Contrast dependency of sacadic compression and suppression

In the occurrence of a saccadic eye movement vision becomes suppressed. Supra-threshold visual stimuli that are briefly presented at that time become perceptually compressed towards the saccade target (saccadic compression) and shifted in saccade direction (saccadic shift). We show that the strength of saccadic compression, like the strength of saccadic suppression, varies with stimulus contrast. Low contrast stimuli lead to stronger compression than high contrast stimuli. The similarity of contrast dependence and time course suggests that saccadic compression is related to saccadic suppression. Because the saccadic shift did not depend on contrast we suggest that shift and compression are different effects.