Visual recalibration of auditory spatial perception decays at different time scales

摘要

In human observers, exposure to audiovisual stimuli with a consistent spatial disparity results in an adjustment of auditory spatial representations that corrects for the mismatch between auditory and visual input (known as the ventriloquism aftereffect). Our recent findings suggest that such adjustments occur in parallel at multiple time scales. However, it is not clear if recalibration of auditory space, once emerged, remains stable until new audiovisual evidence is encountered, or would decay over time. Here we reanalyzed data from a previous study to answer this question. In this study, human participants localized sounds in complete darkness, immediately before and after they were exposed to 200 audiovisual stimuli in which the visual stimulus was consistently displaced to the right of the sound source. A trial-by-trial analysis of the localization responses in the auditory localization posttest suggested that the size of the ventriloquism aftereffect was strongest at the beginning and decreased over the course of the 96 unimodal localization trials. Thus, cross-modal recalibration decayed although participants did not experience any new audiovisual evidence. Despite this rapid decay, a stable carryover effect on sound localization was observed on the next day, suggesting distinct underlying mechanisms for immediate and sustained cross-modal recalibration effects.