Abstract
Visual masking is a well known phenomenon in which the visibility of a stimulus, the target, is reduced by the rapid presentation of either a subsequent or preceding stimulus, called the mask. In a typical masking paradigm participants are not allowed to move their eyes and asked to maintain fixation throughout the trial. Outside the laboratory, however, people typically make several saccadic eye movements per second. Since saccades have been shown to influence the perceived spatial and temporal properties of briefly presented stimuli, we investigated whether these changes in perception might also influence masking. We tested subjects, with and without saccades, in a series of masking experiments including metacontrast masking (a single target followed by a backward mask) and masking of a pattern by noise (repeated forward and backward masking in a sequence). We measured discrimination performance for the target as a function of when the target was shown with respect to saccade onset. We found that performance did indeed change during the time period around saccades, leading either to “unmasking” or stronger masking of the target, depending on the type of masking and the timing of the target and mask with respect to saccade onset. Overall, the results suggest that changes in perception around the time of saccades influence the spatial and temporal attributes of the target and mask. These results also imply that saccades might be useful, in everyday life, at reducing the influence of masking on perception of briefly presented targets.