Psychology & Neuroscience Research
https://hdl.handle.net/10023/131
2024-03-28T18:33:22ZThe resilience paradox : flooding experience, coping and climate change mitigation intentions
https://hdl.handle.net/10023/17064
Climate 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.Monkeys (Sapajus apella and Macaca tonkeana) and great apes (Gorilla gorilla, Pongo pygmaeus, Pongo abelii, Pan paniscus and Pan troglodytes) play for the highest bid
https://hdl.handle.net/10023/16092
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.
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.Behavioral conservatism is linked to complexity of behavior in chimpanzees (Pan troglodytes) : implications for cognition and cumulative culture
https://hdl.handle.net/10023/15610
Cumulative 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.Sharing and fairness in development
https://hdl.handle.net/10023/13834
2016-12-07T00:00:00ZRochat, PhilippeRobbins, ErinNo evidence for contagious yawning in lemurs
https://hdl.handle.net/10023/13022
Among 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.Behavioral, ecological, and evolutionary aspects of meat-eating by Sumatran orangutans (Pongo abelii)
https://hdl.handle.net/10023/12455
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.
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.Organic light-emitting diodes for optogenetic stimulation of Drosophila larvae
https://hdl.handle.net/10023/9861
Optogenetics 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.Computerized self-administered measures of mood and appetite for older adults : the Novel Assessment of Nutrition and Ageing toolkit
https://hdl.handle.net/10023/9351
The "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.Light activated escape circuits : a behavior and neurophysiology lab module using Drosophila optogenetics
https://hdl.handle.net/10023/8256
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.
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.Data underpinning: Perception of Health from Facial Cues
https://hdl.handle.net/10023/7924
Dataset 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.Stimulation of glia reveals modulation of mammalian spinal motor networks by adenosine
https://hdl.handle.net/10023/7234
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.
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.The goal trumps the means : highlighting goals is more beneficial than highlighting means in means-end training
https://hdl.handle.net/10023/6183
Means-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.A genetic algorithm for face fitting
https://hdl.handle.net/10023/5443
Accurate 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 regions
https://hdl.handle.net/10023/5349
Natural 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 Tasks
https://hdl.handle.net/10023/5066
Research 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 labs
https://hdl.handle.net/10023/5038
Neuroscience 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.Evaluating multicenter DTI data in Huntington's disease on site specific effects : an ex post facto approach
https://hdl.handle.net/10023/4789
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.
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 change
https://hdl.handle.net/10023/4572
In 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.Common HLA alleles associated with health, but not with facial attractiveness
https://hdl.handle.net/10023/4243
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.
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.Receiving post-conflict affiliation from the enemy's friend reconciles former opponents
https://hdl.handle.net/10023/4167
The 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 shape
https://hdl.handle.net/10023/3861
Although 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 maskingFemale putty-nosed monkeys use experimentally altered contextual information to disambiguate the cause of male alarm calls
https://hdl.handle.net/10023/3674
Many 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.Embodied metaphors and emotions in the moralization of restrained eating practices
https://hdl.handle.net/10023/3393
Moralization 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 reviewers
https://hdl.handle.net/10023/3380
Reducing 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 tool
https://hdl.handle.net/10023/3379
A 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 2007
https://hdl.handle.net/10023/3378
Purpose: 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.Learning to use illumination gradients as an unambiguous cue to three dimensional shape
https://hdl.handle.net/10023/3077
The 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 structures
https://hdl.handle.net/10023/3066
We 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.Interpreting the neural code with formal concept analysis
https://hdl.handle.net/10023/2991
We 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.Perception of relative depth interval : Systematic biases in perceived depth
https://hdl.handle.net/10023/2749
Given 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?
https://hdl.handle.net/10023/2746
There 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.Evidence for weak or linear conformity but not for hyper-conformity in an everyday social learning context
https://hdl.handle.net/10023/2555
Conformity 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.The maker not the tool: The cognitive significance of great ape manual skills
https://hdl.handle.net/10023/964
Tool-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 use
https://hdl.handle.net/10023/943
Tool 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.What do Diana monkeys know about the focus of attention of a conspecific?
https://hdl.handle.net/10023/660
Converging 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.Sparse coding
https://hdl.handle.net/10023/494
Mammalian 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 histograms
https://hdl.handle.net/10023/473
The 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.