Abstract
Time flows in one direction. However, when we asked participants to judge whether short video clips were played in forward or reverse direction, they were not able to discriminate them all. Some were easy to judge (e.g., animals moving forward, objects falling) but others were not (e.g., conversations, musical performances). Does salient information on time direction affect time-length perception? In this study, participants were required to judge whether a 3-second video stimulus was longer or shorter than 3 s. Stimuli were divided into two groups according to the saliency of time direction and were played in forward or reverse. We found that the salient video clips were perceived as significantly longer than the ambiguous ones (p=0.00023), whereas the direction of playback had no effect. Motion energy affected perception of the ambiguous group in particular. Salient information on the direction of time flow increases time-length perception irrespective of the motion energy.
