The process of closely associating a neutral stimulus with one that evokes a reflexive response so that eventually the neutral stimulus alone will evoke the same response.

Classical conditioning is an important concept in the school of psychology known as behaviorism, and it forms the basis for some of the techniques used in behavior therapy.

Classical conditioning was pioneered by the Russian physiologist Ivan Pavlov (1849-1936) in the 1890s in the course of experiments on the digestive systems of dogs (work which won him the Nobel Prize in 1904). Noticing that the dogs salivated at the mere sight of the person who fed them, Pavlov formulated a theory about the relationship between stimuli and responses that he believed could be applied to humans as well as to other animals. He called the dogs' salivation in response to the actual taste and smell of meat an unconditioned response...