Answer
spontaneous recovery
Explanation
Spontaneous recovery is the re appearance of a response. It can occur after a period of non-exposure to the Conditioned Stimulus.If the conditioned stimulus and unconditioned stimulus are no longer associated, extinction will occur very rapidly after a spontaneous recovery.When An animal is conditioned to salivate to a metronome using Pavlovian procedures then the animal is removed from the test situation for several days and then returned to the test situation, the conditioned response is seen again this is reappearance of the conditioned response after a period and referred to as spontaneous recovery