Gamma Movement: Apparent Movement in Figural Aftereffects Experiments

Abstract

Standard contour circles, 40 mm. in diameter, were tachistoscopically presented for 1 sec. With each presentation, .8 sec. after the onset, one of a number of comparison circles, varying in diameter from 32 to 48 mm., was presented alongside for .2 sec. Those comparison circles which were equal to and slightly smaller than the standard circles were judged larger significantly more often than chance. Thus, the initial phase of gamma movement, the apparent expansion of briefly exposed figures, was elicited under conditions comparable to those of some figural aftereffect experiments.