Lateral Inhibition and Geometric Illusions

Abstract

It has been suggested that lateral inhibitory processes, operating through the mutual inhibition and displacement of spatially adjacent contours imaged on the retina, may account for many of the classical geometric illusions. Two experiments were conducted, one using an alternative form of the Poggendorff illusion, and the other an alternative form of the Muller—Lyer, in which the adjacent contours necessary for the operation of the inhibitory mechanism were eliminated. In both instances the illusion was still found to exist, although somewhat reduced in magnitude. These results indicate that lateral inhibition may play a contributory role in illusion formation, but it is not the primary casual, mechanism.