Three experiments with rats examined reacquisition of an operant response after either extinction or a response-elimination procedure that included occasional reinforced responses during extinction. In each experiment, reacquisition was slower when response elimination had included occasional reinforced responses, although the effect was…

Discusses experiments involving classical conditioning of planarians. Suitable for advanced high school students or college-level independent study, flatworms are trained to curl up under a bright light. Then the planarians to are subjected to controlled reproduction experiments to determine whether the learned behavior is inherited by their…