2011 年 30 巻 1 号 p. 19-24
Auditory stimuli are known to alter visual perception. However, the effects of such stimuli on velocity perception have not yet been examined. A well-known velocity illusion related to object size is described by Brown's law. We can easily match object size with sound intensity. Therefore, this study examined the potential modification of velocity perception by auditory stimuli at different sound pressure levels (SPLs). The results showed that the perceived velocity, particularly when the object size was small, diminished with a high SPL auditory stimulus. We assume two interpretations of this result. First, high intensity sounds can modify the perceived object size and alter the perceived velocity by replicating Brown's law since large objects tend to match well with high SPL sounds. Second, previous studies indicated that stimuli with strong intensities seem to have been presented for longer durations. Thus, stimulus duration may be perceived as longer when higher SPL sounds are presented simultaneously, which may cause the velocity to be perceived as being slower.