Temporal Characteristics of the Ventriloquism Effect

Abstract

The perception of the spatial location of an auditory stimulus can be captured by a spatially disparate visual stimulus, a phenomenon known as the ventriloquism effect. Many studies have shown temporal and spatial dependency of this phenomenon but its temporal dynamics are not fully understood. In this study, we presented participants with a three-minute of audio-visual stimuli, consisting of a pair of light and sound noise with a spatial disparity of either 0, 5 or 10 degrees. Ten participants were instructed to observe the audio-visual stimuli, and to report their position consistency of stimuli by pushing one of two bottoms, which indicated "same" or "different" respectively. The time series reported were analyzed as perceptual transitions. The results showed that (1) the mean total duration of the "same location" response increased as the disparities between noise and light decreased, (2) the percept switched during the stimulus presentation in all disparity condition after initial build-up of perception of "same location", and (3) the mean transition times varied depending on the disparity condition. These results show that the ventriloquism effect varies with observation time, suggesting that audiovisual spatial integration have time-varying nature.