Adaptation to uniocular image magnification: modification of the disparity-depth relationship.

Experimental subjects were exposed to a meridional size lens for one hour. Measures of adaptation and aftereffect showed significant adaptive shifts. Control subjects, who were exposed to nondistorting plain glass for one hour, did not show shifts. The results are interpreted as a revaluation of the relationship between binocular disparity and perceived depth as a result of exposure to informational discrepancy. Experiments by Wallach et al. and Epstein have shown that durative exposure to informational discrepancy, involving binocular disparity and the kinetic depth effect, leads to modification of the disparity-depth relationship.1 The present experiment investigated the modifiability of the disparity-depth relationship with a new procedure. A meridional size lens (MSL) before one eye magnifies the image in that eye along the meridian perpendicular to the axis of the lens. With the lens's axis at 900 (vertical), the image is magnified in the horizontal meridian. Uniocular horizontal magnification changes the disparities between the images of the two eyes, causing highly predictable perceptual distortions. Ames has provided verbal and graphic descriptions of the perceptual effects.2 One of these effects was measured in the present experiment. The frontal plane Received for publication December 29, 1969. This investigation was supported by research grant MH-16399-02 from the National Institute of Mental Health. 1 H. Wallach, M. E. Moore, and L. Davidson, Modification of stereoscopic depth perception, this JOURNAL, 76, 1963, 191-204; W. Epstein, Modification of the disparity-depth relationship as a result of exposure to conflicting cues, this JOURNAL, 81, 1968, 189-197. 2 A. Ames, Jr., Binocular vision as affected by relations between uniocular stimulus-patterns in commonplace environments, this JOURNAL, 59, 1946, 333-357.