Effect of photometric brightness on judgments of distance.

Abstract

Relative distance judgments were obtained for varying brightness ratios under binocular and monocular viewing conditions using the method of constant stimuli. Subjects had normal visual acuity but varied ocular dominance. The apparatus assured the control of lateral eye movements, color temperature, accommodation, and extraneous cues. Psycho-physical functions indicated that brightness is a factor in distance judgments for binocular and monocular conditions. Bright distant objects are equivalent to dim, near objects. The effect of brightness operated at lower levels of illumination. Ocular dominance may account for the observer bias found in the experiments.