THE EFFECTS OF RELATIVE ORIENTATION OF SURROUNDING GRATINGS ON BINOCULAR RIVALRY AND APPARENT BRIGHTNESS OF CENTRAL GRATINGS

Abstract

To find the effects of relative orientation of surrounding gratings on visibility (dominance) of central gratings in binocular rivalry and on apparent brightness of central gratings, we examined how the visibility (Exp. I, II) and the apparent brightness (Exp. III) would be changed as the function of the angle (θ), or orientation difference, between the central and the surrounding gratings. The results indicated that similar effects were found in the binocular rivalry experiments and in the apparent brightness experiment: Both the dominance time of the central grating in binocular rivalry and the apparent brightness of it were minimum at 20° in θ, and they increased as θ increased or decreased from 20°. These results were explained by the hypothesis of mutual inhibition between orientation detectors.