title: The effect of perceptual grouping on perisaccadic spatial distortions.
abstract: Perisaccadic spatial distortion (PSD) occurs when a target is flashed immediately before the onset of a saccade and it appears displaced in the direction of the saccade. In previous studies, the magnitude of PSD of a single target was affected by multiple experimental parameters, such as the target's luminance and its position relative to the central fixation target. Here we describe a contextual effect in which the magnitude of the PSD for a target was influenced by the synchronous presentation of another target: PSD for simultaneously presented targets was more uniform than when each was presented individually. Perisaccadic compression was ruled out as a causal factor, and the results suggest that both low- and high-level perceptual grouping mechanisms may account for the change in PSD magnitude. We speculate that perceptual grouping could play a key role in preserving shape constancy during saccadic eye movements.
authors.affiliation: Vision Science Group, School of Optometry, University of California, Berkeley, CA, USA. jtong@braintrauma.org
authors.forename: Jianliang
authors.initials: J
authors.lastname: Tong
authors.forename: Zhi-Lei
authors.initials: ZL
authors.lastname: Zhang
authors.forename: Christopher R L
authors.initials: CR
authors.lastname: Cantor
authors.forename: Clifton M
authors.initials: CM
authors.lastname: Schor
mesh_terms: D005403:Fixation, Ocular; D006801:Humans; D010775:Photic Stimulation / Q000379:methods; D011597:Psychomotor Performance / Q000502:physiology*; D012438:Saccades / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*