The Symbol of Time: Efficiency of shape stimuli drives time estimates

Visual stimuli are known to vary in their perceived duration, with a variety of features, including both high and low level, shaping temporal responses. For example, the size, memorability, or numerosity of stimuli lead to longer perceived intervals, thus highlighting the malleability of time perception. However, little is known about how stimulus shape may influence temporal perception. This feature is critical, as shape morphometry forms a general basis by which these other features may exert their influence on perceived duration. To investigate this, we conducted a series of three experiments looking at how specific characteristics of shapes are significant factors in the manipulation of time perception. We initially observed that greater shape angularity led to more precise time estimates, independent of shape identity. Next, we found that shapes and symbols with greater edginess, vertical asymmetry, and thickness led to longer perceived durations. Finally, we discovered that shapes built with higher numbers of geometrical primitives were perceived as longer, more precisely, and responded to more quickly, and were influenced by how subjectively meaningful they were to individual participants. Our findings suggest that certain aspects of shapes are able to manipulate time perception due to innate geometric qualities within the visual cortex itself.