Abstract

It is well known that estimated duration on moving stimulus which is presented about one second might be distorted depending on its spatial features. The distortion disappeared, however, when spatial features of a pair of measuring stimulus are perceived as the same with depth cue. This phenomenon is called time constancy. The aim of the current research is to examine the alternative hypothesis that time constancy is a consequence of size constancy. In the study, Mueller-Lyer illusion was used to measure perceived duration on a pair of stimulus which has the same retinal or perceived motion trajectories. The result shows that estimated duration of the test stimulus was overestimated when the length of perceived trajectories was longer than retinal trajectories compared to that of the standard stimulus and underestimated when the length of perceived trajectory was smaller than retinal trajectory compared to that of the standard stimulus. This implies that distortion in duration perception could be caused even when motion trajectory was perceived the same. This finding is a counterexample against the alternative hypothesis that time constancy might be a consequence of size constancy.