After-Effects of Prolonged Inspection of Apparent Movement

Abstract

The study reported here is concerned with the validity of the general isomorphic assumption of Gestalt psychology which K6hler states as follows: experienced order in space is always structurally identical with functional order in the distribution of underlying brain processes.' The question immediately prompted by this statement is: Does experienced order in space, as defined by person's report of what he sees, correspond to a functional order in the underlying brain processes? To answer this question, an experiment was devised that permitted prediction based upon the isomorphic assumption. Apparent (stroboscopic) movement, in which the phenomenal experience of moving object occurs in the absence of physical movement in the stimulus-field, was used. In such situation, isomorphism makes unique prediction; its designation of the phenomenal field as the datum for cortical events can be translated into an experimental hypothesis. Thus it makes the prediction that the experience of apparent movement, which is based solely upon phenomenological data, is necessary and sufficient condition for the occurrence of corresponding cortical processes. If this deduction can be demonstrated, then the isomorphic assumption is supported. The present study measures the cortical correlates which underlie the inspection of series of highly similar stimulus-situations only one of which gives rise to the experience of apparent movement. The data provide test of the hypothesis that the cortical correlate of apparent movement differs from those associated with the control conditions.