Hiu Mei Chow¹ (), Jialiang Ma², Satoshi Shioiri², Chia-Huei Tseng²; ¹St. Thomas University, Fredericton, Canada, ²Research Institute of Electrical Communication, Tohoku University, Sendai, Japan

Human observers make saccades (large shifts of eye gaze) frequently as we explore the world visually, which creates motion blur or smears on the retina. However, we perceive a stable visual world and do not notice motion blur. That is because our brains selectively block visual processing during eye movements (i.e. saccadic suppression). One example of saccadic suppression is our inability to detect a target location change during saccades (i.e. saccadic suppression of target displacement), which might be explained by the assumption that the world is stable. As our world is multi-sensory and non-visual signals like sound are important elements for a stable world, we tested whether sound affected the visual perception of target displacement during eye movement in an experiment. Sixteen observers reported whether a visual target jumped to the left or right (0.33°) when they made a saccade (18°). Critically, a pure tone was presented synchronously with the visual target, with a 100-ms gap at the time of saccade (audio-blank), potentially signalling a change in the visual event. Other times, the sound was constant (audio-no-blank, signalling no change) or absent (silent). Perceptual performance analysis showed that observers’ ability to discriminate target shift direction was significantly higher in the audio-blank condition than in the silent (p = .002) and audio-no-blank (p = .037). Despite a shorter saccade latency in the audio-blank than in audio-no-blank conditions (p < .001), saccade latency did not predict perceptual task accuracy (p = .10) on a trial-by-trial basis after sound manipulations were accounted for. These results highlight an auditory counterpart of the visual blanking effect of saccadic suppression, where a brief gap in the visual target at the time of saccades leads to better visual discrimination. Our work supports the role of sound in modulating visual stability perception during saccades.

Acknowledgements: Part of this work was carried out under the Cooperative Research Project Program of the Research Institute of Electrical Communication, Tohoku University (R05/A17) and Discovery Grant Program of Natural Sciences and Engineering Research Council of Canada (RGPIN-2024-06028).