Temporal acuity of vision decreases with eccentricity and is associated with schizotypy

Temporal acuity reflects our ability to consciously detect a perceptual change within a short period of time, such as an asynchrony separating two visual events. Asynchrony discrimination skills shape the temporal structure of perception, by determining whether distinct information is bound or segregated in time. Given the crucial role of peripheral vision in everyday tasks, such as dynamically adapting our locomotion, we evaluated asynchrony discrimination in periphery under conditions of natural vision. Further, previous research showed perceptual disturbances in patients with schizophrenia, with defective visual asynchrony processing. Exploring whether such a deficit extends to neurotypical individuals with schizotypal traits and varies across the visual fields is essential given the significance of abnormal perceptual experiences in the schizophrenia spectrum. In this virtual reality study, fifty participants performed a simultaneity judgment task within immersive virtual reality to estimate visual temporal acuity across space and filled the schizotypal personality questionnaire. Participants assessed the presence or absence of a 22 ms asynchrony between the onset of two targets. Targets were located at different eccentricities spanning the whole binocular fields and across horizontal and vertical meridians. Topographic maps were computed to visualize asynchrony discrimination skills across the visual space in two different (natural and artificial) virtual environments. Our results are threefold. First, the temporal acuity estimated in a traditional psychophysical visual context does not generalize to an ecologically-valid landscape scenery, such that asynchrony discrimination is reduced under natural vision conditions. Second, the temporal acuity of vision decreases as the eccentricity of the targets increases, but it remains constant across meridians. Third, this deterioration of temporal coding in peripheral vision concerns non-medicated individuals self-reporting perceptual and cognitive schizotypal traits. The results suggest that distinct temporal mechanisms in central and peripheral vision drive visual temporal acuity. Furthermore, perceptual and cognitive disturbances in the neurotypical population may be linked to abnormal temporal processing in peripheral vision. Overall, these findings may pave the way toward novel investigations into the variety of time experiences across neurotypical and neurodivergent populations.