Abstract
The action-specific account of perception emphasizes the role of action in perception. The claim is that perceivers see the spatial layout of the environment in terms of their ability to perform the intended action. For example, when trying to block balls moving at various speeds, the balls look to be moving slower when the paddle used to block them is bigger and thus more effective at blocking (Witt & Sugovic, 2010, 2012, 2013). Yet to be determined is how action-based information exerts its influence. According to Bayesian theory, if two sources of information (such as action-based and visual information) are integrated, one source will exert a greater influence as uncertainty related to the other source increases. To test this, I took a novel approach by leveraging naturally-occurring individual differences in uncertainty. Participants (N = 62) attempted to block balls moving at various speeds with different sized paddles and estimated the speed of the ball. The point of subjective equality (PSE) was calculated for each paddle condition for each participant, and the difference in PSEs between the big and small paddles served as the measure of the action-specific effect. A bigger PSE difference score indicates a larger effect of paddle size on speed judgments. Just-noticeable differences (JNDs) were calculated for each participant across all trials and were used as a measure of uncertainty related to visual information. There was a positive correlation (r = .55, p <.001) between PSE difference scores and JNDs: as visual uncertainty increased, the action-specific effect also increased. According to Bayesian theory, this result suggests that action-related information is integrated directly with visual information.
Meeting abstract presented at VSS 2014