Sniffy the rat has been taught to press a bar in a cage to receive food. The behavior disappeared, though, when Sniffy stopped getting food following bar-pressing. Several days later, Sniffy was put in the cage again, and he immediately began to press the bar. The reappearance of this response is called .

spontaneous recovery

Explanation:Spontaneous recovery is a term associated with learning and conditioning. Specifically, spontaneous recovery is the reappearance of a response (a Conditioned Response; CR) that had been extinguished. The recovery can occur after a period of non-exposure to the Conditioned Stimulus (CS).

Spontaneous recovery is the reappearance of a Conditioned Response (CR) that has been extinguished. Pavlov and his classical conditioning experiments found that spontaneous recovery can occur after a period of not being exposed to the Conditioned Stimulus (CS).