Abstract
Because time cannot be directly perceived from sensory information, time perception of visual events depends on changes in visual attributes of the scene. Among these attributes, motion—change in space-time—is a fundamental cue for time duration estimation, and dynamic visual stimuli are, in fact, known to induce a time dilation effect—an illusion of lengthened time. Given recent findings that static images with implied motion can produce a time dilation effect and that looming visual stimuli are perceived as longer than receding ones, in this study we investigated the effect of directional congruency between two motion signals—looming/receding motion and implied motion in depth from an image—in subjective time dilation. In two experiments, observers were shown images of either front- or back-facing person in a running posture for one of seven probe durations (400–1000ms) and judged whether each presentation duration was more similar to the short (400ms) or to the long (1000ms) standard duration. The size of the running person image was either constant (Experiment 1), decreasing (receding, Experiment 2), or increasing (looming, Experiment 2) over the presentation time. In Experiment 1, we did not find any difference in perceived presentation duration between two running directions (front- vs. back-facing) depicted in images. In Experiment 2, however, we found a congruency effect between the directions of implied motion (front- vs. back-facing) and real motion in depth (looming vs. receding): the duration of the front-facing person image was perceived as longer when it was looming than receding, and the duration of the back-facing person image was perceived as longer when it was receding. These results suggest that higher-order motion processing which integrates signals of various types of motion is responsible for the perception of time duration.