Abstract
The perceived duration of events is affected by non-temporal attributes of stimuli, such as the number of components, size, or complexity. Presenting an observer with more stimuli tends to result in an overestimated duration. Although previous studies have suggested that time perception is influenced by the physical attributes of stimuli, it is not known whether time perception is influenced by differences in the subjective appearance of physically identical stimuli. Specifically, we examined whether the subjective area size of the critical object in an Ebbinghaus illusion influences its time perception. We measured the perception of time spent looking at visual objects whose perceived area size was altered by the Ebbinghaus illusion, in which a central circle surrounded by large inducers appears to be smaller than a central circle of the same size surrounded by small inducers. In the experimental trial, one of two types of surrounding circle (the subjectively large or small conditions) was randomly displayed for 1500 ms. The central circle appeared for either 150 or 350 ms. The participants estimated the duration of the central circle. The results showed that the perceived duration of the subjectively large condition was longer than that of the subjectively small condition, although the actual area size remained invariant. This suggests that later visual processing systems influence time perception, because the Ebbinghaus illusion is a prototype for size contrast illusions that affect cognitive judgment by introducing bias into the processing of information at a higher level of visual processing (Coren & Enns, 1993). In summary, these results are the first to show the effect of a size contrast illusion (the Ebbinghaus illusion) on processing the temporal characteristics of a stimulus. This indicates that the time perception of visual events is influenced by higher-level representation of visual processing.