Multimodal apparent motion
Poster Presentation

Vanessa Harrar
Psychology York University

Rebecca Rebecca Winter
Psychology, York Univerisy

Laurence Harris
Centre for Vision Research

     Abstract ID Number: 85
     Full text: Not available
     Last modified: March 20, 2005

Abstract
Apparent motion has been demonstrated in the visual, auditory, and somatosensory domains, but it is less clear whether true apparent motion can be obtained between combinations of light, sound and touch. We presented subjects with unimodal and bimodal stimulus pairs of lights, sounds and touches (produced by mini solenoids) with a range of stimulus onset asynchronies (SOAs). Based on subjects’ forced-choice decisions between all combinations of SOAs, we determined the SOAs that evoked the most convincing unimodal and bimodal apparent motion. In another experiment, subjects made forced-choice decisions about the perceived direction of apparent motion. Psychometric functions provided the SOAs for apparent motion thresholds. We looked at how the optimal and threshold SOAs for apparent motion varied with distance between the pairs, and with duration and intensity of the stimuli. These variables are known to affect visual apparent motion, according to rules first outlined by Korte in 1915. By comparing the effect of these variables on unimodal and bimodal stimuli, we determined differences and similarities between unimodal and bimodal apparent motion. These data will be discussed in the context of emerging research revealing cross-modal influences on unimodal motion.