Li Yang¹ (), Rachel Francis¹, Hyung-Bum Park², Weiwei Zhang¹; ¹University of California, Riverside, ²University of Chicago

The interaction between time perception and physical effort plays a crucial role in our daily activities, especially in contexts such as sports where precise timing is essential. The present study therefore aims to assess the effects of a simple(est) physical effort (i.e., isometric handgrip) on time perception with concurrent time reproduction and handgrip tasks. Specifically, the participants experienced a lapse of time at various levels while concurrently exerting grip force on a hand dynamometer at levels proportional to their maximum voluntary contraction (MVC). Immediately after, they pushed buttons to reproduce the perceived time interval. On the one hand, isometric handgrip can induce physical arousal, thereby accelerating time and leading to overestimated durations (i.e., arousal hypothesis). On the other hand, handgrip may directly impair time perception given the potential competition for magnitude-based processes underlying the two concurrent tasks, resulting in underestimated durations (i.e., Magnitude hypothesis). Our preliminary data revealed a significant increase in estimated duration under high physical effort compared to lower physical effort, supporting the arousal hypothesis. Some alternative accounts (e.g., response bias and effects on motor responses) were ruled out given that the handgrip effect was absent in a time production task where the required time duration was indicated by a numerical cue, instead of the actual passage of time. Together these findings suggest that physical effort can distort perceived time.