THE ROLE OF INTERMITTENT SHOCK-POSTPONEMENT IN REINFORCEMENT BY TIMEOUT FROM AVOIDANCE

Abstract

A signaled timeeut fnom an avoidance contingency has been shewn te neinf orce behavier when pregnammed en vanious intenmittent schedules, but most contemporary studies confeund the timeeut with sheck-pestpenement: After each timeeut, the aveidance centingency is restanted at the beginning of the nesponse-sheck interval, as if an aveidance response had eccunred. Tha present expeniment assessed the centnibution of this intenmittant aveidance function te the maintenance of the response leading te timeeut. In baseline cenditiens, rats’ presses en ene leven postponed sheck fer 30 s while presses en anothen leven pneduced, accerding to a variable-interval schedule, a 90-s timeeut duning which the shock-pestponement schedule was suspended and its correlated stimuli were removed. At the end of the timeout, the shock-postpenement schedule was reset te the beginning of the 30-s response-sheck intenval. In the experimental cenditien, the timeeut duration was neduced te Os, se that satisfying the VI schedule merely resetthe respense-shock interval. Responding en the aveidance leven was maintained threugheut the expeniment. Respending en the timeout ayer was maintained unden baseline cenditiens, but net when the timeeut was reduced Loo s. These nesults establish that respending en the timeout levar was maintained by the timeeut, not by the sheck-pestpenement that fellewed it, and that the cenfound pnesant in se many studies of timeout from aveidance may be safely disneganded.