Abstract
One hypothesis accounting for the fact that we are not aware of the retinal smear caused by saccades in normal viewing situations is that this smear is masked by pre and/or post-saccadic static images (Matin, Clymer & Matin, Science 1972; Campbell & Wurtz, Vis. Res. 1978). We establish an objective measure of saccadic masking by presenting a point light source during the saccade, which--if not masked--was perceived as a smear. A brief luminance decrease of the point light source at various times during the saccade resulted in the percept of a hole in various locations in the smear. Without pre- or post-saccadic masks, subjects could reliably report the location of the hole. We varied the presence and duration of forward (pre-saccadic) and backward (post-saccadic) masks by additionally illuminating the point light source before and after the saccade. We found a decrease in hole localization performance with increasing mask durations, as measured by the slope of single-stimuli psychometric functions. Interestingly, we also found significant individual differences in susceptibility to masks in general, and in differential susceptibility to forward versus backward masks. To examine the origin of saccadic masking, we correlated performance in the saccadic smear masking task with performance in classic visual masking tasks during fixation. We hypothesize that if masking of saccadic smear is a purely visual process, individual differences in susceptibility to masking should generalize across the two different masking paradigms.
Meeting abstract presented at VSS 2014