Enhancing vision : a project on audio-visual decision-making, and a project on strengthening the visual system by short-term monocular patching

Abstract

Vision is important; two projects were conducted to explore the enhancement of vision (multisensory combination, novel procedure to improve visual functioning). In the first project, audition was combined with vision, to examine if the conjunction of two sensory modalities benefits sensory decision-making in the context of looming – a potentially dangerous motion requiring quick responses (e.g., Neuhoff, 2001). Four behavioural experiments were conducted, testing responses towards auditory, visual, or audio-visual motion-in-depth signals (i.e., looming or receding). From behavioural data, the decision-making mechanism was explored in two separate analyses: 1) a comparative approach (e.g., Innes & Otto, 2019) which compared empirical data to predictions made using probability summation (Raab, 1962), and 2) a computational modelling approach which determined the best permutation of an interactive probability summation rule (Otto & Mamassian, 2012) to fit the empirical data. Altogether, the first project revealed that decision-making had a speed benefit when auditory and visual signals were both present, compared to either modality alone, and this benefit could be explained by a probability summation rule with simple audio-visual interactions. Not found was evidence of especially quick processing uniquely towards audio-visual looming signals. For the second research direction, a pilot study was conducted to test a novel short-term monocular patching technique which purportedly induces eye dominance via latent neuroplasticity (e.g., Lunghi, Burr, & Morrone, 2011), with the idea that it could become a procedure for improving amblyopic visual functioning. In one small-scale experiment (n=4), a significant dominance effect on the patched eye was found, but the effect was short-lived. Two single-participant experiments indicated that patching durations should not be too short (10 minutes) and stereopsis sensitivity may slightly change after patching. This pilot study offered a preliminary look into patching effects, on the back of which further experiments are suggested.