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

Area of Science:

• Auditory perception
• Visual perception
• Multisensory integration

Background:

• The ventriloquism effect (VE) demonstrates how visual stimuli can alter auditory localization.
• The ventriloquism aftereffect (VAE) shows adaptation in auditory perception following exposure to VE-inducing stimuli.
• Understanding auditory-visual integration is crucial for explaining spatial awareness.

Purpose of the Study:

• To investigate auditory-visual integration of distance perception.
• To examine visually-guided adaptation of auditory distance perception using VE and VAE.
• To determine the influence of visual displacement direction on VE and VAE.

Main Methods:

• Participants judged egocentric distance of auditory and auditory-visual stimuli in a reverberant environment.
• Visual stimuli were displaced closer (V-closer), farther (V-farther), or aligned (V-aligned) relative to auditory stimuli.
• VE and VAE were measured under different visual displacement conditions.

Main Results:

• Both VE and VAE were largely independent of target distance on a logarithmic scale.
• VE strength was approximately 72% of the auditory-visual disparity, irrespective of visual displacement direction.
• VAE was stronger for V-farther (44%) than V-closer (31%) conditions, with asymmetrical build-up/break-down rates.

Conclusions:

• Auditory-visual distance integration is independent of the direction of induced visual shift.
• Auditory recalibration (VAE) is stronger and faster when evoked by more distant visual stimuli.
• The findings shed light on the mechanisms of multisensory spatial re-calibration.