Auditory-visual interactions in egocentric distance perception: Ventriloquism effect and aftereffect

Abstract

This study describes data on auditory-visual integration and visually-guided adaptation of auditory distance perception using the ventriloquism effect (VE) and ventriloquism aftereffect (VAE). In an experiment, participants judged egocentric distance of interleaved auditory or auditory-visual stimuli with the auditory component located from 0.7 to 2.04 m in front of listeners in a real reverberant environment. The visual component of auditory-visual stimuli was displaced 30% closer (V-closer), 30% farther (V-farther), or aligned (V-aligned) with respect to the auditory component. The VE and VAE were measured in auditory and auditory-visual trials, respectively. Both effects were approximately independent of target distance when expressed in logarithmic units. The VE strength, defined as a difference of V-misaligned and V-aligned response bias, was approximately 72% of the auditory-visual disparity regardless of the visual-displacement direction, while the VAE was stronger in the V-farther (44%) than the V-closer (31%) condition. The VAE persisted to post-adaptation auditory-only blocks of trials, although it was diminished. The rates of build-up/break-down of the VAE were asymmetrical, with slower adaptation in the V-closer condition. These results suggest that auditory-visual distance integration is independent of the direction of induced shift, while the re-calibration is stronger and faster when evoked by more distant visual stimuli.