Abstract
The mechanism underlying binocular single vision is generally thought to involve a unification of information from each eye into a common stream that eventually leads to perception. However, the phenomenon of binocular rivalry shows that binocular vision does not always involve integration of the two eye views. One explanation for how the visual system deals with monocular signals in such different ways is that rivalry only occurs when binocular correspondence cannot be solved. A prediction of this model is that stereopsis should not be possible during binocular rivalry. In this study, subjects viewed a stimulus comprised of three vertically arranged grating patches. The top and bottom patches were given equal and opposite horizontal disparities such that one or other was in front of fixation during the stereo presentation. The grating patches in the two eyes differed in their spatial frequency, spatial phase, orientation or direction-of-motion. The task of the subjects was to press a button to indicate which grating patch (top or bottom) was closest. Immediately after their stereo judgment, subjects were asked to indicate the perceptual appearance of the gratings. The results show that stereopsis is possible even when the form from one eye is suppressed from awareness during binocular rivalry. These findings are consistent with the idea that the integration of information from the two eyes can occur independently for different aspects of vision.