Abstract

The Journal of General Psychology, 1949, 4l., 27-32. Department of Psychology, UniverJity of Wyoming WILSON J. WALTHALL, JR. In Dynamics in Psychology, 1940, Kohler presented a “current” theory of perception (1). The principal experimental bases of the theory were changes in the rate of reversal of ambiguous figures and the effects of certain percepts on immediately following percepts. In 1944, Kohler and Wallach greatly implemented both the theory and the experimental basis thereof (3). They demonstrated the relationship between Kohler’s earlier work and the studies of the figural after-effects made by Gibson, Bales and Follansbee, and others. Their generalized experimental finding with respect to the relationship among all these studies of figural after-effects was that one of the effects of a percept on a succeeding percept was to displace the succeeding percept away from the site of the original percept except at places of coinci- dence between the two. The displacing force attained a maximum value a short distance out from the site of the original percept. With the appropri- ate arrangement of the figures, this displacing effect resulted in a decrease or an increase in the apparent size of the succeeding figure. Kohler and Wallach included in their