Perceived duration of plaid motion increases with pattern speed rather than component speed

Several studies have shown that visual motion distorts perceived duration: The duration of fast-moving stimuli is judged to be longer than the same duration of stationary or slow-moving stimuli. However, it is still unclear which stages of motion processing are involved in this apparent dilation of the perceived duration. In this study, using a two-dimensional pattern motion of a plaid as a stimulus, we systematically manipulated the speed of pattern and component motions of the plaid to examine which motion information influences the perceived duration of the plaid stimuli. Experiment 1 found that perceived duration increased with pattern speed, even though component speed was constant. Experiments 2 and 3 revealed that perceived duration was unchanged, even though component speed increased, as long as the pattern speed was identical. Experiment 4 used both static and moving plaids and confirmed that the results of Experiments 1-3 reflected duration dilation, not duration compression, induced by motion. These results suggest that higher order visual processing in the middle temporal area may play an important role in motion-induced duration dilation.