Renewal after overexpectation.

Four magazine approach experiments were performed with rats to explore the decrement produced by reinforcing a compound of two previously conditioned stimuli. Compound presentation produced the usual over-expectation decrement in responding to the individual stimuli. However, testing in an alternative, but similarly treated, context allowed renewal of the initial responding to the individual stimuli. This renewal is similar to that seen after a decrement produced by nonreinforcement. It joins other results in suggesting that the decrement produced in extinction and overexpectation may be due to the same mechanism.