Spontaneous recovery

Spontaneous recovery is a phenomenon of learning and memory that was first named and described by Ivan Pavlov in his studies of classical (Pavlovian) conditioning. In that context, it refers to the re-emergence of a previously extinguished conditioned response after a delay. Such a recovery of "lost" behaviors can be observed within a variety of domains, and the recovery of lost human memories is often of particular interest. For a mathematical model for spontaneous recovery see Further Reading. Classical conditioning Spontaneous recovery is associated with the learning process called classical conditioning, in which an organism learns to associate a neutral stimulus with a stimulus which produces an unconditioned response, such that the previously neutral stimulus comes to produce its own response, which is usually similar to that produced by the unconditioned stimulus. Although aspects of classical conditioning had been noted by previous scholars, the first experimental analysis of the process was done by Ivan Pavlov, a nineteenth-century physiologist who came across the associative effects of conditioning while conducting research on canine digestion. To study digestion, Pavlov presented various types of food to dogs and measured their salivary response. Pavlov noticed that with repeated testing, the dogs began to salivate before the food was presented, for example when they heard the footsteps of an approaching experimenter. Pavlov named this anticipatory behavior the "conditioned" response or, more exactly, the "conditional" response. He and his associates discovered and published the basic facts about this process, which has come to be called classical or Pavlovian conditioning. Among the phenomena that Pavlov observed was the partial recovery of a classically conditioned response after it had been extinguished by withholding the unconditioned stimulus. This recovery happened in the absence of any further unconditioned stimulation. Pavlov referred to this phenomenon as spontaneous recovery.