Abstract
An influential proposal suggests that response priming is independent of awareness, depends on rapid feedforward sweep of visual information processing and depends on physical characteristics of the stimulus. We tested some of these hypotheses using a well-characterized flash-lag illusion: when a static stimulus is briefly presented in alignment with a moving stimulus, it is perceived as lagging behind it. This illusion is especially well suited for testing the hypotheses about priming for the following reasons: (1) it is very robust, (2) a large body of literature suggests that it is a high-level cognitive illusion and (3) it shows a strong dissociation between physical and perceived location. To prime for location, two horizontal bars, moving downwards or upwards were presented at the center of the display. A dot was then flashed between the bars. When bars were moving downwards, dot position was perceived above the bar and vice versa. Participants made speeded responses to targets, which followed primes and consisted of two static horizontal bars with dot positioned above or below them. If response priming is based on physical characteristics of the stimulus no priming would be expected because dot was spatially aligned with the bars. Our data revealed strong location priming, demonstrating that response priming depends on the percept and not the physical characteristics of the stimulus. There was no priming for moving bars alone. Because flash-lag illusion is considered high-level cognitive phenomenon, our data further suggest that visual system rapidly computes perceptual quality of the stimulus, which can affect even fast motor responses.
Meeting abstract presented at VSS 2018