Abstract
Purpose: Stimulating one eye with a high-contrast dynamic stimulus can render a salient stimulus in the other eye invisible (continuous flash suppression; CFS). We have previously demonstrated, using a flickering achromatic Gabor as the suppressing stimulus, that successive exchanges of the eye-of-presentation led to breaking suppression (Shimizu & Kimura, VSS2016). This finding suggested that CFS is mainly mediated by eye- rather than stimulus-based suppression. This study aimed to extend the previous finding and investigated whether different suppressing stimuli such as Mondrian patterns would produce similar or different suppression. Method: The suppressing stimulus was a series of different Mondrian patterns presented at a rate of 5 Hz. The patterns were either achromatic or chromatic. The target was an achromatic Gabor patch (2.5 cpd, sigma = 0.22°, 40% contrast). The eye of presentation was manipulated in three conditions. In the dichoptic condition the suppressing stimulus was presented to the observer's dominant eye and the target was to the other. In the eye-swap condition the two stimuli were dichoptically presented but repeatedly exchanged between the eyes at every 1 second. In the monocular condition they were presented in the same eye. We asked observers to detect the target as soon as possible and measured detection time. Results & Discussion: In the dichoptic condition, Mondrian patterns, whether achromatic or chromatic, produced longer detection time (i.e., stronger suppression) than the Gabor patch used previously. Moreover, in contrast to the results with the Gabor, Mondrian patterns resulted in significantly longer detection time (3.7 sec) in the eye-swap condition than in the monocular condition (1.9 sec), although the suppression was much reduced relative to that in the dichoptic condition (8.7 sec). The significant, although reduced, suppression in the eye-swap condition cannot be easily accounted for by eye-based suppression, and implicates a partial contribution of eye-independent, possibly stimulus-based, suppression.
Meeting abstract presented at VSS 2017