Callicebus nigrifrons)Cäsar, Cristianehttps://hdl.handle.net/10023/25752019-04-01T10:41:11Z2012-06-01T00:00:00ZTiti monkeys have long been known for their complex vocal behaviour with numerous high- and low-pitched calls, which can be uttered singly or combined in more complex structures. However, up to date very little is known concerning the function, meaning and context-specific use of these vocal utterances, and virtually nothing is known about their vocalisations in the predation context.
This thesis presents a detailed description of the form and function of the anti-predator behaviour of one species of titi monkeys, the black-fronted titi monkey (Callicebus nigrifrons), with a specific focus on their alarm call behaviour. A second aim was to determine the exact mechanisms of alarm calling behaviour, with an emphasis on production and comprehension. Data were collected from several habituated groups in the Caraça Reserve, Minas Gerais, Brazil.
Results showed that, when detecting predator species, C nigrifrons produce sequences that initially contain two types of brief, high-pitched calls with distinct frequency contours. Further evidence suggested that some of these sequences are meaningful to conspecific receivers, by indicating the general predator class and location of threat. There were also indications that, within the terrestrial threats, additional information may be encoded by acoustic and compositional differences. Analyses of call order and number of calls per sequence suggested that callers may be able to convey information on both predator type and location.
The black-fronted titi monkeys’ vocal system thus provides a further example of zoo-syntax, in which acoustically fixed units of a vocal repertoire are combined into higher order sequences that are meaningful to recipients. According to current definitions, this type of calling behaviour qualifies as functionally referential, by indicating general predator class, terrestrial predator type and location. As such, this is the first empirical demonstration of a sequence-based alarm call system that conveys information on both predator category and location.
2012-06-01T00:00:00ZCäsar, CristianeTiti monkeys have long been known for their complex vocal behaviour with numerous high- and low-pitched calls, which can be uttered singly or combined in more complex structures. However, up to date very little is known concerning the function, meaning and context-specific use of these vocal utterances, and virtually nothing is known about their vocalisations in the predation context.
This thesis presents a detailed description of the form and function of the anti-predator behaviour of one species of titi monkeys, the black-fronted titi monkey (Callicebus nigrifrons), with a specific focus on their alarm call behaviour. A second aim was to determine the exact mechanisms of alarm calling behaviour, with an emphasis on production and comprehension. Data were collected from several habituated groups in the Caraça Reserve, Minas Gerais, Brazil.
Results showed that, when detecting predator species, C nigrifrons produce sequences that initially contain two types of brief, high-pitched calls with distinct frequency contours. Further evidence suggested that some of these sequences are meaningful to conspecific receivers, by indicating the general predator class and location of threat. There were also indications that, within the terrestrial threats, additional information may be encoded by acoustic and compositional differences. Analyses of call order and number of calls per sequence suggested that callers may be able to convey information on both predator type and location.
The black-fronted titi monkeys’ vocal system thus provides a further example of zoo-syntax, in which acoustically fixed units of a vocal repertoire are combined into higher order sequences that are meaningful to recipients. According to current definitions, this type of calling behaviour qualifies as functionally referential, by indicating general predator class, terrestrial predator type and location. As such, this is the first empirical demonstration of a sequence-based alarm call system that conveys information on both predator category and location.Evidence for weak or linear conformity but not for hyper-conformity in an everyday social learning contextClaidiere, NicolasBowler, Mark TimothyWhiten, Andrewhttps://hdl.handle.net/10023/25552023-04-18T09:44:58Z2012-02-20T00:00:00ZConformity is thought to be an important force in cultural evolution because it has the potential to stabilize cooperation in large groups, potentiate group selection and thus explain uniquely human behaviors. However, the effects of such conformity on cultural and biological evolution will depend much on the way individuals are influenced by the frequency of alternative behavioral options witnessed. Theoretical modeling has suggested that only what we refer to as ‘hyper-conformity’, an exaggerated tendency to perform the most frequent behavior witnessed in other individuals, is able to increase within-group homogeneity and between-group diversity, for instance. Empirically however, few experiments have addressed how the frequency of behavior witnessed affects behavior. Accordingly we performed an experiment to test for the presence of conformity in a natural situation with humans. Visitors to a Zoo exhibit were invited to write or draw answers to questions on A5 cards and potentially win a small prize. We manipulated the proportion of existing writings versus drawings visible to visitors and measured the proportion of written cards submitted. We found a strong and significant effect of the proportion of text displayed on the proportion of text in the answers, thus demonstrating social learning. We show that this effect is approximately linear, with potentially a small, weak-conformist component but no hyper-conformist one. The present experiment therefore provides evidence for linear conformity in humans in a very natural context.
2012-02-20T00:00:00ZClaidiere, NicolasBowler, Mark TimothyWhiten, AndrewConformity is thought to be an important force in cultural evolution because it has the potential to stabilize cooperation in large groups, potentiate group selection and thus explain uniquely human behaviors. However, the effects of such conformity on cultural and biological evolution will depend much on the way individuals are influenced by the frequency of alternative behavioral options witnessed. Theoretical modeling has suggested that only what we refer to as ‘hyper-conformity’, an exaggerated tendency to perform the most frequent behavior witnessed in other individuals, is able to increase within-group homogeneity and between-group diversity, for instance. Empirically however, few experiments have addressed how the frequency of behavior witnessed affects behavior. Accordingly we performed an experiment to test for the presence of conformity in a natural situation with humans. Visitors to a Zoo exhibit were invited to write or draw answers to questions on A5 cards and potentially win a small prize. We manipulated the proportion of existing writings versus drawings visible to visitors and measured the proportion of written cards submitted. We found a strong and significant effect of the proportion of text displayed on the proportion of text in the answers, thus demonstrating social learning. We show that this effect is approximately linear, with potentially a small, weak-conformist component but no hyper-conformist one. The present experiment therefore provides evidence for linear conformity in humans in a very natural context.Developmental and sex differences in responses to novel objects : an exploration of animal models of sensation seeking behaviourCyrenne, De-Lainehttps://hdl.handle.net/10023/25502019-07-01T10:13:42Z2012-06-19T00:00:00ZHuman adolescents exhibit higher levels of sensation seeking behaviour than younger or older individuals, and sensation seeking is higher in males than females from adolescence onwards. Data suggest that changes in gonadal hormone levels during adolescence and differences in the dopamine neurotransmitter system are the bases for why some people exhibit sensation seeking behaviour while others do not. However, causal relationships between physiology and behaviour have been difficult to establish in humans. In order to explore the physiological influences on novelty-seeking behaviour, we looked at response to novelty in a laboratory rodent. This research examined responses to novelty in the conditioned place preference (CPP) task and the novel object recognition (NOR) task in Lister-hooded rats, and assessed the benefits and limitations of each methodology. While the CPP task was not found to provide a reliable measure of response to novelty, the NOR task was more successful. In order to understand the ontogeny of sex differences in novelty responses, both males and females were tested from adolescence through to adulthood. While no sex difference was found in adults in the NOR test, mid-adolescent males exhibited higher novelty preference behaviour than either younger or older males, or females at each stage of development. Since gonadal hormones levels rise during adolescence, a pharmacological agent (a gonadotrophin-releasing hormone antagonist) was used to suppress gonadal hormone levels from early adolescence before again examining responses on the NOR test at mid-adolescence. Gonadal hormone suppression from early adolescence onwards eliminated the sex difference in the NOR test at mid-adolescence by reducing the male response to novelty, while no difference was measured in the female animals. These findings suggest that gonadal hormones play a significant role in the development of response to novelty, especially in males, and the implications for our understanding of human sensation-seeking behaviour are discussed.
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2012-06-19T00:00:00ZCyrenne, De-LaineHuman adolescents exhibit higher levels of sensation seeking behaviour than younger or older individuals, and sensation seeking is higher in males than females from adolescence onwards. Data suggest that changes in gonadal hormone levels during adolescence and differences in the dopamine neurotransmitter system are the bases for why some people exhibit sensation seeking behaviour while others do not. However, causal relationships between physiology and behaviour have been difficult to establish in humans. In order to explore the physiological influences on novelty-seeking behaviour, we looked at response to novelty in a laboratory rodent. This research examined responses to novelty in the conditioned place preference (CPP) task and the novel object recognition (NOR) task in Lister-hooded rats, and assessed the benefits and limitations of each methodology. While the CPP task was not found to provide a reliable measure of response to novelty, the NOR task was more successful. In order to understand the ontogeny of sex differences in novelty responses, both males and females were tested from adolescence through to adulthood. While no sex difference was found in adults in the NOR test, mid-adolescent males exhibited higher novelty preference behaviour than either younger or older males, or females at each stage of development. Since gonadal hormones levels rise during adolescence, a pharmacological agent (a gonadotrophin-releasing hormone antagonist) was used to suppress gonadal hormone levels from early adolescence before again examining responses on the NOR test at mid-adolescence. Gonadal hormone suppression from early adolescence onwards eliminated the sex difference in the NOR test at mid-adolescence by reducing the male response to novelty, while no difference was measured in the female animals. These findings suggest that gonadal hormones play a significant role in the development of response to novelty, especially in males, and the implications for our understanding of human sensation-seeking behaviour are discussed.Gestural communication in wild chimpanzeesHobaiter, Catherinehttps://hdl.handle.net/10023/21432019-07-01T10:04:55Z2012-06-21T00:00:00ZGreat ape gesture is an elaborate, flexible system of intentional communication. It has been suggested that human language originated in gesture, thus, the gestural communication of great apes is of great interest for questions on the origin of language. To date, systematic studies of great ape gesture have been limited to restricted captive settings, supplemented by the study of a few specific gestures in wild populations. To address questions about gestural communication from an evolutionary perspective it is necessary to extend the systematic study of gesture into a wild ape population. I therefore undertook a 22-month study of gesture in the wild Sonso chimpanzee community in Budongo, Uganda.
Sonso chimpanzees employ a large repertoire of species-typical gestures in intentional communication; a proportion of this repertoire appears to be ape-typical, as would be expected with a biologically given trait. Chimpanzees can acquire new behavioural patterns through imitation; however, this apparently does not represent a significant means of acquiring gestures. Gesturing was employed regularly in an intentional manner from the end of the first year, and was used by chimpanzees of all ages to communicate across a range of contexts, including the evolutionarily urgent context of consortship. Immature chimpanzees used a wide range of gestures, which they combined into rapid sequences. With maturity, use of the repertoire was ‘tuned’ to focus on the most effective gestures, which were then used individually. Despite the evidence for referential pointing in captive chimpanzees, there was little evidence for the regular use of it in wild chimpanzees. Gestures were used to communicate a range of imperative requests that regulated social behaviour. Chimpanzee gestures vary from the ambiguous to the highly specific in meaning; and, while gestures were used flexibly, they tended to be associated with a single dominant meaning.
2012-06-21T00:00:00ZHobaiter, CatherineGreat ape gesture is an elaborate, flexible system of intentional communication. It has been suggested that human language originated in gesture, thus, the gestural communication of great apes is of great interest for questions on the origin of language. To date, systematic studies of great ape gesture have been limited to restricted captive settings, supplemented by the study of a few specific gestures in wild populations. To address questions about gestural communication from an evolutionary perspective it is necessary to extend the systematic study of gesture into a wild ape population. I therefore undertook a 22-month study of gesture in the wild Sonso chimpanzee community in Budongo, Uganda.
Sonso chimpanzees employ a large repertoire of species-typical gestures in intentional communication; a proportion of this repertoire appears to be ape-typical, as would be expected with a biologically given trait. Chimpanzees can acquire new behavioural patterns through imitation; however, this apparently does not represent a significant means of acquiring gestures. Gesturing was employed regularly in an intentional manner from the end of the first year, and was used by chimpanzees of all ages to communicate across a range of contexts, including the evolutionarily urgent context of consortship. Immature chimpanzees used a wide range of gestures, which they combined into rapid sequences. With maturity, use of the repertoire was ‘tuned’ to focus on the most effective gestures, which were then used individually. Despite the evidence for referential pointing in captive chimpanzees, there was little evidence for the regular use of it in wild chimpanzees. Gestures were used to communicate a range of imperative requests that regulated social behaviour. Chimpanzee gestures vary from the ambiguous to the highly specific in meaning; and, while gestures were used flexibly, they tended to be associated with a single dominant meaning.Pant-grunts in wild chimpanzees (Pan troglodytes schweinfurthii): the vocal development of a social signalLaporte, Marion N.C.https://hdl.handle.net/10023/19732019-07-01T10:18:57Z2011-06-21T00:00:00ZWhile the gestural communication of apes is widely recognised as intentional and flexible, their vocal communication still remains considered as mostly genetically determined and emotionally bound. Trying to limit the direct projections of linguistic concepts, that are far from holding a unified view on what constitute human language, this thesis presents a detailed
description of the pant-grunt vocalisation usage and development in the chimpanzees (Pan
troglodytes schweinfurthii) of the Budongo forest, Uganda.
Pant-grunts are one of the most social vocalisations of the chimpanzee vocal repertoire and are always given from a subordinate individual to a dominant. The question of how such a signal is used and develops is critical for our understanding of chimpanzee social and vocal complexity in an ontogenetical and phylogenetical perpective. Results suggest that pant-grunt
vocalisations can be used in a flexible way, both in their form and usage within a social group.
More specifically, chimpanzees seemed to take into account the number and identity of
surrounding individuals before producing these vocalisations. At the acoustic level, pant-grunts seem to be very variable vocalisations that corresponded to different social situations commonly encountered. Grunts are one of the first vocalisations produced by babies but they are not first produced in social contexts. Although some modifications of the social grunts
form and usage could not entirely be attributed to maturation only, the role of the mother seemed to be restricted. Her direct influence was perhaps more visible in the rhythmic patterns of chorusing events. Taken together, this thesis suggests that chimpanzee vocalisations are more flexible in their usage, production and acquisition than previously thought and might therefore be more similar to gestural communication.
2011-06-21T00:00:00ZLaporte, Marion N.C.While the gestural communication of apes is widely recognised as intentional and flexible, their vocal communication still remains considered as mostly genetically determined and emotionally bound. Trying to limit the direct projections of linguistic concepts, that are far from holding a unified view on what constitute human language, this thesis presents a detailed
description of the pant-grunt vocalisation usage and development in the chimpanzees (Pan
troglodytes schweinfurthii) of the Budongo forest, Uganda.
Pant-grunts are one of the most social vocalisations of the chimpanzee vocal repertoire and are always given from a subordinate individual to a dominant. The question of how such a signal is used and develops is critical for our understanding of chimpanzee social and vocal complexity in an ontogenetical and phylogenetical perpective. Results suggest that pant-grunt
vocalisations can be used in a flexible way, both in their form and usage within a social group.
More specifically, chimpanzees seemed to take into account the number and identity of
surrounding individuals before producing these vocalisations. At the acoustic level, pant-grunts seem to be very variable vocalisations that corresponded to different social situations commonly encountered. Grunts are one of the first vocalisations produced by babies but they are not first produced in social contexts. Although some modifications of the social grunts
form and usage could not entirely be attributed to maturation only, the role of the mother seemed to be restricted. Her direct influence was perhaps more visible in the rhythmic patterns of chorusing events. Taken together, this thesis suggests that chimpanzee vocalisations are more flexible in their usage, production and acquisition than previously thought and might therefore be more similar to gestural communication.Binocular vision and three-dimensional motion perception : the use of changing disparity and inter-ocular velocity differencesGrafton, Catherine E.https://hdl.handle.net/10023/19222019-07-01T10:19:46Z2011-06-22T00:00:00ZThis thesis investigates the use of binocular information for motion-in-depth (MID) perception. There are at least two different types of binocular information available to the visual system from which to derive a perception of MID: changing disparity (CD) and inter-ocular velocity differences (IOVD). In the following experiments, we manipulate the availability of CD and IOVD information in order to assess the relative influence of each on MID judgements.
In the first experiment, we assessed the relative effectiveness of CD and IOVD information for MID detection, and whether the two types of binocular information are processed by separate mechanisms with differing characteristics. Our results suggest that, both CD and IOVD information can be utilised for MID detection, yet, the relative dependence on either of these types of MID information varies between observers.
We then went on to explore the contribution of CD and IOVD information to time-to-contact (TTC) perception, whereby an observer judges the time at which an approaching stimulus will contact them. We confirmed that the addition of congruent binocular information to looming stimuli can influence TTC judgements, but that there is no influence from binocular information indicating no motion. Further to this, we found that observers could utilise both CD and IOVD for TTC judgements, although once again, individual receptiveness to CD and/or IOVD information varied.
Thus, we demonstrate that the human visual system is able to process both CD and IOVD information, but the influence of either (or both) of these cues on an individual’s perception has been shown to be mutually independent.
2011-06-22T00:00:00ZGrafton, Catherine E.This thesis investigates the use of binocular information for motion-in-depth (MID) perception. There are at least two different types of binocular information available to the visual system from which to derive a perception of MID: changing disparity (CD) and inter-ocular velocity differences (IOVD). In the following experiments, we manipulate the availability of CD and IOVD information in order to assess the relative influence of each on MID judgements.
In the first experiment, we assessed the relative effectiveness of CD and IOVD information for MID detection, and whether the two types of binocular information are processed by separate mechanisms with differing characteristics. Our results suggest that, both CD and IOVD information can be utilised for MID detection, yet, the relative dependence on either of these types of MID information varies between observers.
We then went on to explore the contribution of CD and IOVD information to time-to-contact (TTC) perception, whereby an observer judges the time at which an approaching stimulus will contact them. We confirmed that the addition of congruent binocular information to looming stimuli can influence TTC judgements, but that there is no influence from binocular information indicating no motion. Further to this, we found that observers could utilise both CD and IOVD for TTC judgements, although once again, individual receptiveness to CD and/or IOVD information varied.
Thus, we demonstrate that the human visual system is able to process both CD and IOVD information, but the influence of either (or both) of these cues on an individual’s perception has been shown to be mutually independent.Attention following and nonverbal referential communication in bonobos (Pan paniscus), chimpanzees (Pan troglodytes) and orangutans (Pongo pygmaeus)Madsen, Elainie Alenkærhttps://hdl.handle.net/10023/18932019-07-01T10:09:02Z2011-06-22T00:00:00ZA central issue in the study of primate communication is the extent to which individuals adjust their behaviour to the attention and signals of others, and manipulate others’ attention to communicate about external events. I investigated whether 13 chimpanzees (Pan troglodytes spp.), 11 bonobos (Pan paniscus), and 7 orangutans (Pongo pygmaeus pygmaeus) followed conspecific attention and led others to distal locations. Individuals were presented with a novel stimulus, to test if they would lead a conspecific to detect it in two experimental conditions. In one the conspecific faced the communicator, while another required the communicator to first attract the attention of a conspecific. All species followed conspecific attention, but only bonobos in conditions that required geometric attention following and that the communicator first attract the conspecific‘s attention. There was a clear trend for the chimpanzees to selectively produce a stimulus directional ‘hunching’ posture when viewing the stimulus in the presence of a conspecific rather than alone (the comparison was statistically non-significant, but very closely approached significance [p = 0.056]), and the behaviour consistently led conspecifics to look towards the stimulus. An observational study showed that ‘hunching’ only occurred in the context of attention following. Some chimpanzees and bonobos consistently and selectively combined functionally different behaviours (consisting of sequential auditory-stimulus-directional-behaviours), when viewing the stimulus in the presence of a non-attentive conspecific, although at species level this did not yield significant effects. While the design did not eliminate the possibility of a social referencing motive (“look and help me decide how to respond”), the coupling of auditory cues followed by directional cues towards a novel object, is consistent with a declarative and social referential interpretation of non-verbal deixis. An exploratory study, which applied the ‘Social Attention Hypothesis’ (that individuals accord and receive attention as a function of dominance) to attention following, showed that chimpanzees were more likely to follow the attention of the dominant individual. Overall, the results suggest that the paucity of observed referential behaviours in apes may owe to the inconspicuousness and multi-faceted nature of the behaviours.
2011-06-22T00:00:00ZMadsen, Elainie AlenkærA central issue in the study of primate communication is the extent to which individuals adjust their behaviour to the attention and signals of others, and manipulate others’ attention to communicate about external events. I investigated whether 13 chimpanzees (Pan troglodytes spp.), 11 bonobos (Pan paniscus), and 7 orangutans (Pongo pygmaeus pygmaeus) followed conspecific attention and led others to distal locations. Individuals were presented with a novel stimulus, to test if they would lead a conspecific to detect it in two experimental conditions. In one the conspecific faced the communicator, while another required the communicator to first attract the attention of a conspecific. All species followed conspecific attention, but only bonobos in conditions that required geometric attention following and that the communicator first attract the conspecific‘s attention. There was a clear trend for the chimpanzees to selectively produce a stimulus directional ‘hunching’ posture when viewing the stimulus in the presence of a conspecific rather than alone (the comparison was statistically non-significant, but very closely approached significance [p = 0.056]), and the behaviour consistently led conspecifics to look towards the stimulus. An observational study showed that ‘hunching’ only occurred in the context of attention following. Some chimpanzees and bonobos consistently and selectively combined functionally different behaviours (consisting of sequential auditory-stimulus-directional-behaviours), when viewing the stimulus in the presence of a non-attentive conspecific, although at species level this did not yield significant effects. While the design did not eliminate the possibility of a social referencing motive (“look and help me decide how to respond”), the coupling of auditory cues followed by directional cues towards a novel object, is consistent with a declarative and social referential interpretation of non-verbal deixis. An exploratory study, which applied the ‘Social Attention Hypothesis’ (that individuals accord and receive attention as a function of dominance) to attention following, showed that chimpanzees were more likely to follow the attention of the dominant individual. Overall, the results suggest that the paucity of observed referential behaviours in apes may owe to the inconspicuousness and multi-faceted nature of the behaviours.Vocal communication in bonobos (Pan paniscus) : studies in the contexts of feeding and sexClay, Zannahttps://hdl.handle.net/10023/18422019-04-01T10:41:01Z2011-06-01T00:00:00ZDespite having being discovered nearly 80 years ago, bonobos (Pan paniscus) are still one of the least well understood of the great apes, largely remaining in the shadow of their better known cousins, the chimpanzees (Pan troglodytes). This is especially evident in the domain of communication, with bonobo vocal behaviour still a
neglected field of study, especially compared to that of chimpanzees. In this thesis, I address this issue by exploring the natural vocal communication of bonobos and its underlying cognition, focusing on the role that vocalisations play during two key contexts, food discovery and sex. In the context of food-discovery, I combine
observational and experimental techniques to examine whether bonobos produce and understand vocalisations that convey meaningful information about the quality of
food encountered by the caller. Results indicate that bonobos produce an array of vocalisations when finding food, and combine different food-associated calls together into sequences in a way that relates to perceived food quality. In a subsequent playback study, it was demonstrated that receivers are able to extract meaning about perceived food quality by attending to these calls and integrating information across call sequences. In the context of sexual interactions, I examine the acoustic structure of female copulation calls, as well as patterns in call usage, to explore how these signals are used by individuals. My results show that females emit copulation calls in similar ways with both male and female partners, suggesting that these signals have become partly divorced from a function in reproduction, to assume a greater social role. Overall, my results highlight the relevance of studying primate vocalisations to investigate the underlying cognition and suggest that vocalisations are important behavioural tools for bonobos to navigate their social and physical worlds.
2011-06-01T00:00:00ZClay, ZannaDespite having being discovered nearly 80 years ago, bonobos (Pan paniscus) are still one of the least well understood of the great apes, largely remaining in the shadow of their better known cousins, the chimpanzees (Pan troglodytes). This is especially evident in the domain of communication, with bonobo vocal behaviour still a
neglected field of study, especially compared to that of chimpanzees. In this thesis, I address this issue by exploring the natural vocal communication of bonobos and its underlying cognition, focusing on the role that vocalisations play during two key contexts, food discovery and sex. In the context of food-discovery, I combine
observational and experimental techniques to examine whether bonobos produce and understand vocalisations that convey meaningful information about the quality of
food encountered by the caller. Results indicate that bonobos produce an array of vocalisations when finding food, and combine different food-associated calls together into sequences in a way that relates to perceived food quality. In a subsequent playback study, it was demonstrated that receivers are able to extract meaning about perceived food quality by attending to these calls and integrating information across call sequences. In the context of sexual interactions, I examine the acoustic structure of female copulation calls, as well as patterns in call usage, to explore how these signals are used by individuals. My results show that females emit copulation calls in similar ways with both male and female partners, suggesting that these signals have become partly divorced from a function in reproduction, to assume a greater social role. Overall, my results highlight the relevance of studying primate vocalisations to investigate the underlying cognition and suggest that vocalisations are important behavioural tools for bonobos to navigate their social and physical worlds.The vocalisations and anti-predatory behaviour of wild white-handed gibbons (Hylobates lar) in Khao Yai National Park, ThailandClarke, Esther A. E.https://hdl.handle.net/10023/16882019-04-01T10:41:03Z2010-01-01T00:00:00ZThe loud songs of gibbons (Hylobatidae) usually consist of a duet by the mated pair
delivered each morning. These songs can transmit over a kilometre through dense
forest habitat and therefore presumably play a role in long-distance communication.
There is some evidence to suggest that gibbons use song in contexts other than their
daily duets, such as predation, but these songs have not been well studied. Close-
range communication is also relevant for gibbons, but these quieter calls have
completely escaped any detailed observation.
The responses of wild white-handed gibbons (Hylobates lar) to simulated visual and
acoustic predators (tiger, clouded leopard, reticulated python and crested serpent
eagle) were studied in Khao Yai National Park, Thailand to address the lack of
empirical data about these important events. Little is known about gibbons’ anti-
predatory behaviour in general, and simulated predator encounters provided an
opportunity to investigate these responses as well.
Results showed that gibbons used song as part of their anti-predator strategy and that
subtle combinatorial changes were meaningful to conspecifics. They also showed
marked behavioural changes in the short-term, and some evidence of longer-term
changes as well. Quiet calls were also part of the gibbons’ response repertoire with
the hoo call being particularly relevant. Hoos were used as a prelude to singing both
normal duets and predator songs, but there were consistent differences between each
context. Hoos were also delivered independently in a number of other contexts outside predation. When analysed, these hoos showed consistent contextual
differences in a number of spectral parameters.
Within the duet context, important contextual subtleties were evident also revealing a
remarkable vocal plasticity. In addition, gibbons voluntarily attended to specific
vocal elements of other gibbon duets, indicating that certain sequences are more
pertinent than others.
Results suggest both gibbon song and gibbon hoos are powerful communication tools
that reliably reference external objects and events; this ability is also a critical feature
of human language.
2010-01-01T00:00:00ZClarke, Esther A. E.The loud songs of gibbons (Hylobatidae) usually consist of a duet by the mated pair
delivered each morning. These songs can transmit over a kilometre through dense
forest habitat and therefore presumably play a role in long-distance communication.
There is some evidence to suggest that gibbons use song in contexts other than their
daily duets, such as predation, but these songs have not been well studied. Close-
range communication is also relevant for gibbons, but these quieter calls have
completely escaped any detailed observation.
The responses of wild white-handed gibbons (Hylobates lar) to simulated visual and
acoustic predators (tiger, clouded leopard, reticulated python and crested serpent
eagle) were studied in Khao Yai National Park, Thailand to address the lack of
empirical data about these important events. Little is known about gibbons’ anti-
predatory behaviour in general, and simulated predator encounters provided an
opportunity to investigate these responses as well.
Results showed that gibbons used song as part of their anti-predator strategy and that
subtle combinatorial changes were meaningful to conspecifics. They also showed
marked behavioural changes in the short-term, and some evidence of longer-term
changes as well. Quiet calls were also part of the gibbons’ response repertoire with
the hoo call being particularly relevant. Hoos were used as a prelude to singing both
normal duets and predator songs, but there were consistent differences between each
context. Hoos were also delivered independently in a number of other contexts outside predation. When analysed, these hoos showed consistent contextual
differences in a number of spectral parameters.
Within the duet context, important contextual subtleties were evident also revealing a
remarkable vocal plasticity. In addition, gibbons voluntarily attended to specific
vocal elements of other gibbon duets, indicating that certain sequences are more
pertinent than others.
Results suggest both gibbon song and gibbon hoos are powerful communication tools
that reliably reference external objects and events; this ability is also a critical feature
of human language.Sexual selection and trust gamesStirrat, Michaelhttps://hdl.handle.net/10023/10142019-04-01T10:41:34Z2010-06-23T00:00:00ZIn economic games the facial attributes of counterparts bias decisions to trust and decisions to enter play. We report research supporting hypotheses that trust and reciprocation decisions in trust games are biased by mechanisms of sexual selection. Hypotheses that trust game behaviour is modulated by inter-sexual competition were supported. 1) Attractive individuals elicit more cooperation. 2) Male participants display trust and reciprocation toward attractive female counterparts in excess of perceived trustworthiness (and this display is modulated by male self-reported physical dominance). 3) Female participants appear to respond to male trust as a signal of sexual interest and are therefore more likely to exploit the trust of attractive males. 4) In explicitly dating contexts females are more likely to prefer attractive males to pay for the meal. These results indicate that participants are biased by mate choice and mating display considerations while playing economic games in the lab. Hypotheses that trust game behaviour is modulated by intra-sexual competition for resources were also somewhat supported. 1) Male participants reporting an ability to win fights with same-sex peers are more exploitative of other males. 2) Cues to current circulating testosterone level in counterpart’s faces are less trusted but elicit more reciprocation. 3) The male sexually dimorphic trait facial width-to-height ratio (a trait which is related to both aggression and dominance) is related to an increased proportion of decisions to exploit others in the trust game while also being used by others as a cue to untrustworthiness. We conclude that trusting and trustworthy behaviour in both sexes is biased by mating market considerations predicted by intra- and inter-sexual selection.
2010-06-23T00:00:00ZStirrat, MichaelIn economic games the facial attributes of counterparts bias decisions to trust and decisions to enter play. We report research supporting hypotheses that trust and reciprocation decisions in trust games are biased by mechanisms of sexual selection. Hypotheses that trust game behaviour is modulated by inter-sexual competition were supported. 1) Attractive individuals elicit more cooperation. 2) Male participants display trust and reciprocation toward attractive female counterparts in excess of perceived trustworthiness (and this display is modulated by male self-reported physical dominance). 3) Female participants appear to respond to male trust as a signal of sexual interest and are therefore more likely to exploit the trust of attractive males. 4) In explicitly dating contexts females are more likely to prefer attractive males to pay for the meal. These results indicate that participants are biased by mate choice and mating display considerations while playing economic games in the lab. Hypotheses that trust game behaviour is modulated by intra-sexual competition for resources were also somewhat supported. 1) Male participants reporting an ability to win fights with same-sex peers are more exploitative of other males. 2) Cues to current circulating testosterone level in counterpart’s faces are less trusted but elicit more reciprocation. 3) The male sexually dimorphic trait facial width-to-height ratio (a trait which is related to both aggression and dominance) is related to an increased proportion of decisions to exploit others in the trust game while also being used by others as a cue to untrustworthiness. We conclude that trusting and trustworthy behaviour in both sexes is biased by mating market considerations predicted by intra- and inter-sexual selection.Behavioural phenotyping of mice with genetic alterations of the GABA[subscript A] receptorFoister, Nicolahttps://hdl.handle.net/10023/9882019-07-01T10:12:29Z2010-06-23T00:00:00ZGABA is the main inhibitory neurotransmitter of the central nervous system. GABA[subscript A]Rs are multimeric transmembrane receptors, which are composed of 5 subunits. It is known that there are 19 subunits that can make up the GABA[subscript A]Rs, allowing for a vast array of receptor subtypes. In addition to the GABA binding site GABA[subscript A]Rs have distinct allosteric binding sites for benzodiazepines, barbiturates, ethanol, certain general anaesthetics and neuroactive steroids. The molecular heterogeneity of the GABA[subscript A]R is accompanied by distinct pharmacological profiles of the different receptor subtypes. The advance of transgenic mouse models has allowed the functional significance of this heterogeneity to be studied in vivo. Therefore, this thesis utilises a variety of transgenic mouse models carrying either mutations or deletions of certain subunits to study the functional significance of the receptor heterogeneity.
Mice lacking the α1 subunit (α1[superscript(-/-)]), carrying a point mutation of the α1 subunit (α1H101R), and mice lacking the δ subunit (δ[superscript(-/-)]) have been utilised to investigate the role of these subunits in the sedative actions of benzodiazepines and the GABA[subscript A]R agonist THIP. Although there are limitations to the interpretation of these results due genetic background of the α1[superscript(-/-)] and α1H101R, experiments suggest that the α1H101R mutation is not behaviourally silent as previously suggested and provide further evidence that the α1 subunit mediates the sedative properties of benzodiazepines. These experiments also reveal that the extrasynaptic δ containing receptors are responsible for mediating the sedative effects of THIP, and these findings combined with evidence from collaborators, implicates the thalamus as an anatomical mediator of these effects.
An investigation of the putative cognitive enhancing effects of THIP using an attentional set-shifting task for mice suggested that pre-treatment with THIP reduces the number of errors to reach criterion. δ[superscript(-/-)] mice could not be trained to perform the task, therefore further behavioural investigation of these mice was performed, which suggested a heightened level of anxiety and reduced motivation for a food reward.
This thesis has furthered our understanding of the functional role of GABA[subscript A]R subtypes. With the advance in genetic manipulations that allow for regionally selective mutations of the receptor the anatomical structures involved in these functions can be identified.
2010-06-23T00:00:00ZFoister, NicolaGABA is the main inhibitory neurotransmitter of the central nervous system. GABA[subscript A]Rs are multimeric transmembrane receptors, which are composed of 5 subunits. It is known that there are 19 subunits that can make up the GABA[subscript A]Rs, allowing for a vast array of receptor subtypes. In addition to the GABA binding site GABA[subscript A]Rs have distinct allosteric binding sites for benzodiazepines, barbiturates, ethanol, certain general anaesthetics and neuroactive steroids. The molecular heterogeneity of the GABA[subscript A]R is accompanied by distinct pharmacological profiles of the different receptor subtypes. The advance of transgenic mouse models has allowed the functional significance of this heterogeneity to be studied in vivo. Therefore, this thesis utilises a variety of transgenic mouse models carrying either mutations or deletions of certain subunits to study the functional significance of the receptor heterogeneity.
Mice lacking the α1 subunit (α1[superscript(-/-)]), carrying a point mutation of the α1 subunit (α1H101R), and mice lacking the δ subunit (δ[superscript(-/-)]) have been utilised to investigate the role of these subunits in the sedative actions of benzodiazepines and the GABA[subscript A]R agonist THIP. Although there are limitations to the interpretation of these results due genetic background of the α1[superscript(-/-)] and α1H101R, experiments suggest that the α1H101R mutation is not behaviourally silent as previously suggested and provide further evidence that the α1 subunit mediates the sedative properties of benzodiazepines. These experiments also reveal that the extrasynaptic δ containing receptors are responsible for mediating the sedative effects of THIP, and these findings combined with evidence from collaborators, implicates the thalamus as an anatomical mediator of these effects.
An investigation of the putative cognitive enhancing effects of THIP using an attentional set-shifting task for mice suggested that pre-treatment with THIP reduces the number of errors to reach criterion. δ[superscript(-/-)] mice could not be trained to perform the task, therefore further behavioural investigation of these mice was performed, which suggested a heightened level of anxiety and reduced motivation for a food reward.
This thesis has furthered our understanding of the functional role of GABA[subscript A]R subtypes. With the advance in genetic manipulations that allow for regionally selective mutations of the receptor the anatomical structures involved in these functions can be identified.The maker not the tool: The cognitive significance of great ape manual skillsByrne, RWhttps://hdl.handle.net/10023/9642019-04-01T10:37:45Z2005-01-01T00:00:00ZTool-use by chimpanzees has attracted disproportionate attention among primatologists, because of an understandable wish to understand the evolutionary origins of hominin tool use. In archaeology and paleoanthropology, a focus on made-objects is inevitable: there is nothing else to study. However, it is evidently object-directed manual skills, enabling the objects to be made, that are critical in understanding the evolutionary origins of stone-tool manufacture. In this chapter I review object-directed manual skills in living great apes, making comparison where possible with hominin abilities that can be inferred from the archaeological record. To this end, ‘translations’ of terminology between the research traditions are offered. Much of the evidence comes from observation of apes gathering plants that present physical problems for handling and consumption, in addition to the more patchy data from tool use in captivity and the field. The living great apes, like ourselves, build up novel hierarchical structures involving regular sequences of elementary actions, showing co-ordinated manual role differentiation, in modular organizations with the option of iterating subroutines. Further, great apes appear able to use imitation of skilled practitioners as one source of information for this process, implying some ability to ‘see’ below the surface level of action and understand the motor planning of other individual; however, that process does not necessarily involve understanding cause-and-effect or the intentions of other individuals. Finally I consider whether a living non-human ape could effectively knap stone, and if not, what competence is lacking.
2005-01-01T00:00:00ZByrne, RWTool-use by chimpanzees has attracted disproportionate attention among primatologists, because of an understandable wish to understand the evolutionary origins of hominin tool use. In archaeology and paleoanthropology, a focus on made-objects is inevitable: there is nothing else to study. However, it is evidently object-directed manual skills, enabling the objects to be made, that are critical in understanding the evolutionary origins of stone-tool manufacture. In this chapter I review object-directed manual skills in living great apes, making comparison where possible with hominin abilities that can be inferred from the archaeological record. To this end, ‘translations’ of terminology between the research traditions are offered. Much of the evidence comes from observation of apes gathering plants that present physical problems for handling and consumption, in addition to the more patchy data from tool use in captivity and the field. The living great apes, like ourselves, build up novel hierarchical structures involving regular sequences of elementary actions, showing co-ordinated manual role differentiation, in modular organizations with the option of iterating subroutines. Further, great apes appear able to use imitation of skilled practitioners as one source of information for this process, implying some ability to ‘see’ below the surface level of action and understand the motor planning of other individual; however, that process does not necessarily involve understanding cause-and-effect or the intentions of other individuals. Finally I consider whether a living non-human ape could effectively knap stone, and if not, what competence is lacking.The manual skills and cognition that lie behind hominid tool useByrne, RWhttps://hdl.handle.net/10023/9432020-11-23T15:46:48Z2004-01-01T00:00:00ZTool use is an important aspect of being human that has assumed a central place in accounts of the evolutionary origins of human intelligence. This has inevitably focused a spotlight on any signs of tool use or manufacture in great apes and other non-human animals, to the relative neglect of skills that do not involve tools. The aim of this chapter is to explore whether this emphasis is appropriate. Could it be that we may learn as much about the origin of human intelligence from skilled manual behaviour in general? Suppose we take this broader view, accepting evidence from all manifestations of manual skill, what can we learn of the mental capacities of the great apes and ourselves? My own ultimate purpose is to use comparative evidence from living species to reconstruct the evolutionary history of the many cognitive traits that came together to make human psychology. The cognition of great apes is the obvious starting point, to trace the more primitive (i.e. ancient) cognitive aptitudes that are still important to us today. In this chapter, I focus on great ape cognition as it is expressed in manual skills, based on cognitive aspects of tool use and manufacture considered significant in the human evolutionary lineage.
2004-01-01T00:00:00ZByrne, RWTool use is an important aspect of being human that has assumed a central place in accounts of the evolutionary origins of human intelligence. This has inevitably focused a spotlight on any signs of tool use or manufacture in great apes and other non-human animals, to the relative neglect of skills that do not involve tools. The aim of this chapter is to explore whether this emphasis is appropriate. Could it be that we may learn as much about the origin of human intelligence from skilled manual behaviour in general? Suppose we take this broader view, accepting evidence from all manifestations of manual skill, what can we learn of the mental capacities of the great apes and ourselves? My own ultimate purpose is to use comparative evidence from living species to reconstruct the evolutionary history of the many cognitive traits that came together to make human psychology. The cognition of great apes is the obvious starting point, to trace the more primitive (i.e. ancient) cognitive aptitudes that are still important to us today. In this chapter, I focus on great ape cognition as it is expressed in manual skills, based on cognitive aspects of tool use and manufacture considered significant in the human evolutionary lineage.Group identification and perceived discrimination : a study of international students in the UKRamos, Miguel R.https://hdl.handle.net/10023/9342019-07-01T10:06:34Z2010-06-23T00:00:00ZThis thesis examined how international students experience life in the UK and,
in particular, how these students respond to experiences with discrimination and
social exclusion. Specifically, we drew on the rejection-identification model
(Branscombe et al., 1999) in order to examine the impact of minority group
identification as a coping strategy against perceptions of discrimination. Despite the
number of studies supporting the rejection-identification model (e.g. Schmitt et al., 2002, Schmitt et al., 2003), discrepant findings were found in other research (e.g. McCoy & Major, 2003; Eccleston & Major, 2006). In order to solve these
inconsistencies we proposed to extend this model in two important ways. Firstly,
building on important work on the multidimensionality of social identification (e.g. Cameron & Lalonde, 2001; Ellemers et al., 1999; Jackson, 2002), we argued that a
multidimensional perspective of the rejection-identification model is fundamental
given that different dimensions of social identification (i.e. ingroup affect, centrality, and ingroup ties) have different effects on psychological well-being. Secondly, we hypothesised that the protective effect of the different dimensions of social
identification depended upon individual preferences, beliefs and behaviours towards
own and host group (i.e. acculturation strategies). These two extensions to the
rejection-identification model were tested longitudinally with a sample of 160
international students. Results indicated that none of the dimensions of social
identification serve to protect students from the harmful effects of discrimination.
Indeed, support was found for the argument that it is important to investigate possible
moderators of the rejection-identification relationship. Our results also indicated that
when international students perceive discrimination, a separation strategy allows them to maintain ingroup affect, and in this way protect their self-esteem. Integration,
marginalisation, and assimilation strategies were associated with lower ingroup affect
leaving these students without a successful strategy to cope with discrimination.
Although the aim of this thesis was to examine the experiences of international
students, in Chapter 7 we replicated our previous model with a sample of Polish
immigrants (N = 66) in order to test whether our results could be generalised to other
minority groups. Results supported the previous findings with international students. Finally, the discussion of this thesis focused on the importance of taking into account individual acculturation strategies in order to understand the relation between perceived discrimination, minority group identification, and well-being. We also focused on how the knowledge generated by this research may support international students.
2010-06-23T00:00:00ZRamos, Miguel R.This thesis examined how international students experience life in the UK and,
in particular, how these students respond to experiences with discrimination and
social exclusion. Specifically, we drew on the rejection-identification model
(Branscombe et al., 1999) in order to examine the impact of minority group
identification as a coping strategy against perceptions of discrimination. Despite the
number of studies supporting the rejection-identification model (e.g. Schmitt et al., 2002, Schmitt et al., 2003), discrepant findings were found in other research (e.g. McCoy & Major, 2003; Eccleston & Major, 2006). In order to solve these
inconsistencies we proposed to extend this model in two important ways. Firstly,
building on important work on the multidimensionality of social identification (e.g. Cameron & Lalonde, 2001; Ellemers et al., 1999; Jackson, 2002), we argued that a
multidimensional perspective of the rejection-identification model is fundamental
given that different dimensions of social identification (i.e. ingroup affect, centrality, and ingroup ties) have different effects on psychological well-being. Secondly, we hypothesised that the protective effect of the different dimensions of social
identification depended upon individual preferences, beliefs and behaviours towards
own and host group (i.e. acculturation strategies). These two extensions to the
rejection-identification model were tested longitudinally with a sample of 160
international students. Results indicated that none of the dimensions of social
identification serve to protect students from the harmful effects of discrimination.
Indeed, support was found for the argument that it is important to investigate possible
moderators of the rejection-identification relationship. Our results also indicated that
when international students perceive discrimination, a separation strategy allows them to maintain ingroup affect, and in this way protect their self-esteem. Integration,
marginalisation, and assimilation strategies were associated with lower ingroup affect
leaving these students without a successful strategy to cope with discrimination.
Although the aim of this thesis was to examine the experiences of international
students, in Chapter 7 we replicated our previous model with a sample of Polish
immigrants (N = 66) in order to test whether our results could be generalised to other
minority groups. Results supported the previous findings with international students. Finally, the discussion of this thesis focused on the importance of taking into account individual acculturation strategies in order to understand the relation between perceived discrimination, minority group identification, and well-being. We also focused on how the knowledge generated by this research may support international students.Social information gathering in lemursRuiz, April M.https://hdl.handle.net/10023/9082019-04-01T10:42:17Z2010-06-01T00:00:00ZBy investigating the cognitive capacities of non-human primates, we can begin to understand the cognitive capacities of the evolutionary ancestors we share with these species. While there is a great deal of research exploring the socio-cognitive abilities of simian primates, prosimians have not been sufficiently studied. Without data from these species, our knowledge about the evolution of the primate mind is limited to the common ancestor shared between simian primates only, precluding understanding of the phylogenetic origins of certain phenomena.
I explored the socio-cognitive capacities of lemurs, a type of prosimian primate. I studied several areas of social cognition related to social referencing, defined as the ability to use and seek out social information when appraising objects or events. As social referencing is a popular subject in both human developmental and non-human primate literature, I aimed to determine how prosimians’ capacities compare.
My research was conducted with captive lemurs of three species: Eulemur fulvus fulvus, Eulemur macaco macaco, and Eulemur fulvus rufus. I found that lemurs use social cues regarding food palatability to modify their own feeding behaviour and that they visually attend to conspecifics differently when presented with novel, as compared to familiar, foods. Lemurs also visually referred to a human experimenter’s face when presented with an anomalous interaction and went on to engage in gaze alternation. Lemurs failed to use information about the experimenter’s attentional state, however, when modifying their use of a trained gesture. Finally, I found that lemurs are able to visually co-orient with conspecifics, correctly prioritising information from the head over that from the body, and that they go on to use conspecific gaze to locate hidden resources.
These results show that lemurs are more cognitively advanced than previously thought and the origins of some social referencing skills may be phylogenetically older than previously hypothesised.
2010-06-01T00:00:00ZRuiz, April M.By investigating the cognitive capacities of non-human primates, we can begin to understand the cognitive capacities of the evolutionary ancestors we share with these species. While there is a great deal of research exploring the socio-cognitive abilities of simian primates, prosimians have not been sufficiently studied. Without data from these species, our knowledge about the evolution of the primate mind is limited to the common ancestor shared between simian primates only, precluding understanding of the phylogenetic origins of certain phenomena.
I explored the socio-cognitive capacities of lemurs, a type of prosimian primate. I studied several areas of social cognition related to social referencing, defined as the ability to use and seek out social information when appraising objects or events. As social referencing is a popular subject in both human developmental and non-human primate literature, I aimed to determine how prosimians’ capacities compare.
My research was conducted with captive lemurs of three species: Eulemur fulvus fulvus, Eulemur macaco macaco, and Eulemur fulvus rufus. I found that lemurs use social cues regarding food palatability to modify their own feeding behaviour and that they visually attend to conspecifics differently when presented with novel, as compared to familiar, foods. Lemurs also visually referred to a human experimenter’s face when presented with an anomalous interaction and went on to engage in gaze alternation. Lemurs failed to use information about the experimenter’s attentional state, however, when modifying their use of a trained gesture. Finally, I found that lemurs are able to visually co-orient with conspecifics, correctly prioritising information from the head over that from the body, and that they go on to use conspecific gaze to locate hidden resources.
These results show that lemurs are more cognitively advanced than previously thought and the origins of some social referencing skills may be phylogenetically older than previously hypothesised.Refinement of biologically inspired models of reinforcement learningAquili, Lucahttps://hdl.handle.net/10023/8862019-04-01T10:42:06Z2010-06-01T00:00:00ZReinforcement learning occurs when organisms adapt the propensities of
given behaviours on the basis of associations with reward and punishment. Currently,
reinforcement learning models have been validated in minimalist environments in
which only 1-2 environmental stimuli are present as possible predictors of reward.
The exception to this is two studies in which the responses of the dopamine system to
configurations of multiple stimuli were investigated, however, in both cases the
stimuli were presented simultaneously rather than in a sequence.
Therefore, we set out to understand how current models of reinforcement
learning would respond under more complex conditions in which sequences of events
are predictors of reward. In the two experimental chapters of this thesis, we attempted
to understand whether midbrain dopaminergic neurons would respond to occasion
setters (Chapter 3), and to the overexpectation effect (Chapter 4). In addition, we ran
simulations of the behavioural paradigms using temporal difference models of
reinforcement learning (Chapter 2) and compared the predictions of the model with
the behavioural and neurophysiological data.
In Chapter 3, by performing single-neuron recording from VTA and SNpc
dopaminergic cells, we demonstrated that our population of neurons were most
responsive to the latest predictor of reward, the conditioned stimulus (CS) and not the
earliest, the occasion setter (the OS). This is in stark contrast with the predictions of
the model (Chapter 2), where the greatest response is seen at the OS onset. We also
showed at a neural level that there was only a weak enhancement of the response to
the discriminative stimulus (SD) when this was preceded by the OS. On the other
hand, at a behavioural level, bar pressing was greatest when the SD was preceded by
the OS, demonstrating that rats could use the information provided by the OS, but that
dopamine was not controlling the conditioned response.
In Chapter 4, our population of dopaminergic neurons showed that they would
preferentially respond to only one of the two conditioned stimuli (CSA, CSB) in the
overexpectation paradigm. The predictions of the model (Chapter 2) suggested that
when the two stimuli would be presented in compound, there would be an inhibitory
response if the reward magnitude was kept constant and an excitatory response if the
reward magnitude was doubled. The lack of neural firing to one of the two
conditioned stimuli, however, does not make for easy interpretation of the data.
Perhaps, one of the conditioned stimuli acted as if it were overshadowing the
other, resulting in no response to the second CS. Interestingly, at a behavioural level,
we did not see increased licking frequency to the compound stimuli presentation, a
result that is somewhat at odds with the previous literature.
Overall, the results of our experimental chapters suggest that the role that
midbrain dopaminergic neurons play in reinforcement learning is more complex than
that envisaged by previous investigations.
2010-06-01T00:00:00ZAquili, LucaReinforcement learning occurs when organisms adapt the propensities of
given behaviours on the basis of associations with reward and punishment. Currently,
reinforcement learning models have been validated in minimalist environments in
which only 1-2 environmental stimuli are present as possible predictors of reward.
The exception to this is two studies in which the responses of the dopamine system to
configurations of multiple stimuli were investigated, however, in both cases the
stimuli were presented simultaneously rather than in a sequence.
Therefore, we set out to understand how current models of reinforcement
learning would respond under more complex conditions in which sequences of events
are predictors of reward. In the two experimental chapters of this thesis, we attempted
to understand whether midbrain dopaminergic neurons would respond to occasion
setters (Chapter 3), and to the overexpectation effect (Chapter 4). In addition, we ran
simulations of the behavioural paradigms using temporal difference models of
reinforcement learning (Chapter 2) and compared the predictions of the model with
the behavioural and neurophysiological data.
In Chapter 3, by performing single-neuron recording from VTA and SNpc
dopaminergic cells, we demonstrated that our population of neurons were most
responsive to the latest predictor of reward, the conditioned stimulus (CS) and not the
earliest, the occasion setter (the OS). This is in stark contrast with the predictions of
the model (Chapter 2), where the greatest response is seen at the OS onset. We also
showed at a neural level that there was only a weak enhancement of the response to
the discriminative stimulus (SD) when this was preceded by the OS. On the other
hand, at a behavioural level, bar pressing was greatest when the SD was preceded by
the OS, demonstrating that rats could use the information provided by the OS, but that
dopamine was not controlling the conditioned response.
In Chapter 4, our population of dopaminergic neurons showed that they would
preferentially respond to only one of the two conditioned stimuli (CSA, CSB) in the
overexpectation paradigm. The predictions of the model (Chapter 2) suggested that
when the two stimuli would be presented in compound, there would be an inhibitory
response if the reward magnitude was kept constant and an excitatory response if the
reward magnitude was doubled. The lack of neural firing to one of the two
conditioned stimuli, however, does not make for easy interpretation of the data.
Perhaps, one of the conditioned stimuli acted as if it were overshadowing the
other, resulting in no response to the second CS. Interestingly, at a behavioural level,
we did not see increased licking frequency to the compound stimuli presentation, a
result that is somewhat at odds with the previous literature.
Overall, the results of our experimental chapters suggest that the role that
midbrain dopaminergic neurons play in reinforcement learning is more complex than
that envisaged by previous investigations.Maintaining personhood and self-image in dementia : an exploration of collaborative communicationEllis, Maggie P.https://hdl.handle.net/10023/8442019-04-01T10:41:11Z2009-01-01T00:00:00ZThe main aim of this thesis was to explore the maintenance of personhood and
self-image in dementia by way of facilitating collaborative communication between
people with dementia and their caregivers/interaction partners. As such, the roles of
the person with dementia and the interaction partner were examined in each study
within the realms of the ‘Collaborative Personhood Model’.
Findings of the first study highlighted strategies used by people with mild to
severe dementia to maintain social interactions, to save-face and to maintain and
project a sense of self-image in a reminiscence situation. The impact of introducing a
family member as the interaction partner in a similar reminiscence-based situation
using personal photographs was then explored. The findings of this study indicated
that the personal nature of the photographs can create conflict between the person with
dementia and her family member. Crucially, these studies illuminated the supportive
role that the communication partner must adopt in order to successfully facilitate
people with dementia to maximise their retained communication skills.
Communication and sense of self was then examined in an individual with very severe
dementia with some retained speech. The findings of this study illuminated the
potential of imitation in communicating with people at this stage of the illness. These
findings were then built upon by exploring the use of Intensive Interaction (II) in a
person with very advanced dementia with no retained speech. Findings of this study
indicated retained awareness of self and functional communication skills at very late
stages of dementia. Finally, this study was expanded using a modified version of II
(Adaptive Interaction) in a small group of individuals with very severe dementia with
very little or no retained speech. These findings indicated an unprecedented desire and
ability to communicate in people with such severe dementia.
Taken as a whole, these studies highlighted the adaptive and collaborative role
that the interaction partner must adopt in order to facilitate the maintenance of
personhood and self-image in people with dementia. More specifically, the interaction
partner must adjust to the communicative repertoire that is maintained at each stage of
dementia and in each individual. The ‘Collaborative Personhood Model’ represents an
attempt to explain how this might be achieved.
2009-01-01T00:00:00ZEllis, Maggie P.The main aim of this thesis was to explore the maintenance of personhood and
self-image in dementia by way of facilitating collaborative communication between
people with dementia and their caregivers/interaction partners. As such, the roles of
the person with dementia and the interaction partner were examined in each study
within the realms of the ‘Collaborative Personhood Model’.
Findings of the first study highlighted strategies used by people with mild to
severe dementia to maintain social interactions, to save-face and to maintain and
project a sense of self-image in a reminiscence situation. The impact of introducing a
family member as the interaction partner in a similar reminiscence-based situation
using personal photographs was then explored. The findings of this study indicated
that the personal nature of the photographs can create conflict between the person with
dementia and her family member. Crucially, these studies illuminated the supportive
role that the communication partner must adopt in order to successfully facilitate
people with dementia to maximise their retained communication skills.
Communication and sense of self was then examined in an individual with very severe
dementia with some retained speech. The findings of this study illuminated the
potential of imitation in communicating with people at this stage of the illness. These
findings were then built upon by exploring the use of Intensive Interaction (II) in a
person with very advanced dementia with no retained speech. Findings of this study
indicated retained awareness of self and functional communication skills at very late
stages of dementia. Finally, this study was expanded using a modified version of II
(Adaptive Interaction) in a small group of individuals with very severe dementia with
very little or no retained speech. These findings indicated an unprecedented desire and
ability to communicate in people with such severe dementia.
Taken as a whole, these studies highlighted the adaptive and collaborative role
that the interaction partner must adopt in order to facilitate the maintenance of
personhood and self-image in people with dementia. More specifically, the interaction
partner must adjust to the communicative repertoire that is maintained at each stage of
dementia and in each individual. The ‘Collaborative Personhood Model’ represents an
attempt to explain how this might be achieved.Anti-predator behaviour of Guereza colobus monkeys (Colobus guereza)Schel, Anne Marijkehttps://hdl.handle.net/10023/8322019-04-01T10:41:44Z2009-06-24T00:00:00ZBlack-and-white colobus monkeys are renowned for their impressive vocal behaviour, but up to date there have been only very few systematic efforts to study this. These monkeys are able to produce loud and low-pitched roars that transmit over long distances, which has lead to the assumption that these calls function in inter-group spacing and male-male competition. The fact that the monkeys sometimes produce the same calls to predators as well, has not received much attention so far.
This thesis presents a detailed description of the form and function of the anti-predator behaviour of one species of black-and-white colobus monkeys, the Guereza (Colobus guereza), with a specific focus on their alarm calling behaviour. A second aim was to determine the effects of predator experience on their anti-predator behaviour, with a specific focus on call comprehension and production. Data were collected from two populations of Guereza monkeys in the Budongo Forest Reserve, Uganda, that differ in predation pressures experienced by their main predators: leopards, eagles and chimpanzees. Results showed that Guerezas use a basic form of zoo-syntax in order to compose predator-specific call sequences that vary in the number of roaring phrases and snorts. These sequences are meaningful to recipients, at least at the level of the predator class, but there were also indications for additional levels of encoded information: Guerezas appear to have evolved a second system, based on acoustic variants of individual phrases, which allows them to narrow down the information content of call sequences, generating the potential to communicate highly specific information by using a mix of syntactic and semantic cues.
The monkeys’ vocal behaviour was influenced by predator experience, but not strongly so. Monkeys without prior experience with leopards lacked some of the behavioural nuances seen in leopard-experienced monkeys, but they nevertheless responded appropriately to visual and acoustic leopard models, suggesting they had retained the basic capacities to recognise this predator type as relevant and dangerous.
Results are discussed in light of the comparative approach to the study of human language evolution. Although human language is unique in a number of ways, for example through its use of complex syntax and intentional semantics, some animal communication systems have revealed similar features, and Guerezas, the first member of the colobine family to be studied in this respect, are no exception. The Guerezas’ alarm calling behaviour is complex and flexible, and these monkeys have provided another piece of empirical evidence that is directly relevant for the comparative approach to human language evolution.
2009-06-24T00:00:00ZSchel, Anne MarijkeBlack-and-white colobus monkeys are renowned for their impressive vocal behaviour, but up to date there have been only very few systematic efforts to study this. These monkeys are able to produce loud and low-pitched roars that transmit over long distances, which has lead to the assumption that these calls function in inter-group spacing and male-male competition. The fact that the monkeys sometimes produce the same calls to predators as well, has not received much attention so far.
This thesis presents a detailed description of the form and function of the anti-predator behaviour of one species of black-and-white colobus monkeys, the Guereza (Colobus guereza), with a specific focus on their alarm calling behaviour. A second aim was to determine the effects of predator experience on their anti-predator behaviour, with a specific focus on call comprehension and production. Data were collected from two populations of Guereza monkeys in the Budongo Forest Reserve, Uganda, that differ in predation pressures experienced by their main predators: leopards, eagles and chimpanzees. Results showed that Guerezas use a basic form of zoo-syntax in order to compose predator-specific call sequences that vary in the number of roaring phrases and snorts. These sequences are meaningful to recipients, at least at the level of the predator class, but there were also indications for additional levels of encoded information: Guerezas appear to have evolved a second system, based on acoustic variants of individual phrases, which allows them to narrow down the information content of call sequences, generating the potential to communicate highly specific information by using a mix of syntactic and semantic cues.
The monkeys’ vocal behaviour was influenced by predator experience, but not strongly so. Monkeys without prior experience with leopards lacked some of the behavioural nuances seen in leopard-experienced monkeys, but they nevertheless responded appropriately to visual and acoustic leopard models, suggesting they had retained the basic capacities to recognise this predator type as relevant and dangerous.
Results are discussed in light of the comparative approach to the study of human language evolution. Although human language is unique in a number of ways, for example through its use of complex syntax and intentional semantics, some animal communication systems have revealed similar features, and Guerezas, the first member of the colobine family to be studied in this respect, are no exception. The Guerezas’ alarm calling behaviour is complex and flexible, and these monkeys have provided another piece of empirical evidence that is directly relevant for the comparative approach to human language evolution.Intra-sexual competition and vocal counter-strategies in wild female chimpanzees (Pan troglodytes schweinfurthii)Townsend, Simon W.https://hdl.handle.net/10023/7742019-04-01T10:42:21Z2009-01-01T00:00:00ZA growing body of behavioural data is beginning to show that, like their male counterparts,
female chimpanzees can be competitive and aggressive, particularly when resources come
under pressure. These observations are especially surprising because, for a long time, females
were simply considered passive pawns of male social manoeuvrings. While we are beginning
to understand the complexities surrounding female chimpanzee group living, exactly how
females manage these social pressures is unclear. In this thesis I address this by focusing on
female competition in wild chimpanzees and the importance of vocal counter-strategies.
I examined two commonly produced female vocalisations: copulation calls and victim
screams from chimpanzees (Pan troglodytes schweinfurthii) in the Budongo Forest, Uganda.
My results regarding the production and acoustic structure of copulation calls suggests that
these vocalisations play a crucial role in the lives of female chimpanzees, dissipating the risks
associated with female competition.
During aggression, chimpanzee females commonly produce victim screams and these calls
have been shown to vary systematically with the severity of aggression experienced. A
playback experiment showed that victim screams are meaningful to females and that listeners
do not just respond to the acoustically most salient signals in their environment. Females may
use this information to keep track of out-of-sight agonistic interactions and make appropriate
social decisions regarding whether to avoid an ensuing attack.
Taken together, I propose that vocalisations may represent important behavioural counter-strategies, enabling females to navigate successfully through their socially intricate world.
2009-01-01T00:00:00ZTownsend, Simon W.A growing body of behavioural data is beginning to show that, like their male counterparts,
female chimpanzees can be competitive and aggressive, particularly when resources come
under pressure. These observations are especially surprising because, for a long time, females
were simply considered passive pawns of male social manoeuvrings. While we are beginning
to understand the complexities surrounding female chimpanzee group living, exactly how
females manage these social pressures is unclear. In this thesis I address this by focusing on
female competition in wild chimpanzees and the importance of vocal counter-strategies.
I examined two commonly produced female vocalisations: copulation calls and victim
screams from chimpanzees (Pan troglodytes schweinfurthii) in the Budongo Forest, Uganda.
My results regarding the production and acoustic structure of copulation calls suggests that
these vocalisations play a crucial role in the lives of female chimpanzees, dissipating the risks
associated with female competition.
During aggression, chimpanzee females commonly produce victim screams and these calls
have been shown to vary systematically with the severity of aggression experienced. A
playback experiment showed that victim screams are meaningful to females and that listeners
do not just respond to the acoustically most salient signals in their environment. Females may
use this information to keep track of out-of-sight agonistic interactions and make appropriate
social decisions regarding whether to avoid an ensuing attack.
Taken together, I propose that vocalisations may represent important behavioural counter-strategies, enabling females to navigate successfully through their socially intricate world.Skin colour, pigmentation and the perceived health of human facesStephen, Ian Davidhttps://hdl.handle.net/10023/7532019-07-01T10:05:32Z2009-11-11T00:00:00ZMany non-human animal species use colour to signal dominance, condition or reproductive status. These signals have not previously been noted in humans. This thesis investigates the effects of skin colouration and pigmentation on the apparent health of human faces.
Section 2 showed that individuals with increased fruit and vegetable and carotenoid consumption have yellower skin (Study 1) due to increased carotenoid pigmentation in the skin (Study 2).
In Section 3, participants enhanced the redness, yellowness and lightness of the skin portions of colour-calibrated facial photographs to optimise healthy appearance. This suggests roles for blood (red) and carotenoid/melanin (yellow) colouration in providing perceptible cues to health. The contrast between lips and facial skin colour was not found to affect the apparent health of the faces, except in the b* (yellowness) axis, where enhanced facial yellowness caused an apparent blue tint to the lips.
In Section 4 participants enhanced empirically-derived oxygenated blood colour more than deoxygenated blood colour to optimise healthy appearance. In two-dimensional trials, when both blood colour axes could be manipulated simultaneously, deoxygenated blood colour was removed and replaced with oxygenated blood colour. Oxygenated blood colouration appears to drive the preference for redness in faces.
In Section 5 participants increased carotenoid colour significantly more than they increased melanin colour in both single-axis and two-dimensional trials. Carotenoid colour appears to drive the preference for yellowness in faces.
In a cross-cultural study (Section 6), preferences for red and yellow in faces were unaffected by face or participant ethnicity, while African participants lightened faces more than UK participants. A preference for more redness in East Asian faces was explained by this group’s lower initial redness.
The thesis concludes that pigments that provide sexually-selected signals of quality in many non-human animal species – carotenoids and oxygenated blood - also provide perceptible cues to health in human faces.
2009-11-11T00:00:00ZStephen, Ian DavidMany non-human animal species use colour to signal dominance, condition or reproductive status. These signals have not previously been noted in humans. This thesis investigates the effects of skin colouration and pigmentation on the apparent health of human faces.
Section 2 showed that individuals with increased fruit and vegetable and carotenoid consumption have yellower skin (Study 1) due to increased carotenoid pigmentation in the skin (Study 2).
In Section 3, participants enhanced the redness, yellowness and lightness of the skin portions of colour-calibrated facial photographs to optimise healthy appearance. This suggests roles for blood (red) and carotenoid/melanin (yellow) colouration in providing perceptible cues to health. The contrast between lips and facial skin colour was not found to affect the apparent health of the faces, except in the b* (yellowness) axis, where enhanced facial yellowness caused an apparent blue tint to the lips.
In Section 4 participants enhanced empirically-derived oxygenated blood colour more than deoxygenated blood colour to optimise healthy appearance. In two-dimensional trials, when both blood colour axes could be manipulated simultaneously, deoxygenated blood colour was removed and replaced with oxygenated blood colour. Oxygenated blood colouration appears to drive the preference for redness in faces.
In Section 5 participants increased carotenoid colour significantly more than they increased melanin colour in both single-axis and two-dimensional trials. Carotenoid colour appears to drive the preference for yellowness in faces.
In a cross-cultural study (Section 6), preferences for red and yellow in faces were unaffected by face or participant ethnicity, while African participants lightened faces more than UK participants. A preference for more redness in East Asian faces was explained by this group’s lower initial redness.
The thesis concludes that pigments that provide sexually-selected signals of quality in many non-human animal species – carotenoids and oxygenated blood - also provide perceptible cues to health in human faces.Social learning and behaviour transmission in brown capuchin monkeys (Cebus apella)Dindo, Mariettahttps://hdl.handle.net/10023/7402019-04-01T10:42:00Z2009-06-24T00:00:00ZThe research aims of this thesis are to experimentally investigate how behaviours
spread socially, and what factors contribute to the development of group-wide
social traditions in capuchins (Cebus apella). Given the apparent convergent
evolution between such monkeys and great apes, capuchin traditions are of great
interest anthropologically and for a biological and psychological understanding of
culture. Several studies have investigated social learning in capuchins, but few have
made headway into understanding how it supports the development of traditions
either in the wild or in captivity. By experimentally introducing novel foraging
behaviours into several captive groups, the studies included in this thesis simulate
the development of foraging behaviours so that their spread can be studied from
various viewpoints. Five experiments are presented investigating: (1) the chained
transmission of foraging behaviours, (2) the role of social facilitation on the rate of
individual learning, (3) the fidelity of learning from localised stimulus enhancement
& object-movement re-enactment, (4) the quality of individual relationships in the
social transmission of novel foraging techniques, and (5) the open diffusion of
group-specific foraging behaviours in capuchin monkeys. Together, these
experiments explore how traditions may develop, ranging from individual learning
to how behaviour patterns may spread socially based on social ties within the
group.
2009-06-24T00:00:00ZDindo, MariettaThe research aims of this thesis are to experimentally investigate how behaviours
spread socially, and what factors contribute to the development of group-wide
social traditions in capuchins (Cebus apella). Given the apparent convergent
evolution between such monkeys and great apes, capuchin traditions are of great
interest anthropologically and for a biological and psychological understanding of
culture. Several studies have investigated social learning in capuchins, but few have
made headway into understanding how it supports the development of traditions
either in the wild or in captivity. By experimentally introducing novel foraging
behaviours into several captive groups, the studies included in this thesis simulate
the development of foraging behaviours so that their spread can be studied from
various viewpoints. Five experiments are presented investigating: (1) the chained
transmission of foraging behaviours, (2) the role of social facilitation on the rate of
individual learning, (3) the fidelity of learning from localised stimulus enhancement
& object-movement re-enactment, (4) the quality of individual relationships in the
social transmission of novel foraging techniques, and (5) the open diffusion of
group-specific foraging behaviours in capuchin monkeys. Together, these
experiments explore how traditions may develop, ranging from individual learning
to how behaviour patterns may spread socially based on social ties within the
group.The effects of pubertal timing and dominance on the mating strategy, appearance and behaviour of menLawson, Jamie F.https://hdl.handle.net/10023/7062019-04-01T10:42:05Z2008-01-01T00:00:00ZPubertal timing is a human life history variable representing a trade-off between early reproduction and continued growth. Dominance is an important feature to male mate value. These two variables should have far-reaching effects on adult male life. Chapter 1 reviews evolution, r/K selection and life history theory to derive hypotheses concerning variation in male mating strategy. Chapters 2-4 investigate the effects of pubertal timing and dominance on mating strategy using sociosexual orientation and preferences for faces and mate characteristics. Both early puberty and high dominance associate with unrestricted sociosexuality (increased interest in casual sex) as predicted. Dominance is shown to relate to preferences for cues of sociosexuality but not femininity, while pubertal timing relates to neither facial characteristic. Earlier and later developing men do not differ in their mate characteristic preferences, while dominant men exhibit enhanced female-typical mate preferences counter to predictions. A dominance-dependent, dual, male mating strategy is proposed to account for results. Chapter 5 introduces sensitivity to putative human pheromones as an indicator of mating strategy. Dominant men are found to be more sensitive to and more averse to a putative female pheromone. Pubertal timing has no effect on sensitivity. Results are interpreted in terms of dominant male avoidance of infertile matings.
Chapter 6 finds that early puberty associates with facial masculinity, attractiveness and apparent age. Chapter 7 offers a hormonal underpinning of effects related to pubertal timing, showing that early development associates with higher levels of testosterone in men. Chapter 8 uses digit length ratios to show that early developing men may have been exposed to greater levels of uterine testosterone, suggesting prenatal influences on male pubertal timing. Chapter 9 shows dominance associates with bodily, vocal and general attractiveness but not facial attractiveness. Chapter 10 reports that dominance associates with high levels of the stress hormone cortisol, suggesting costs of high dominance. Chapter 11 shows early pubertal timing relates to the visual appearance of skin, perhaps because of lower sebum production among early developing men, leading to them having darker, less reflective skin. This may reflect accelerated ageing of early developing males, potentially representing a cost to longevity.
2008-01-01T00:00:00ZLawson, Jamie F.Pubertal timing is a human life history variable representing a trade-off between early reproduction and continued growth. Dominance is an important feature to male mate value. These two variables should have far-reaching effects on adult male life. Chapter 1 reviews evolution, r/K selection and life history theory to derive hypotheses concerning variation in male mating strategy. Chapters 2-4 investigate the effects of pubertal timing and dominance on mating strategy using sociosexual orientation and preferences for faces and mate characteristics. Both early puberty and high dominance associate with unrestricted sociosexuality (increased interest in casual sex) as predicted. Dominance is shown to relate to preferences for cues of sociosexuality but not femininity, while pubertal timing relates to neither facial characteristic. Earlier and later developing men do not differ in their mate characteristic preferences, while dominant men exhibit enhanced female-typical mate preferences counter to predictions. A dominance-dependent, dual, male mating strategy is proposed to account for results. Chapter 5 introduces sensitivity to putative human pheromones as an indicator of mating strategy. Dominant men are found to be more sensitive to and more averse to a putative female pheromone. Pubertal timing has no effect on sensitivity. Results are interpreted in terms of dominant male avoidance of infertile matings.
Chapter 6 finds that early puberty associates with facial masculinity, attractiveness and apparent age. Chapter 7 offers a hormonal underpinning of effects related to pubertal timing, showing that early development associates with higher levels of testosterone in men. Chapter 8 uses digit length ratios to show that early developing men may have been exposed to greater levels of uterine testosterone, suggesting prenatal influences on male pubertal timing. Chapter 9 shows dominance associates with bodily, vocal and general attractiveness but not facial attractiveness. Chapter 10 reports that dominance associates with high levels of the stress hormone cortisol, suggesting costs of high dominance. Chapter 11 shows early pubertal timing relates to the visual appearance of skin, perhaps because of lower sebum production among early developing men, leading to them having darker, less reflective skin. This may reflect accelerated ageing of early developing males, potentially representing a cost to longevity.An investigation into the role of thought suppression in the retrieval of autobiographical memoriesNeufeind, Juliahttps://hdl.handle.net/10023/6862019-07-01T10:03:20Z2008-11-27T00:00:00ZThis program of research was designed to examine the role of thought suppression in the retrieval of autobiographical memories (ABMs). The principal theory proposed here is that thought suppression is an important mechanism in explaining certain ABM retrieval patterns relevant to trauma and self-harm. Study 1 examined the role of thought suppression as a correlate of ABM retrieval in a nonclinical student sample, and showed that higher levels of thought suppression were significantly correlated with the faster recall of negative episodic ABMs as well as the recall of fewer personal semantic memories. Study 2 used a suppression manipulation procedure designed to examine whether this was a causal relationship, and revealed that induced thought suppression directly led to a significant enhancement in the retrieval of negative episodic ABMs as well as significantly fewer overgeneral first responses to negative cues. Furthermore, the induced thought suppression also resulted in the recall of significantly fewer personal semantic memories. Together these results support the theory that thought suppression is an important factor in ABM recall. The enhanced recall of negative memories could be particularly important in individuals who are self-harming, suicidal and/or suffering from PTSD, as enhanced negative recall has previously been observed in these populations. In order to further examine how thought suppression affects ABM retrieval and whether the enhanced negative recall observed in Study 2 was a result of mood-congruent recall, Study 3 used a similar suppression manipulation paradigm to examine the effects of induced thought suppression on mood. The results suggested that the enhanced negative ABM recall was unlikely to have been a by-product of the suppression manipulation resulting in a more negative mood state. Finally, Study 4 examined the role of thought suppression and ABM recall in a clinical sample of self-harming adolescents (who also reported high levels of post-traumatic stress symptoms). The results showed that levels of thought suppression were significantly higher in the self-harmers than the control group, indicating that thought suppression is an important coping mechanism in self-harmers. Furthermore, in terms of the autobiographical memory retrieval, it was found that the self-harmers were significantly faster in their retrieval of negative episodic ABMs and recalled fewer personal semantic memories than the control group. Multiple regression analysis of the data revealed that thought suppression remained as the most important predictor of variability in negative episodic ABM retrieval and personal semantic memory retrieval, even when variability explained by symptoms of depression and PTSD was considered. This program of research extends current theories of ABM retrieval by identifying thought suppression as a cognitive mechanism that directly affects the retrieval of both episodic as well as personal semantic ABMs. The theoretical importance and clinical relevance of this program of research are discussed.
2008-11-27T00:00:00ZNeufeind, JuliaThis program of research was designed to examine the role of thought suppression in the retrieval of autobiographical memories (ABMs). The principal theory proposed here is that thought suppression is an important mechanism in explaining certain ABM retrieval patterns relevant to trauma and self-harm. Study 1 examined the role of thought suppression as a correlate of ABM retrieval in a nonclinical student sample, and showed that higher levels of thought suppression were significantly correlated with the faster recall of negative episodic ABMs as well as the recall of fewer personal semantic memories. Study 2 used a suppression manipulation procedure designed to examine whether this was a causal relationship, and revealed that induced thought suppression directly led to a significant enhancement in the retrieval of negative episodic ABMs as well as significantly fewer overgeneral first responses to negative cues. Furthermore, the induced thought suppression also resulted in the recall of significantly fewer personal semantic memories. Together these results support the theory that thought suppression is an important factor in ABM recall. The enhanced recall of negative memories could be particularly important in individuals who are self-harming, suicidal and/or suffering from PTSD, as enhanced negative recall has previously been observed in these populations. In order to further examine how thought suppression affects ABM retrieval and whether the enhanced negative recall observed in Study 2 was a result of mood-congruent recall, Study 3 used a similar suppression manipulation paradigm to examine the effects of induced thought suppression on mood. The results suggested that the enhanced negative ABM recall was unlikely to have been a by-product of the suppression manipulation resulting in a more negative mood state. Finally, Study 4 examined the role of thought suppression and ABM recall in a clinical sample of self-harming adolescents (who also reported high levels of post-traumatic stress symptoms). The results showed that levels of thought suppression were significantly higher in the self-harmers than the control group, indicating that thought suppression is an important coping mechanism in self-harmers. Furthermore, in terms of the autobiographical memory retrieval, it was found that the self-harmers were significantly faster in their retrieval of negative episodic ABMs and recalled fewer personal semantic memories than the control group. Multiple regression analysis of the data revealed that thought suppression remained as the most important predictor of variability in negative episodic ABM retrieval and personal semantic memory retrieval, even when variability explained by symptoms of depression and PTSD was considered. This program of research extends current theories of ABM retrieval by identifying thought suppression as a cognitive mechanism that directly affects the retrieval of both episodic as well as personal semantic ABMs. The theoretical importance and clinical relevance of this program of research are discussed.Social learning in mother-reared and "enculturated" capuchin monkeysFredman, Tamarhttps://hdl.handle.net/10023/6812019-04-01T10:42:01Z2008-01-01T00:00:00ZThis thesis explores social learning in mother-reared and “enculturated” capuchin
monkeys (Cebus apella). At the outset a framework for understanding the social
influence on learning is discussed, followed by a review of the social and cognitive
abilities of capuchin monkeys, establishing the rationale for studying social learning in
this species.
Studies of wild capuchins suggest an important role for social learning but
experiments with captive subjects have generally failed to support this. Some potential
reasons for the lack of evidence in experimental settings are given.
An example of using the two - method design to test social learning in acquiring
behaviour by enculturated subjects is addressed. The results are related to findings with
other species tested with a similar apparatus. Before testing mother-reared monkeys, an
observational study of the object manipulation and tool-use repertoire of the subjects was
carried out in order to facilitate the design of suitable social learning tasks for these
monkeys.
The first empirical study in Chapter 6 reports results of experiments with the
enculturated and mother-reared capuchin monkeys employing the two -action method
together with a third control group. The enculturated monkeys exhibited high fidelity
copying that included the specific tool use technique witnessed while opening the
foraging box. Mother-reared monkeys exhibited fidelity at a lower level, tending only to
re-create the results the model had achieved.
The second empirical study in Chapter 7 tested whether capuchin monkeys could
show cumulative cultural learning manifested in the ability to switch from an established
mode of manipulating a dipping box to a complex yet more advantageous one. Both
populations were able to do so. The enculturated monkeys, as in the previous study,
showed higher fidelity copying of the model.
The last experiment was a preliminary study employing the “do as I do” method
which was carried out with four of the enculturated monkeys. It provides suggestive
evidence for at least one monkey's understanding of the task.
The results of the studies are discussed in relation to previous experimental
research as well as to data from capuchin monkeys in nature. The possible role of
enculturation in social learning ability is considered.
2008-01-01T00:00:00ZFredman, TamarThis thesis explores social learning in mother-reared and “enculturated” capuchin
monkeys (Cebus apella). At the outset a framework for understanding the social
influence on learning is discussed, followed by a review of the social and cognitive
abilities of capuchin monkeys, establishing the rationale for studying social learning in
this species.
Studies of wild capuchins suggest an important role for social learning but
experiments with captive subjects have generally failed to support this. Some potential
reasons for the lack of evidence in experimental settings are given.
An example of using the two - method design to test social learning in acquiring
behaviour by enculturated subjects is addressed. The results are related to findings with
other species tested with a similar apparatus. Before testing mother-reared monkeys, an
observational study of the object manipulation and tool-use repertoire of the subjects was
carried out in order to facilitate the design of suitable social learning tasks for these
monkeys.
The first empirical study in Chapter 6 reports results of experiments with the
enculturated and mother-reared capuchin monkeys employing the two -action method
together with a third control group. The enculturated monkeys exhibited high fidelity
copying that included the specific tool use technique witnessed while opening the
foraging box. Mother-reared monkeys exhibited fidelity at a lower level, tending only to
re-create the results the model had achieved.
The second empirical study in Chapter 7 tested whether capuchin monkeys could
show cumulative cultural learning manifested in the ability to switch from an established
mode of manipulating a dipping box to a complex yet more advantageous one. Both
populations were able to do so. The enculturated monkeys, as in the previous study,
showed higher fidelity copying of the model.
The last experiment was a preliminary study employing the “do as I do” method
which was carried out with four of the enculturated monkeys. It provides suggestive
evidence for at least one monkey's understanding of the task.
The results of the studies are discussed in relation to previous experimental
research as well as to data from capuchin monkeys in nature. The possible role of
enculturation in social learning ability is considered.Developmental mechanisms influencing decision-makingEscalante-Mead, P. R.https://hdl.handle.net/10023/6802019-04-01T10:40:13Z2009-06-24T00:00:00ZThe main aim of this thesis was to investigate decision making from a broad developmental perspective to clarify the role of the underlying mechanisms influencing it. Problem solving and cognitive inhibitory capacity were chartered initially through the use of hypothetical vignettes depicting socially relevant situations and through the use of the Stroop task, to tap into automatic inhibitory capacity. Initial assumptions that prefrontal cortical refinement would denote enhanced social problem ability were not confirmed. Experience emerged as distinct factor in problem solving/decision-making, with the youngest participants equally as effective in producing solutions to situations that they had the most experience in. A shift in development is observed with maturation denoting greater experience and this being applied directly to problem solving and decision-making situations. Education was identified as a possible contributory factor in decision-making and this was explored in a cross-cultural study that tapped into a non-schooled population. The results reinforced the centrality of experience in shaping decision-making.
Decision-making in regards to the use of experience was then looked at through real life decision-making situations, where adolescents were asked to provide their knowledge or experience of situations where risk was involved. Adolescents possessed the necessary knowledge to distinguish between optimal and sub-optimal decisions in terms of the consequences that risk behaviours carried with them. However, many still chose to engage in risky behaviours. This paradox could also be explained by actual experience, with the suggestion that positive experience in a peer group was serving as a pool from which adolescents drew to make future decision-making. If risk behaviours were not experienced adversely, the likelihood of their repetition was high.
Taken together the findings suggest that adolescents are well equipped with the cognitive skills to make decisions. Compared to younger children, they have more experience of a greater range of situations from which to extrapolate responses from. They also have a great deal of knowledge and information about the negative consequences associated with a range of challenging situations and risk-taking behaviours. However, when faced with decisions in the social domain, the behaviour of friends and perceptions of what other people are doing are powerful influences on adolescent decisions.
2009-06-24T00:00:00ZEscalante-Mead, P. R.The main aim of this thesis was to investigate decision making from a broad developmental perspective to clarify the role of the underlying mechanisms influencing it. Problem solving and cognitive inhibitory capacity were chartered initially through the use of hypothetical vignettes depicting socially relevant situations and through the use of the Stroop task, to tap into automatic inhibitory capacity. Initial assumptions that prefrontal cortical refinement would denote enhanced social problem ability were not confirmed. Experience emerged as distinct factor in problem solving/decision-making, with the youngest participants equally as effective in producing solutions to situations that they had the most experience in. A shift in development is observed with maturation denoting greater experience and this being applied directly to problem solving and decision-making situations. Education was identified as a possible contributory factor in decision-making and this was explored in a cross-cultural study that tapped into a non-schooled population. The results reinforced the centrality of experience in shaping decision-making.
Decision-making in regards to the use of experience was then looked at through real life decision-making situations, where adolescents were asked to provide their knowledge or experience of situations where risk was involved. Adolescents possessed the necessary knowledge to distinguish between optimal and sub-optimal decisions in terms of the consequences that risk behaviours carried with them. However, many still chose to engage in risky behaviours. This paradox could also be explained by actual experience, with the suggestion that positive experience in a peer group was serving as a pool from which adolescents drew to make future decision-making. If risk behaviours were not experienced adversely, the likelihood of their repetition was high.
Taken together the findings suggest that adolescents are well equipped with the cognitive skills to make decisions. Compared to younger children, they have more experience of a greater range of situations from which to extrapolate responses from. They also have a great deal of knowledge and information about the negative consequences associated with a range of challenging situations and risk-taking behaviours. However, when faced with decisions in the social domain, the behaviour of friends and perceptions of what other people are doing are powerful influences on adolescent decisions.What do Diana monkeys know about the focus of attention of a conspecific?Scerif, GaiaGómez, Juan CarlosByrne, RWhttps://hdl.handle.net/10023/6602019-04-01T10:37:56Z2004-01-01T00:00:00ZConverging experimental and observational evidence suggests that some non-human primates are able to co-orient with shifts in visual attention, both of conspecifics and humans. However, the underlying cognitive mechanisms involved are unclear. To investigate attention-following in Diana monkeys (Cercopithecus diana diana), we used photographs of familiar conspecifics orienting towards one of two locations. A subject monkey was shown a photograph, and shortly afterwards a toy appeared at one location or the other. The toy’s position therefore either matched the location signalled by the head and body orientation of the photographed monkey (compatible), or was opposite to that location (incompatible). Overall, monkeys’ first inspections, total duration of looking, and number of looks were more likely to be directed to the compatible location, i.e. towards the direction of attention shown in the photograph. Furthermore, when a photograph of an adult monkey signalled attention to one location, but the toy appeared at the opposite (incompatible) location, subjects re-inspected the monkey photographs more often than when the toy appeared at the compatible location, suggesting a violation of expectancy. This effect was not the case if the photograph was of an immature animal. Our results show that attention-following was not limited to simple reflexive orienting by the monkeys, and that monkeys perceived a relationship existing between agent and object of attention.
2004-01-01T00:00:00ZScerif, GaiaGómez, Juan CarlosByrne, RWConverging experimental and observational evidence suggests that some non-human primates are able to co-orient with shifts in visual attention, both of conspecifics and humans. However, the underlying cognitive mechanisms involved are unclear. To investigate attention-following in Diana monkeys (Cercopithecus diana diana), we used photographs of familiar conspecifics orienting towards one of two locations. A subject monkey was shown a photograph, and shortly afterwards a toy appeared at one location or the other. The toy’s position therefore either matched the location signalled by the head and body orientation of the photographed monkey (compatible), or was opposite to that location (incompatible). Overall, monkeys’ first inspections, total duration of looking, and number of looks were more likely to be directed to the compatible location, i.e. towards the direction of attention shown in the photograph. Furthermore, when a photograph of an adult monkey signalled attention to one location, but the toy appeared at the opposite (incompatible) location, subjects re-inspected the monkey photographs more often than when the toy appeared at the compatible location, suggesting a violation of expectancy. This effect was not the case if the photograph was of an immature animal. Our results show that attention-following was not limited to simple reflexive orienting by the monkeys, and that monkeys perceived a relationship existing between agent and object of attention.Gestural communication in orangutans (Pongo pygmaeus and Pongo abelii) : a cognitive approachCartmill, Erica A.https://hdl.handle.net/10023/6342019-07-01T10:14:37Z2009-06-01T00:00:00ZWhile most human language is expressed verbally, the gestures produced concurrent to speech provide additional information, help listeners interpret meaning, and provide insight into the cognitive processes of the speaker. Several theories have suggested that gesture played an important, possibly central, role in the evolution of language. Great apes have been shown to use gestures flexibly in different situations and to modify their gestures in response to changing contexts. However, it has not previously been determined whether ape gestures are defined by structural variables, carry meaning, are used to intentionally communicate specific information to others, or can be used strategically to overcome miscommunication.
To investigate these questions, I studied three captive populations of orangutans (Pongo pygmaeus and P. abelii) in European zoos for 10 months. Sixty-four different gestures, defined through similarities in structure and use, were included in the study after meeting strict criteria for intentional usage. More than half of the gesture types were found to coincide frequently with specific goals of signallers, and were accordingly identified as having meanings. Both structural and social variables were found to determine gesture meaning. The recipient’s gaze in both the present and the past, and the recipient’s apparent understanding of the signaller’s gestures, affected the strategies orangutans employed in their attempts to communicate when confronted with different types of communicative failure (e.g. not seeing, ignoring, misunderstanding, or rejecting a gesture). Maternal influence affected the object-directed behaviour and gestures of infants, who shared more gestures with their mothers than with other females. These findings demonstrate that gesture can be used as a medium to investigate not only the communication but also the cognition of great apes, and indicate that orangutans are more sensitive to the perceptions and knowledge states of others than previously thought.
2009-06-01T00:00:00ZCartmill, Erica A.While most human language is expressed verbally, the gestures produced concurrent to speech provide additional information, help listeners interpret meaning, and provide insight into the cognitive processes of the speaker. Several theories have suggested that gesture played an important, possibly central, role in the evolution of language. Great apes have been shown to use gestures flexibly in different situations and to modify their gestures in response to changing contexts. However, it has not previously been determined whether ape gestures are defined by structural variables, carry meaning, are used to intentionally communicate specific information to others, or can be used strategically to overcome miscommunication.
To investigate these questions, I studied three captive populations of orangutans (Pongo pygmaeus and P. abelii) in European zoos for 10 months. Sixty-four different gestures, defined through similarities in structure and use, were included in the study after meeting strict criteria for intentional usage. More than half of the gesture types were found to coincide frequently with specific goals of signallers, and were accordingly identified as having meanings. Both structural and social variables were found to determine gesture meaning. The recipient’s gaze in both the present and the past, and the recipient’s apparent understanding of the signaller’s gestures, affected the strategies orangutans employed in their attempts to communicate when confronted with different types of communicative failure (e.g. not seeing, ignoring, misunderstanding, or rejecting a gesture). Maternal influence affected the object-directed behaviour and gestures of infants, who shared more gestures with their mothers than with other females. These findings demonstrate that gesture can be used as a medium to investigate not only the communication but also the cognition of great apes, and indicate that orangutans are more sensitive to the perceptions and knowledge states of others than previously thought.Is it through emotion that we know ourselves? : a psychophysiological investigation into self-reference and emotional valenceWatson, Lynn A. S.https://hdl.handle.net/10023/5352020-03-03T10:33:39Z2008-06-26T00:00:00ZThe aims of the present thesis were two fold. The first aim was to investigate
the relationship between self-referential and emotional processing. The second aim
was to investigate the extent to which self-referential processing is altered as a function
of mood. In order to address these two aims, a variety of behavioural and physiological
measures were recorded and a new methodology was employed in the following
experimental chapters.
The aim of experiment one was to investigate how non-dysphoric and dysphoric
individuals evaluate the emotional valence and self-referential content of word stimuli
at a behavioural level. A self-positivity bias was identified in non-dysphoric
individuals, positive words were rated as self-referential and negative words were rated
as non-self-referential. Compared to non-dysphoric individuals, dysphoric individualsâ
evaluations of self-reference but not emotional valence were altered. Event-related
potentials (ERPs) were employed in experiment two to investigate self-referential
processing at a neural level. A two stage model of processing was identified in which,
an evaluation of emotional valence was found to occur prior to an interaction between
self-reference and emotional valence. A self-positivity bias was identified in the ERP
component known as the N400. ERP waves were more negative going to self negative
and non-self-positive words when compared to self-positive and non-self-negative
words. This bias was explained in terms of the semantic mismatch hypothesis. The
aim of experiment three was to investigate how the neural processing of self-referential
and emotional information is altered as a function of mood. Differences between nondysphoric
and dysphoric individuals were identified during the early stages of
ii
processing in an emotion task. Between group differences were identified during the
later stages of processing in a self-reference task, around 400 ms. Skin conductance
and heart rate were employed in experiment four to examine autonomic responses
during self-referential and emotional processing in healthy individuals. Both decision-making
tasks were found to elicit similar physiological responses. These findings were
taken to suggest that a large component of self-referential processing involves the
processing of emotional information. Finally, the aim of experiment five was to
investigate if person-referent processing was altered during the experience of a negative
mood. The behavioural and neural responses of non-dysphoric and dysphoric
individuals were compared across self-referent and other-referent decision-making
tasks. Between group differences were specific to the self-reference task at the
behavioural level. However, group differences were identified in both the self-referent
and other-referent tasks at the neural level. The results provide partial support for the
hypothesis that negative mood is associated with specific impairments in self-referential
processing.
Overall the results of the present thesis illustrate that the processing of
emotional information plays a large role in self-referential decision-making.
Furthermore, the N400 was found be involved in this type of decision-making at the
semantic level. Negative mood was associated with greater changes in self-referential
processing than in other forms of emotional or person-referent processing. In the final
chapter, a two stage model is proposed to account for self-referential processing. The
implications of this model are discussed in terms of two macro-cognitive theories,
interacting cognitive subsystems (ICS) and SPAARs. Finally, the limitations and
future directions for developing this line of research are outlined.
2008-06-26T00:00:00ZWatson, Lynn A. S.The aims of the present thesis were two fold. The first aim was to investigate
the relationship between self-referential and emotional processing. The second aim
was to investigate the extent to which self-referential processing is altered as a function
of mood. In order to address these two aims, a variety of behavioural and physiological
measures were recorded and a new methodology was employed in the following
experimental chapters.
The aim of experiment one was to investigate how non-dysphoric and dysphoric
individuals evaluate the emotional valence and self-referential content of word stimuli
at a behavioural level. A self-positivity bias was identified in non-dysphoric
individuals, positive words were rated as self-referential and negative words were rated
as non-self-referential. Compared to non-dysphoric individuals, dysphoric individualsâ
evaluations of self-reference but not emotional valence were altered. Event-related
potentials (ERPs) were employed in experiment two to investigate self-referential
processing at a neural level. A two stage model of processing was identified in which,
an evaluation of emotional valence was found to occur prior to an interaction between
self-reference and emotional valence. A self-positivity bias was identified in the ERP
component known as the N400. ERP waves were more negative going to self negative
and non-self-positive words when compared to self-positive and non-self-negative
words. This bias was explained in terms of the semantic mismatch hypothesis. The
aim of experiment three was to investigate how the neural processing of self-referential
and emotional information is altered as a function of mood. Differences between nondysphoric
and dysphoric individuals were identified during the early stages of
ii
processing in an emotion task. Between group differences were identified during the
later stages of processing in a self-reference task, around 400 ms. Skin conductance
and heart rate were employed in experiment four to examine autonomic responses
during self-referential and emotional processing in healthy individuals. Both decision-making
tasks were found to elicit similar physiological responses. These findings were
taken to suggest that a large component of self-referential processing involves the
processing of emotional information. Finally, the aim of experiment five was to
investigate if person-referent processing was altered during the experience of a negative
mood. The behavioural and neural responses of non-dysphoric and dysphoric
individuals were compared across self-referent and other-referent decision-making
tasks. Between group differences were specific to the self-reference task at the
behavioural level. However, group differences were identified in both the self-referent
and other-referent tasks at the neural level. The results provide partial support for the
hypothesis that negative mood is associated with specific impairments in self-referential
processing.
Overall the results of the present thesis illustrate that the processing of
emotional information plays a large role in self-referential decision-making.
Furthermore, the N400 was found be involved in this type of decision-making at the
semantic level. Negative mood was associated with greater changes in self-referential
processing than in other forms of emotional or person-referent processing. In the final
chapter, a two stage model is proposed to account for self-referential processing. The
implications of this model are discussed in terms of two macro-cognitive theories,
interacting cognitive subsystems (ICS) and SPAARs. Finally, the limitations and
future directions for developing this line of research are outlined.Immediate early gene expression in the mesopontine tegmentum and midbrain after acute or chronic nicotine administrationPorter, Ailsahttps://hdl.handle.net/10023/5072020-02-20T11:59:24Z2008-06-01T00:00:00ZThe reinforcing properties of nicotine depend partly on cholinergic projections from the pedunculopontine tegmental (PPTg) and laterodorsal tegmental (LDTg) nuclei to midbrain dopamine neurons in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). Neuronal activation was investigated using Fos expression in these areas following acute (0, 0.1, 0.4, 0.8mg/kg) or chronic systemic nicotine (0, 0.1, 0.4, 0.8, 1.0mg/kg given once per day for 5 days). We also examined co-localization of Fos expression in bNOS and TH positive neurons to determine what populations of neurons were activated by nicotine.
Acute nicotine resulted in dose related Fos expression, with the biggest increase seen after 0.4mg/kg nicotine, but no co-localization occurred with bNOS in the PPTg/LDTg. Surprisingly, nicotine also failed to activate midbrain dopamine neurons. After animals were sensitized to nicotine there was a similar dose response curve in Fos expression, but the biggest increase was seen after 0.8mg/kg nicotine. Chronic nicotine, like acute, also preferentially activated non-cholinergic neurons in the LDTg and PPTg and non-dopamine neurons in the SNc and VTA.
Further experiments looked at the mechanisms of Fos expression after nicotine administration. Fos expression in the LDTg/PPTg and SNc/VTA was suppressed after d-amphetamine, despite an increase in locomotor activity, suggesting that the increased Fos expression after chronic nicotine was not simply due to the locomotor activating effects of sensitized nicotine. Blocking autoreceptors in the dopaminergic midbrain by haloperidol pre-treatment did not increase Fos expression in dopamine neurons indicating that the inhibitory mechanism was not dependent on local autoreceptors. Novel methods of visualising and lesioning GABA neurons in the mesopontine tegmentum and midbrain were also examined.
The data suggest that the mechanisms by which dopamine is involved in the pharmacological actions of passively administered nicotine are more complex than was first thought and that the role of non-dopamine neurons in the VTA (possibly GABA or glutamate containing) are also important.
2008-06-01T00:00:00ZPorter, AilsaThe reinforcing properties of nicotine depend partly on cholinergic projections from the pedunculopontine tegmental (PPTg) and laterodorsal tegmental (LDTg) nuclei to midbrain dopamine neurons in the ventral tegmental area (VTA) and substantia nigra pars compacta (SNc). Neuronal activation was investigated using Fos expression in these areas following acute (0, 0.1, 0.4, 0.8mg/kg) or chronic systemic nicotine (0, 0.1, 0.4, 0.8, 1.0mg/kg given once per day for 5 days). We also examined co-localization of Fos expression in bNOS and TH positive neurons to determine what populations of neurons were activated by nicotine.
Acute nicotine resulted in dose related Fos expression, with the biggest increase seen after 0.4mg/kg nicotine, but no co-localization occurred with bNOS in the PPTg/LDTg. Surprisingly, nicotine also failed to activate midbrain dopamine neurons. After animals were sensitized to nicotine there was a similar dose response curve in Fos expression, but the biggest increase was seen after 0.8mg/kg nicotine. Chronic nicotine, like acute, also preferentially activated non-cholinergic neurons in the LDTg and PPTg and non-dopamine neurons in the SNc and VTA.
Further experiments looked at the mechanisms of Fos expression after nicotine administration. Fos expression in the LDTg/PPTg and SNc/VTA was suppressed after d-amphetamine, despite an increase in locomotor activity, suggesting that the increased Fos expression after chronic nicotine was not simply due to the locomotor activating effects of sensitized nicotine. Blocking autoreceptors in the dopaminergic midbrain by haloperidol pre-treatment did not increase Fos expression in dopamine neurons indicating that the inhibitory mechanism was not dependent on local autoreceptors. Novel methods of visualising and lesioning GABA neurons in the mesopontine tegmentum and midbrain were also examined.
The data suggest that the mechanisms by which dopamine is involved in the pharmacological actions of passively administered nicotine are more complex than was first thought and that the role of non-dopamine neurons in the VTA (possibly GABA or glutamate containing) are also important.Sparse codingFoldiak, PEndres, D Mhttps://hdl.handle.net/10023/4942019-04-01T10:39:23Z2008-01-01T00:00:00ZMammalian brains consist of billions of neurons, each capable of independent electrical activity. Information in the brain is represented by the pattern of activation of this large neural population, forming a neural code. The neural code defines what pattern of neural activity corresponds to each represented information item. In the sensory system, such items may indicate the presence of a stimulus object or the value of some stimulus parameter, assuming that each time this item is represented the neural activity pattern will be the same or at least similar. One important and relatively simple property of this code is the fraction of neurons that are strongly active at any one time. For a set of N binary neurons (which can either be 'active' or 'inactive'), the average (i.e., expected value) of this fraction across all information items is the sparseness of the code. This average fraction can vary from close to 0 to about 1/2. Average fractions above 1/2 can always be decreased below 1/2 without loss of information by replacing each active neuron with an inactive one, and vice versa. Sparse coding is the representation of items by the strong activation of a relatively small set of neurons. For each stimulus, this is a different subset of all available neurons.
The(frequently updated) original version is avalable at http://www.scholarpedia.org/article/Sparse_coding
2008-01-01T00:00:00ZFoldiak, PEndres, D MMammalian brains consist of billions of neurons, each capable of independent electrical activity. Information in the brain is represented by the pattern of activation of this large neural population, forming a neural code. The neural code defines what pattern of neural activity corresponds to each represented information item. In the sensory system, such items may indicate the presence of a stimulus object or the value of some stimulus parameter, assuming that each time this item is represented the neural activity pattern will be the same or at least similar. One important and relatively simple property of this code is the fraction of neurons that are strongly active at any one time. For a set of N binary neurons (which can either be 'active' or 'inactive'), the average (i.e., expected value) of this fraction across all information items is the sparseness of the code. This average fraction can vary from close to 0 to about 1/2. Average fractions above 1/2 can always be decreased below 1/2 without loss of information by replacing each active neuron with an inactive one, and vice versa. Sparse coding is the representation of items by the strong activation of a relatively small set of neurons. For each stimulus, this is a different subset of all available neurons.Bayesian binning beats approximate alternatives: estimating peri-stimulus time histogramsEndres, D MOram, M WSchindelin, J.E.Foldiak, Phttps://hdl.handle.net/10023/4732019-04-01T10:36:27Z2008-01-01T00:00:00ZThe peristimulus time histogram (PSTH) and its more continuous cousin, the spike density function (SDF) are staples in the analytic toolkit of neurophysiologists. The former is usually obtained by binning spike trains, whereas the standard method for the latter is smoothing with a Gaussian kernel. Selection of a bin width or a kernel size is often done in an relatively arbitrary fashion, even though there have been recent attempts to remedy this situation. We develop an exact Bayesian, generative model approach to estimating PSTHs and demonstate its superiority to competing methods. Further advantages of our scheme include automatic complexity control and error bars on its predictions.
2008-01-01T00:00:00ZEndres, D MOram, M WSchindelin, J.E.Foldiak, PThe peristimulus time histogram (PSTH) and its more continuous cousin, the spike density function (SDF) are staples in the analytic toolkit of neurophysiologists. The former is usually obtained by binning spike trains, whereas the standard method for the latter is smoothing with a Gaussian kernel. Selection of a bin width or a kernel size is often done in an relatively arbitrary fashion, even though there have been recent attempts to remedy this situation. We develop an exact Bayesian, generative model approach to estimating PSTHs and demonstate its superiority to competing methods. Further advantages of our scheme include automatic complexity control and error bars on its predictions.Dissection of observational learning among chimpanzees (Pan troglodytes) and children (Homo sapiens)Hopper, Lydia Merielhttps://hdl.handle.net/10023/4362019-07-01T10:11:45Z2008-01-01T00:00:00ZIn the wild, a variety of inter-group behavioural differences have been reported for chimpanzees (Pan troglodytes) and it has been suggested that these may have resulted from social learning. To determine whether chimpanzees show the necessary propensity for social learning, groups of captive chimpanzees were tested in a series of experiments involving the use of two-action and bidirectional apparatuses. For comparison, and to shed light on any contrasts between our own and chimpanzee learning strategies, similar tests were also conducted with children (Homo sapiens) to ascertain the nature of their observational learning when watching conspecifics. Through the use of open diffusion and diffusion chain techniques, it was shown that both species learnt how to operate different foraging devices from observing an expert conspecific and this learning was strong enough for the generation of behavioural traditions which passed along multiple test ‘generations’. Additionally, ghost conditions were used to distinguish imitative and emulative learning by both species. With one of the two test devices used (the Slide-box) the first evidence for emulation learning by chimpanzees, through the use of a ghost condition, was shown. Children in this condition also showed apparent emulation; a contrast to previous research which has concluded that children tend to rely on imitation. Additionally, to test its potential for use in future social learning experiments, the ability of chimpanzees to learn from video-footage of an unknown conspecific was tested. It was found that the chimpanzees not only learnt how to operate two devices from observing this footage but also used the same alternative method used by the model chimpanzee.
2008-01-01T00:00:00ZHopper, Lydia MerielIn the wild, a variety of inter-group behavioural differences have been reported for chimpanzees (Pan troglodytes) and it has been suggested that these may have resulted from social learning. To determine whether chimpanzees show the necessary propensity for social learning, groups of captive chimpanzees were tested in a series of experiments involving the use of two-action and bidirectional apparatuses. For comparison, and to shed light on any contrasts between our own and chimpanzee learning strategies, similar tests were also conducted with children (Homo sapiens) to ascertain the nature of their observational learning when watching conspecifics. Through the use of open diffusion and diffusion chain techniques, it was shown that both species learnt how to operate different foraging devices from observing an expert conspecific and this learning was strong enough for the generation of behavioural traditions which passed along multiple test ‘generations’. Additionally, ghost conditions were used to distinguish imitative and emulative learning by both species. With one of the two test devices used (the Slide-box) the first evidence for emulation learning by chimpanzees, through the use of a ghost condition, was shown. Children in this condition also showed apparent emulation; a contrast to previous research which has concluded that children tend to rely on imitation. Additionally, to test its potential for use in future social learning experiments, the ability of chimpanzees to learn from video-footage of an unknown conspecific was tested. It was found that the chimpanzees not only learnt how to operate two devices from observing this footage but also used the same alternative method used by the model chimpanzee.Behavioural investigation of the role of caudal thalamic reticular nucleus in attentionPetrof, Iraklishttps://hdl.handle.net/10023/3732019-07-01T10:19:57Z2007-11-01T00:00:00ZThe thalamic reticular nucleus (TRN), and especially its caudal, sensory-related, half (cTRN), has been hypothesised for years to be at the very heart of thalamic sensory processing modulation, and attentional processes in particular. Very limited behavioural evidence is available, nonetheless, in support of such a functional attribution. In this thesis we carried out a series of investigations, combining immunocytochemical and lesion techniques with tests of behaviour, in order to examine the potential role of cTRN in attention and identify the attentional processes, if any, that it is more likely to contribute to.
In chapter II, we looked at the Fos activation levels within modality-specific sectors of cTRN following attentive behaviours to stimulation of different modalities. We observed a selective activation of the visual sector of cTRN in visually attentive animals but not in tactilely attentive, yet visually stimulated, animals, thus demonstrating an involvement of that area in processes of visual attention.
In chapter III we looked at the role of cTRN in cross-modal expressions of divided attention. We found that its removal, through neurotoxic lesioning, did not result in any behavioural costs with regard to the division of attention. Detriments in response accuracy, however, suggested that cTRN may be involved in stimulus processing enhancement operations, unrelated with the division of attention.
Finally, in chapters IV and V, we looked at the effects of lesions of the visual sector of cTRN (TRNvis) on the ability to orient attention covertly within visual space. We found that the removal of TRNvis did not affect visual covert orienting behaviour, both when this is triggered by exogenous and endogenous means. Overall our results suggest that even though cTRN appears to be involved in some aspects of attention, it does not represent a necessary structure for the generation and operation of certain other forms of attention.
2007-11-01T00:00:00ZPetrof, IraklisThe thalamic reticular nucleus (TRN), and especially its caudal, sensory-related, half (cTRN), has been hypothesised for years to be at the very heart of thalamic sensory processing modulation, and attentional processes in particular. Very limited behavioural evidence is available, nonetheless, in support of such a functional attribution. In this thesis we carried out a series of investigations, combining immunocytochemical and lesion techniques with tests of behaviour, in order to examine the potential role of cTRN in attention and identify the attentional processes, if any, that it is more likely to contribute to.
In chapter II, we looked at the Fos activation levels within modality-specific sectors of cTRN following attentive behaviours to stimulation of different modalities. We observed a selective activation of the visual sector of cTRN in visually attentive animals but not in tactilely attentive, yet visually stimulated, animals, thus demonstrating an involvement of that area in processes of visual attention.
In chapter III we looked at the role of cTRN in cross-modal expressions of divided attention. We found that its removal, through neurotoxic lesioning, did not result in any behavioural costs with regard to the division of attention. Detriments in response accuracy, however, suggested that cTRN may be involved in stimulus processing enhancement operations, unrelated with the division of attention.
Finally, in chapters IV and V, we looked at the effects of lesions of the visual sector of cTRN (TRNvis) on the ability to orient attention covertly within visual space. We found that the removal of TRNvis did not affect visual covert orienting behaviour, both when this is triggered by exogenous and endogenous means. Overall our results suggest that even though cTRN appears to be involved in some aspects of attention, it does not represent a necessary structure for the generation and operation of certain other forms of attention.Human use of horizontal disparity for perception and visuomotor controlScarfe, Peterhttps://hdl.handle.net/10023/3682019-07-01T10:14:18Z2007-11-30T00:00:00ZOur eyes are horizontally separated in the head by approximately 6.5cm. As a result of this separation there are subtle differences in the position of corresponding image points within the two eyes. The horizontal component of this binocular positional difference is termed horizontal disparity. Horizontal disparity is an important visual cue as once scaled with an estimate of the viewing distance, it can theoretically provide full metric information about the structure of the world. This thesis will address the issue of how binocular visual cues are used by the human visual system for the estimation of three-dimensional (3-D) shape for perception and visuomotor control. The research presented is particularly focused on understanding why biases in the perception of 3-D shape from binocular cues are found, their importance for perception and visuomotor control and how these biases may be overcome by combining binocular cues with other sources of visual information.
2007-11-30T00:00:00ZScarfe, PeterOur eyes are horizontally separated in the head by approximately 6.5cm. As a result of this separation there are subtle differences in the position of corresponding image points within the two eyes. The horizontal component of this binocular positional difference is termed horizontal disparity. Horizontal disparity is an important visual cue as once scaled with an estimate of the viewing distance, it can theoretically provide full metric information about the structure of the world. This thesis will address the issue of how binocular visual cues are used by the human visual system for the estimation of three-dimensional (3-D) shape for perception and visuomotor control. The research presented is particularly focused on understanding why biases in the perception of 3-D shape from binocular cues are found, their importance for perception and visuomotor control and how these biases may be overcome by combining binocular cues with other sources of visual information.The effect of rumination on social problem-solving and autobiographical memory retrieval in depression : a cross-cultural perspectiveKao, Chih-Meihttps://hdl.handle.net/10023/3442019-04-01T10:40:22Z2007-02-01T00:00:00ZPrevious research has indicated that depression and thinking style (rumination versus distraction) interact to influence cognitive processing. Depressed ruminators produce more categoric autobiographical memories (AM) (i.e., a summary of repeated memories), and also demonstrate poorer SPS performance than depressed distracters and matched controls. The quality of AM retrieval during SPS is also related to the effectiveness of SPS solutions such that categoric AM retrieval during SPS contributes to poorer SPS. Therefore, the first aim of this thesis was to extend previous work by further investigating how an induced rumination/distraction influences subsequent AM retrieval during SPS and SPS performance. The first two studies examined how thinking style influences SPS and AM retrieval during SPS in a dysphoric (study 1) versus clinically depressed sample (study 2). The results indicated that rumination has a detrimental effect on SPS in both dysphoric and clinically depressed samples, with more pronounced effects in the clinical group. Rumination also appeared to influence AM retrieval during SPS for the clinically depressed group but not the dysphoric group. Moreover, in both samples, SPS performance was associated with the type of AM retrieval involved in the SPS process. As most studies investigating cognitive processes in depression have focused on Western people, a second aim of this thesis was to examine the association between thinking style, AM
retrieval and SPS performance in depression from a cross-cultural perspective. The first cross-cultural study (Study 3) looked at AM retrieval on the AMT cueing task and the second cross-cultural study (Study 4) investigated whether these associations between thinking style, SPS and AM retrieval would vary across different cultures. Culture interacted with depression to influence AM retrieval on the AMT cueing task. However study 4 demonstrated that there seemed to be no interaction between culture, rumination and depression on SPS performance and AM retrieval during SPS.
2007-02-01T00:00:00ZKao, Chih-MeiPrevious research has indicated that depression and thinking style (rumination versus distraction) interact to influence cognitive processing. Depressed ruminators produce more categoric autobiographical memories (AM) (i.e., a summary of repeated memories), and also demonstrate poorer SPS performance than depressed distracters and matched controls. The quality of AM retrieval during SPS is also related to the effectiveness of SPS solutions such that categoric AM retrieval during SPS contributes to poorer SPS. Therefore, the first aim of this thesis was to extend previous work by further investigating how an induced rumination/distraction influences subsequent AM retrieval during SPS and SPS performance. The first two studies examined how thinking style influences SPS and AM retrieval during SPS in a dysphoric (study 1) versus clinically depressed sample (study 2). The results indicated that rumination has a detrimental effect on SPS in both dysphoric and clinically depressed samples, with more pronounced effects in the clinical group. Rumination also appeared to influence AM retrieval during SPS for the clinically depressed group but not the dysphoric group. Moreover, in both samples, SPS performance was associated with the type of AM retrieval involved in the SPS process. As most studies investigating cognitive processes in depression have focused on Western people, a second aim of this thesis was to examine the association between thinking style, AM
retrieval and SPS performance in depression from a cross-cultural perspective. The first cross-cultural study (Study 3) looked at AM retrieval on the AMT cueing task and the second cross-cultural study (Study 4) investigated whether these associations between thinking style, SPS and AM retrieval would vary across different cultures. Culture interacted with depression to influence AM retrieval on the AMT cueing task. However study 4 demonstrated that there seemed to be no interaction between culture, rumination and depression on SPS performance and AM retrieval during SPS.The effects of female status on sex differentiated mate preferencesMoore, Fhionna R.https://hdl.handle.net/10023/3322019-07-01T10:19:13Z2007-01-01T00:00:00ZMate preferences provide an opportunity to explore the validity of evolutionary
and social role origin theories of sex differences in human behaviour. In
evolutionary models, preferences are sex-specific adaptive responses to
constraints to reproductive success. In social role models, sex differences arise
from the allocation of men and women to different gender roles. I explored the
effects of the status of women on preferences to assess the validity of the origin
theories. I developed an adequate measure of female status (i.e. resource
control), and explored its effects on female preferences in an online survey
(Chapter 3), a mail-shot survey (Chapter 4), and a sample of non-industrial
societies (Chapter 5). Results implicated a role of constraints on women in the
expression of female-typical preferences. In an experimental manipulation of
female perceptions of their status, results enabled greater confidence in the
attribution of causal direction to relationships (Chapter 6). In Chapter 7, I
explored the conditions under which the relationships of interest occurred. In
Chapter 8, to further explore the origin models I investigated the effects of
resource control on the magnitudes of sex differences in preferences. In Chapter
9, I explored relationships between a characteristic more closely related to the
male gender role (i.e. apparent intelligence) and femininity in female faces.
Women who were considered to look more intelligent were perceived as less
feminine. In Chapter 10, I investigated the effects of reproductive strategy on
mate preferences. Results were consistent with evolutionary models of
behaviour. I argue that “status” is a multidimensional construct, and that its
effects on mate preferences are complex, that while results were generally more
consistent with an evolutionary than the biosocial model, integration of models
would provide greater insight into human mate preferences.
2007-01-01T00:00:00ZMoore, Fhionna R.Mate preferences provide an opportunity to explore the validity of evolutionary
and social role origin theories of sex differences in human behaviour. In
evolutionary models, preferences are sex-specific adaptive responses to
constraints to reproductive success. In social role models, sex differences arise
from the allocation of men and women to different gender roles. I explored the
effects of the status of women on preferences to assess the validity of the origin
theories. I developed an adequate measure of female status (i.e. resource
control), and explored its effects on female preferences in an online survey
(Chapter 3), a mail-shot survey (Chapter 4), and a sample of non-industrial
societies (Chapter 5). Results implicated a role of constraints on women in the
expression of female-typical preferences. In an experimental manipulation of
female perceptions of their status, results enabled greater confidence in the
attribution of causal direction to relationships (Chapter 6). In Chapter 7, I
explored the conditions under which the relationships of interest occurred. In
Chapter 8, to further explore the origin models I investigated the effects of
resource control on the magnitudes of sex differences in preferences. In Chapter
9, I explored relationships between a characteristic more closely related to the
male gender role (i.e. apparent intelligence) and femininity in female faces.
Women who were considered to look more intelligent were perceived as less
feminine. In Chapter 10, I investigated the effects of reproductive strategy on
mate preferences. Results were consistent with evolutionary models of
behaviour. I argue that “status” is a multidimensional construct, and that its
effects on mate preferences are complex, that while results were generally more
consistent with an evolutionary than the biosocial model, integration of models
would provide greater insight into human mate preferences.Bayesian and information-theoretic tools for neuroscienceEndres, Dominik M.https://hdl.handle.net/10023/1622019-07-01T10:15:03Z2006-11-30T00:00:00ZThe overarching purpose of the studies presented in this report is the exploration of the uses of information theory and Bayesian inference applied to neural codes. Two approaches were taken: Starting from first principles, a coding mechanism is proposed, the results are compared to a biological neural code. Secondly, tools from information theory are used to measure the information contained in a biological neural code.
Chapter 3: The REC model proposed by Harpur and Prager codes inputs into a sparse, factorial representation, maintaining reconstruction accuracy. Here I propose a modification of the REC model to determine the optimal network dimensionality. The resulting code for unfiltered natural images is accurate, highly sparse and a large fraction of the code elements show localized features. Furthermore, I propose an activation algorithm for the network that is faster and more accurate than a gradient descent based activation method. Moreover, it is demonstrated that asymmetric noise promotes sparseness.
Chapter 4: A fast, exact alternative to Bayesian classification is introduced. Computational time is quadratic in both the number of observed data points and the number of degrees of freedom of the underlying model. As an example application, responses of single neurons from high-level visual cortex (area STSa) to rapid sequences of complex visual stimuli are analyzed.
Chapter 5: I present an exact Bayesian treatment of a simple, yet sufficiently general probability distribution model. The model complexity, exact values of the expectations of entropies and their variances can be computed with polynomial effort given the data. The expectation of the mutual information becomes thus available, too, and a strict upper bound on its variance. The resulting algorithm is first tested on artificial data. To that end, an information theoretic similarity measure is derived. Second, the algorithm is demonstrated to be useful in neuroscience by studying the information content of the neural responses analyzed in the previous chapter. It is shown that the information throughput of STS neurons is maximized for stimulus durations of approx. 60ms.
2006-11-30T00:00:00ZEndres, Dominik M.The overarching purpose of the studies presented in this report is the exploration of the uses of information theory and Bayesian inference applied to neural codes. Two approaches were taken: Starting from first principles, a coding mechanism is proposed, the results are compared to a biological neural code. Secondly, tools from information theory are used to measure the information contained in a biological neural code.
Chapter 3: The REC model proposed by Harpur and Prager codes inputs into a sparse, factorial representation, maintaining reconstruction accuracy. Here I propose a modification of the REC model to determine the optimal network dimensionality. The resulting code for unfiltered natural images is accurate, highly sparse and a large fraction of the code elements show localized features. Furthermore, I propose an activation algorithm for the network that is faster and more accurate than a gradient descent based activation method. Moreover, it is demonstrated that asymmetric noise promotes sparseness.
Chapter 4: A fast, exact alternative to Bayesian classification is introduced. Computational time is quadratic in both the number of observed data points and the number of degrees of freedom of the underlying model. As an example application, responses of single neurons from high-level visual cortex (area STSa) to rapid sequences of complex visual stimuli are analyzed.
Chapter 5: I present an exact Bayesian treatment of a simple, yet sufficiently general probability distribution model. The model complexity, exact values of the expectations of entropies and their variances can be computed with polynomial effort given the data. The expectation of the mutual information becomes thus available, too, and a strict upper bound on its variance. The resulting algorithm is first tested on artificial data. To that end, an information theoretic similarity measure is derived. Second, the algorithm is demonstrated to be useful in neuroscience by studying the information content of the neural responses analyzed in the previous chapter. It is shown that the information throughput of STS neurons is maximized for stimulus durations of approx. 60ms.