Does time-shrinking take place in visual temporal patterns?

The duration of a short empty time interval (typically shorter than 300 ms) is often underestimated when it is immediately preceded by a shorter time interval. This illusory underestimation - time-shrinking - had been studied only with auditory temporal patterns. In the present study, we examined whether similar underestimation would take place with visual temporal patterns. It turned out that underestimation of the same kind takes place also in the visual modality. However, a considerable difference between the auditory and the visual modalities appeared. In the auditory modality, it had been shown that the amount of underestimation decreased for preceding time intervals longer than 200 ms. In the present study, the underestimation increased when the preceding time interval varied from 160 to 400 ms. Furthermore, the differences between the two neighbouring intervals which could cause this underestimation had always been in a fixed range in the auditory modality. In the visual modality, the range was broader when the intervals were longer. These results were interpreted in terms of an assimilation process in light of the processing-time hypothesis proposed by Nakajima (1987 Perception 16 485-520) in order to explain an aspect of empty-duration perception.