Investigating the In-Between: Multisensory Integration ofAuditory and Visual Motion Streams

摘要

We investigated audiovisual interactions in motion perception by behavioral experiments testing both, theinfluence of visual stimuli on auditory apparent motion and the influence of auditory stimuli on visual ap-parent motion perception. A set of loudspeakers with an LED mounted in the middle of each speaker conewas arranged in a semicircle. Apparent motion streams were presented for each modality alone in the uni-modal conditions. In the bimodal conditions, stimuli of the second modality were added to fill the temporaland spatial gaps of the sampled trajectory of the reference stream. The participants' task was to observe thequasi-naturalistic stimulus sequences and to perform a standard classification. The addition of stimuli of thesecond modality indeed facilitated apparent motion perception. Bimodal presentation increased the uppertemporal interval up to which the stimuli could be separated in time while still being perceived as contin-uous motion. We interpret these results as evidence for an ecologically advantageous audiovisual motionintegration mechanism which operates beyond the constraints of strict spatiotemporal coincidence. Func-tional considerations suggest that this mechanism may represent an amodal stage suited for the processingof both unimodal and bimodal signals.