Uncontrollable shock proactively increases sensitivity to response-reinforcer independence in rats.

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Abstract
Learned helplessness theory predicts that animals exposed to inescapable shock acquire an expectancy of response-reinforcer independence, which proactively interferes with learning of response-reinforcer dependence. The theory also predicts that this expectancy can increase sensitivity to subequent instances of response-reinforcer independence. The latter prediction was tested in a paradigm that minimizes the confounding effects of shock-induced activity deficits. Rats were trained to respond for food, then given either escapable, inescapable or no shock. They received 2 sessions of response-contingent food followed by sessions of noncontingent food deliveries. During this phase, inescapably shocked animals decreased responding faster than did controls. Experiment 2 replicated this finding with a different schedule of food delivery and a procedure that more directly minimized the possibility that the outcome is due to either direct or indirect shock-induced activity changes. The prediction that uncontrollable aversive events can increase an animal''s sensitivity to noncontingent response-reinforcer relationships was supported.