Spontaneous recovery

Spontaneous recovery is a phenomenon of learning and memory which was first seen in classical (Pavlovian) conditioning and refers to the re-emergence of a previously extinguished conditioned response after a delay.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, conditioned, response, often identical to that originally produced by the other, unconditioned stimulus. Although principles of classical conditioning had been noted by many Western scholars throughout the late nineteenth and early twentieth centuries, the discovery of classical conditioning is usually attributed to Ivan Pavlov, a nineteenth-century physiologist who came across classical conditioning while conducting research on canine digestion.To study digestion, Pavlov presented various types of food to dogs and measured their natural salivary response. Through this process, Pavlov noticed that with repeated testing, the dogs began to salivate before the food was presented, such as when they heard the footsteps of the approaching experimenter. Pavlov’s research team rigorously studied this process for decades, and this type of learning association came to be called classical or Pavlovian conditioning.While performing a variety of follow-up studies on this phenomenon, Pavlov found that when a classically conditioned salivary response was extinguished, the response gained in strength again after a period of approximately twenty minutes. Pavlov referred to this finding as spontaneous recovery. Although spontaneous recovery gradually increases with time after a conditioned response has been extinguished, conditioned responses do not generally return to full strength. Moreover, with repeated recovery/extinction cycles, the conditioned response tends to be less intense with each period of recovery. Recovery takes place even though there has not been any additional associations between the conditioned stimulus and the unconditioned stimulus. The ability of the conditioned stimulus was weakened but it was not eliminated. Although spontaneous recovery can be observed within a variety of domains, the phenomenon of spontaneous recovery can be particularly relevant in terms of human memory, as some types of memory, when seemingly forgotten, can unexpectedly return to human consciousness.