Instrumental Escape Responding after Passive Avoidance Training: Support for an Incompatible Response Account of Learned Helplessness

Abstract

Two experiments using rats as subjects examined the relative degree of interference (helplessness) occasioned by pretreatment experiences with either passive-escape training or noncontingent, inescapable shock. In Experiment 1, passive-escape subjects initially learned to terminate shock by not running (forward or backward) and subsequently were tested in a shuttle box appartus that required an instrumental running response for termination of a moderate level (.5 mA) shock. A group of subjects yoked to passive escape subjects during the initial training stage experienced inescapable shock prior to shuttle-box testing. An additional group of subjects experienced no pretreatment but was required to learn that shuttling (running) terminated shock during the test phase. Experiment 2 included the same three experimental conditions except that a more intense shock (.8 mA) was used during shuttle-box testing. The results indicated that interference (helplessness) effects occurred uniformly for passive-escape and yoked subjects with a moderately aversive test stimulus (Experiment 1). With a highly aversive test stimulus, interference effects were observed following passive escape training, but were absent following pretreatment exposure to inescapable shock (Experiment 2). The theoretical implications of these data for interference theories (viz., the learned helplessness hypothesis and the incompatible motor response hypotheses) were discussed.