Zhenni Wang^1,2, Lihui Wang¹; ¹Shanghai Jiao Tong University, ²Shanghai Mental Health Center

Magnitude biases temporal perception, with a high amount of visual stimuli perceived as lasting longer than a low amount of visual stimuli, even though they are presented for the same length of time. Despite the well-documented phenomenon, it is yet unknown if eye movements play a significant role in the magnitude-biased interval perception. In a two-alternative forced-choice task, participants were asked to compare two intervals and judge which was longer or shorter. In Experiment 1, a sequence of dots was consecutively presented in each interval. The dot was presented at a random location on the visual field and participants were asked to follow the dot with eye movements. Importantly, the number of dots in each interval was manipulated in the way that one interval included more dots than the other, even though the two intervals had the same length. The results showed that the interval with more dots were accompanied by more saccades, and were judged as lasting longer. Experiment 2 had the same design as Experiment 1 except that the dots were simultaneously rather than sequentially presented. As a result, relative to the interval with fewer dots, the interval with more dots did not induce more saccades than that in Experiment 1. Although the interval with more dots was still judged as lasting longer than the interval with fewer dots, the magnitude-biased interval perception was significantly weaker than that in Experiment 1. Together, the results suggested a critical role of oculomotor engagement in modulating the magnitude-biased interval perception.