Time in the eyes: Covariant temporal compression and pupil constriction to impending collision

Abstract

Time perception can not only be influenced by the physical properties of external stimuli but also the observer's internal mental states. It remains unclear, though, whether the threatening information conveyed by visual collision can influence subjective time perception. Here we simulated an impending-collision scenario by rendering a looming ball in a virtual 3D space, and observers were asked to judge the duration of the looming ball which targeted at the center of their head (direct hit), at their fringe (marginal hit) or off their head (miss). Results showed that the looming ball in the two hit conditions was perceived as significantly shorter in duration relative to that in the miss condition. By directly comparing the effects with looming vs. receding balls, we further showed that the observed time compression effect could be attributed to the perceived threat information as well as the moving distance of visual stimuli. More intriguingly, the collision-induced threatening information reduced the pupil size at a short latency (500 ms) post stimulus onset, and the magnitude of the pupil constriction was positively correlated with the strength of the temporal compression effect. Together these findings provide compelling evidence that threatening information shortens perceived duration of visual stimuli and evokes pupil constriction responses, and highlight a covariant relationship between the psychological and physiological responses in the visual perception of ecologically salient information.

Meeting abstract presented at VSS 2016