Modification of the disparity-depth relationship as a result of exposure to conflicting cues.

Prominent among investigations of intramodal discrepancy is the series of experiments reported by Wallach et al.2 Wallach's Os viewed a rotating tridimensional, skeletal wire-form which was presented for observation in a mirror telestereoscope." Rotation of the form provided the continuous optical transformations that produce the kinetic depth effect (KDE) and accurate depth-perception." At the same time, the telestereoscopic arrangement doubled the disparity, leading to significant overestimation of depth. In the standard experiment, O provided initial estimates of the depth and height of a stationary form viewed telestereoscopically. Then O observed the form rotating in the telestereoscope for 1-10 min. intervals. After training, O repeated the depthand height-judgments while the form was stationary. The main finding was a significant decrease of the depth-estimate, as a linear function of log training time. The height-judgments did not change. Wallach et al. considered the altered depth-estimates to be the result of perceptual learning. The existence, during training, of a consistent discrepancy between the depth specified by disparity and KDE resulted in a modification of the disparitydepth relationship. A given degree of disparity, which elicited a specific magnitude of perceived depth before training, elicited a different (reduced) magnitude of perceived depth after training. O was presumed to have learned a new relationship between disparity and depth.