The subjective duration of audiovisual looming and receding stimuli

Looming visual stimuli (log-increasing in proximal size over time) and auditory stimuli (of increasing sound intensity over time) have been shown to be perceived as longer than receding visual and auditory stimuli (i.e., looming stimuli reversed in time). Here, we investigated whether such asymmetry in subjective duration also occurs for audiovisual looming and receding stimuli, as well as for stationary stimuli (i.e., stimuli that do not change in size and/or intensity over time). Our results showed a great temporal asymmetry in audition but a null asymmetry in vision. In contrast, the asymmetry in audiovision was moderate, suggesting that multisensory percepts arise from the integration of unimodal percepts in a maximum-likelihood fashion.