Abstract
Nearer objects and surfaces occlude further ones differently in the two eyes, resulting in regions on the distant surface visible to one eye but not the other, called monocular occlusion zones. Shimojo and Nakayama (1990) showed that geometrically valid monocular occlusion zones resist rivalry. We used phantom stereograms (Gillam& Nakayama, 1999), to investigate how binocular rivalry might manifest in monocular occlusion zones in the absence of an explicit surface. Participants reported the frequency and duration of monocular feature suppression and perceived depth for three variations of a phantom stereogram. Of these variations only one fully satisfied the geometric relationships consistent with a nearer occluding surface. When a stimulus is geometrically consistent with occlusion, a greater frequency and duration of depth, and a lower frequency and duration of suppression, should be reported, compared to an arrangement inconsistent with occlusion. Results showed significant differences in frequency and duration of perceived depth as a function of geometric consistency. However, geometric consistency did not influence overall rivalry. Further analysis revealed differences in how rivalry manifested as a function of stimulus validity. We conclude that while geometric validity did not eliminate binocular rivalry in these stimuli, it did alter the features that were suppressed.
Meeting abstract presented at VSS 2012