Effects of Auditory Patterns on Judged Displacements of an Occluded Moving Object

Abstract

Abstract Using displays in which a moving disk disappeared behind an occluder, we examined whether an accompanying auditory rhythm influenced the perceived displacement of the disk during occlusion. We manipulated a baseline rhythm, comprising a relatively fast alternation of equal sound and pause durations. We had two different manipulations to create auditory sequences with a slower rhythm: either the pause durations or the sound durations were increased. In the trial, a disk moved at a constant speed, and at a certain point moved behind an occluder during which an auditory rhythm was played. Participants were instructed to track the occluded disk, and judge the expected position of the disk at the moment that the auditory rhythm ended by touching the judged position on a touch screen. We investigated the influence of the auditory rhythm, i.e., ratio of sound to pause duration, and the influence of auditory density, i.e., the number of sound onsets per time unit, on the judged distance. The results showed that the temporal characteristics affected the spatial judgments. Overall, we found that in the current paradigm relatively slow rhythms led to shorter judged distance as compared to relatively fast rhythms for both pause and sound variations. There was no main effect of auditory density on the judged distance of an expected visual event. That is, whereas the speed of the auditory rhythm appears crucial, the number of sound onsets per time unit as such, i.e., the auditory density, appears a much weaker factor.