Movement Improves the Quality of Temporal Perception and Decision Making

Abstract

A critical aspect of behavior is that mobile organisms must be able to precisely determine where and when to move. A better understanding of the mechanisms underlying precise movement timing and action planning is therefore crucial to understanding how we interact with the world around us. Recent evidence suggest that our experience of time is directly and intrinsically computed within the motor system, consistent with the theory of embodied cognition. In order to investigate the role of the motor system, we tested human subjects (n=40) on a novel task combining reaching and time estimation. In this task, subjects were required to move a robotic manipulandum to one of two physical locations to categorize a concurrently timed suprasecond. Critically, subjects were divided into two groups: one in which movement during the interval was unrestricted and one in which they were restricted from moving until the stimulus interval had elapsed. Our results revealed a higher degree of precision for subjects in the free-moving group. A further experiment (n=14) verified that these findings were not due to proximity to the target, counting strategies, bias, or movement length. A final experiment (n=10) replicated these findings using a within-subjects design, performing a time reproduction task, in which movement during encoding of the interval led to more precise performance. Our findings suggest that time estimation may be instantiated within the motor system as an ongoing readout of timing judgment and confidence.

Significance Statement Perception is inherently a noisy process, wherein the nervous system must find a tradeoff between measurement noise, bias, distractions, and expectations. Recent evidence has begun to demonstrate that our perceptions and sensations are influenced by motor movements and actions. One area where this is of particular importance is the perception of time. Recent work has shown that our temporal perception fluidly changes with the length of our movements. Further, there is also evidence suggesting that movement not only biases perceived time, but can enhance it, suggesting the motor system directly influences temporal perception. We here show that when subjects are free to move during the timing of an auditory interval, the representation of that interval is enhanced.