Ourvisual world is usually filled with a myriad of different shapes, colors and forms. Some objects are large, others small; some red, others green or blue; some are regularly, some irregularly shaped. Psychologists have wondered what would happen if the visual field were uniform instead of varied, so that all the stimuli we received would be the same. They have therefore set up a homogeneous field or “Ganzfeld” (literally, “whole field”) by placing half a translucent ping-pong ball over each eye of their subject, or by having him look into large white spheres (Dember, 1960).In either case any light that reaches the eyes comes from a uniform visual fieldThe most interesting finding in these experiments is that colors tend to disappear. When a red light is shown on the inside of the spheres it is first seen as a diffuse red fog, but after about three minutes most subjects report that the color vanishes and the spheres appear whitish. The same effect is obtained with green illumination. Later on “inhomogeneity” is gradually introduced into the Ganzfeld in various ways. Figures then start to emerge and certain fundamental properties of the background, such as color and distance, become stabilized.These experiments indicate that both the registration of color and the visual perception of forms are due to stimulus change, or heterogeneity, in our field of vision. The absence of contrast actually denudes our world and distorts our experience. A similar effect has been noted in sensory deprivation experiments in which all external stimulation—visual, tactual, auditory, etc.—has been reduced to a minimum. See SENSORY DEPRIVATION.