Crossmodal Contingent Aftereffect

Abstract

Sounds containing no motion or positional cues could induce illusory visual motion perception for static visual stimuli. Two identical visual stimuli placed side by side were presented in alternation producing apparent motion perception and each stimulus was accompanied by a tone burst of a specific and unique frequency. After prolonged exposure to the apparent motion, the tones acquired driving effects for motion perception; a visual stimulus blinking at a fixed location was perceived as lateral motion. The effect lasted at least for a few days and was only observed at the retinal position that was previously exposed to apparent motion with the tones. Furthermore, the effect was specific to ear and sound frequency presented in the exposure period. These results indicate that strong association between visual motion and sound sequence is easily formed within a short period and that very early stages of sensory processing might be responsive loci for the current phenomenon.