Anisotropy in Werner's binocular depth contrast effect

Abstract

We investigated Werner's binocular depth contrast effect. Subjects viewed stereograms consisting of a test pattern and an inducing pattern. The halfimages of the inducing pattern were either horisontally scaled or sheared relative to each other. Subjects judged the (induced) percieved slant of the test pattern. We were interested in what in uence the spatial configuratio of the test patern and the inducing pattern had on the depth contrast effect. We conclude that the depth contrast effect is a global effect. In other words it is not restricted to the location of the inducing pattern. The effect decreases with distance, however, in an anisotropic way. The depth contrast effect was presented most prominently when the test pattern was positioned in the direction along the slant (rotation) axis of the inducing pattern. We suggest that werner's depth contrast effect can be explained by the (previously reported) finding that 1) stereopsis is very sensitive to horisontal scale and shear of two stimuli relative to each other.