Abstract
Peripheral vision (20–40° eccentricity) has been characterized extensively, but there is limited research extending to the 95+° limits of the human visual field. Flickering stimuli appear to flicker more rapidly when viewed in the extreme periphery than when they are foveated (Shimojo, VSS‘19). Here, we find that this effect generalizes to another form of dynamic perception: Rotating stimuli in the extreme periphery are perceived as rotating faster than identical stimuli presented at the fovea (bars, crosses, cartoon icons, 2–4° visual angle). When the peripheral stimulus was enlarged (2–3×), speed mismatch was increased, suggesting that the effect is not based simply on cortical projection sizes. Comparisons of speed mismatches with bar-shaped and cross-shaped stimuli suggested that the effect may be driven by raw motion energy. When a long row of rotating stimuli is presented, the last stimulus in the periphery is perceived as rotating faster, while the rest appear more or less uniform. Removing the last stimulus causes the next in line to appear uniquely fast. In addition, when stimuli are shown in a large array, stimuli on the corners of the array appear to rotate faster than the rest (demonstrated at VSS 2018 Demo Night). This suggests involvement of a surround-suppression mechanism, as found in basic motion processing. The perception of rotation rate is likely to involve a combination of object-based tracking of rotation angles, and the processing of raw motion energy. Differences in visual acuity may cause foveal vision to rely more on object tracking and peripheral vision to rely more on motion energy. Perceptual mismatches may arise when attempting to comparing across such different process outputs.
Acknowledgement: Yamaha Motor Corporation U.S.A., JST-CREST