“…Tulane University CHANGED Many investigators (Reynolds, 1945;Sheffield, 1950;Stanley, 1952;Teichner, 1952;Wilson, Weiss, & Amsel, 1955) have reported faster extinction following a change in intertrial interval at the onset of extinction. This observation led to the hypothesis (Reynolds, 1945;Rothkopf, 1953Rothkopf, , 1955Teichner, 1952;Teichner & Holder, 1952) that the stimulus complex present at the beginning of a trial in a series of relatively massed trials includes temporally decaying traces of response-produced stimulation from the preceding trial or trials. The response, then, is conditioned to whatever magnitude of such traces remains at the end of the intertrial interval.…”