Effect of Movement and Vision on Visual-Motor Adjustment to Optical Rearrangement

This study examined the effects of three conditions of movement (active, passive, and eye movement only) combined with two conditions of vision (sight and no sight of the body) on visual-motor adjustment to a familiar but optically rearranged environment. A total of 175 male college students were subjects. Each subject wore a pair of 25-diopter prism glasses while performing one of seven possible tasks. Visual-motor adjustment was measured by means of a mirror-box test administered prior to, and immediately following, performance of a 15-min. treatment session. Analysis of covariance indicated significant main effects for vision and a significant interaction between conditions of movement and vision. The actively moving subjects with sight of their bodies made significantly greater visual-motor adjustment to the optically rearranged environment than those in any of the other conditions investigated. The fact that non-moving subjects made small but significant adjustment was unexpected and remains unexplained.

Adaptation to Displaced Vision after Experience with Lesser Displacements

Adaptation to vision displaced by a 30 diopter prism was greatest after prior experience with a 30 diopter prism, less after experience with a 20 diopter prism, and least after experience with prisms of 10 and 20 diopters. This order was reversed when aftereffects were observed under normal vision, i.e., undistorted by prisms.