Abstract
Purpose: A salient stimulus in one eye can be rendered invisible by presenting a high contrast flickering grating to the other eye (continuous flash suppression, CFS). This study investigated the effects of eye of presentation (which eye received which stimulus) on strength of CFS. Method: The suppressing stimulus (suppressor) was a counterphase-flickering (5 Hz) vertically-oriented Gabor patch (2.5 cpd, sigma = 0.22 degrees, and 100% contrast). The target was a horizontally-oriented Gabor patch of the same spatial properties (40% contrast). Eye of presentation was manipulated in three conditions. In the dichoptic condition, the suppressor and the target were presented at the same retinal position of different eyes, whereas in the monocular condition they were presented to the same eye. In the eye-swap condition, they were presented to different eyes but eye of presentation was repeatedly swapped at 1 Hz. On each trial, the suppressor was initially presented alone to establish perceptual dominance and 0.5 - 2 sec later the target was introduced. The contrast of the target was gradually increased to 40% over a 1-second period and then remained constant. We asked observers to detect the target as soon as possible and measured detection time. Results & Discussion: In the dichoptic condition, the detection time was long (Mean = 4.74 sec), indicating robust CFS. In the eye-swap condition, however, the target was detected much faster (Mean = 2.52 sec) and the detection time was not significantly different from that in the monocular condition (Mean = 1.51 sec). These results showed that disrupting the eye-of-origin information almost eliminated the potency of CFS. The present findings suggested that CFS is mainly mediated by eye rivalry (rivalry between the eyes) rather than stimulus rivalry (rivalry between stimuli).
Meeting abstract presented at VSS 2016