The spatial pattern of peri-saccadic compression for small saccades.

In the temporal vicinity of a saccade onset, visual stability is transiently disrupted and briefly flashed visual stimuli undergo a systematic perceptual mislocalization. Specifically, when a stimulus is flashed around saccade onset, localization judgments are grossly biased toward the saccade endpoint. This peri-saccadic compression increases with saccade amplitude. Previous studies of peri-saccadic compression have typically used rather large saccade amplitudes. In the present study, we investigate systematically the pattern of errors for small saccade sizes (2°-10°), taking into account both the amplitude of the saccade and the position of the flashed stimulus (11 positions tested from 1 to 12°). Our results show a weaker compression effect for the smallest saccades. Moreover, we found that the strength of the compression depends on both stimulus side and relative distance to the saccade target.