Abstract
Previous research has shown that people with only one eye have enhanced spatial vision implying sensory compensation for their loss of binocularity. We investigated whether the loss of one eye may lead to enhanced multisensory processing as a result of cross–modal sensory compensation. In Experiment 1, we measured speeded detection and discrimination of auditory, visual and audiovisual targets presented as a stream of paired familiar objects and sounds in people with one eye and controls viewing binocularly or with one eye patched. We found that all participants were equally able to detect the presence of auditory, visual or bimodal targets. However, when asked to discriminate between the unimodal and bimodal targets both control groups demonstrated preferential processing of visual over auditory information with the bimodal stimuli – the Colavita visual dominance effect. Moreover, participants with one eye, showed no Colavita effect and demonstrated equal preference of processing visual and auditory stimuli, suggesting better multisensory integration. In Experiment 2, we increased the temporal processing load by asking participants to detect and discriminate back–to–back stimulus repetitions in a stream of paired familiar objects and sounds expecting that auditory performance will dominate due to the tasks' temporal nature. Preliminary results indicate that all participants are equally able to detect the presence of auditory, visual or bimodal repetitions, however, when asked to discriminate between the unimodal and bimodal repetitions, the Colavita effect persists in both control groups. However, participants with one eye show no Colavita effect, and again demonstrate equal preference of processing visual and auditory stimuli. These results indicate that binocular viewing controls consistently demonstrate visual dominance, even when auditory dominance is expected but participants with one eye display equal auditory and visual processing, likely as a form of crossmodal adaptation and compensation for their loss of binocularity.
Canadian National Institute for the Blind.