Abstract
The interaction between action and visual perception is bi-directional: not only does vision guide most of our actions, but a growing number of studies suggest that our actions can in turn directly affect perceptual representations. The degree of action-perception congruency required to evoke such direct effects of action on perception is, however, debated. To address this issue, we used a continuous flash suppression (CFS) paradigm. A dynamic Mondrian pattern was presented to one eye, a horizontally drifting vertical grating to the other. In the main experimental condition ("coupled condition") the drift velocity of the grating was controlled by the observer through turning a manipulandum, such that the grating represented the front face of a virtual drum attached to the manipulandum. The control conditions included a visual-replay condition (no movement, but same visual stimulus) and a de-coupled motor condition (movement, but visual stimulus based on a different trial). In all conditions, observers were instructed to try and perceive the grating for as long as possible and to report by pressing a button whenever they achieved clear visibility. To overcome the obvious confound of non-veridical report, we validated report by measuring the observers' optokinetic nystagmus (OKN), which follows the grating if and only if it is visible. Our data show that the grating becomes visible more frequently and persists longer in the coupled condition than in the visual-only and de-coupled conditions. This shows that action exerts a direct effect on perception in CFS and that this effect requires visual-motor congruency. Intriguingly, congruency aids the appearance of the stimulus from suppression; that is, congruency may also reference action to a stimulus that is suppressed from awareness. Our results provide further evidence for shared representations between action and perception, and suggest that those may partially operate below visual awareness.
Meeting abstract presented at VSS 2016