Classical Conditioning

Classical Conditioning

The basic phenomena of conditioning were first identified and analyzed in great detail in the laboratory of the Russian physiologist Ivan Pavlov (1849-1936). Pavlov's research carried out over a period of many years, represented a genuine intellectual revolution. This work was a brilliant application of the methods of natural science to problems of learning and behavior that had previously been untouched. The long-lasting significance of Pavlov's contribution can be seen in the fact that even today the technical vocabulary used by psychologists when they discuss learning is largely Pavlovian. This is all the more remarkable when you consider thatPavlov was not a psychologtst-and indeed, had little respect for, or sympathy with, those psychologists who were his contemporaries.
Pavlov had already won a Nobel prize (1904) for his earlier research on the philology of the digestive system. Pavlov's interest in conditioning -and his whole approach to it-was a logical outgrowth of his interest as a physiologist in the digestive glands. In his work on the digestive system Pavlov used dogs as experimental subjects. The salivary glands play an important role in the digestive process, and Pavlov developed a special operation to study their functining in intact dogs. This made it possible for him to collect and to measure precisely, the salivary secretions of his subjects. In this way he could examine the amount of salivary secretion that occurred when chemicals of various sorts were placed on the dog's tongue or when the dog ate, The saliva that flowed when food was placed in the dog's mouth was the sort of thing with which an experimental physiologist could deal routinely. This salivation response to food was regarded as a reflex; that is, a response automatically elicited by a particular stimulus (in this case the stimulus was food in the mouth).
Pavlov noted, however, that at times a dog would salivate a great deal even though no food was placed in its mouth. There was no good physiological reason for such salivation, but on the other hand it did not seem to occur at random. The ''nonphpiological'' salivary flow was very likely to occur if the dog smelled food, or heard the food bowls clattering in the laboratory kitchen, or caught sight of the attendant who usually fed it. This sort of salivary flew had been called ''psychic secretion," to distinguish it from the more ''respectable'' and orderly physiological salivary flow that Pavlov had been studying. This activity could therefore be considered a conditioned reflex, in that the dog had learned to salivate to stimuli besides food in the mouth; whereas tile response to food in the mouth was seen as a built-in reflex.
Pavlov decided to begin an experimental analysis of the elusive phenomena of ''psychic secretion." This was not conceived as a study of learning and behavior. To Pavlov, his studies of conditioned reflexes were a way of investigating the physiological functioning of the brain. Throughout his life Pavlov was less interested in the behavioral phenomena he so brilliantly analyzed than in the hypothetical brain processes which, he inferred, must be causing the behaviors.