What is Classical Conditioning?

Associate learning can be studied in the conditioned-response experiment originated by the Russian physiologist and Nobel Prize winner Ivan Pavlov.

White studying the relatively automatic reflexes associated with digestion, Pavlov noticed that a dog salivated not just when food was placed in its mouth but also at the mere sight of food. He interpreted the flow of saliva to food placed in the mouth as an unlearned response, or, as he called it, an unconditioned response.

But surely, he thought, the response to the sight of food has to be learned or conditioned response. Pavlov taught the dog to salivate to various signals, such as the onset of a light or tone, thereby proving to his satisfaction that a new stimulus-response association could be formed in the laboratory.

The association between the unconditioned stimulus and the unconditioned response exists at the start of the experiment and does not have to be learned.

The association between the conditioned stimulus and the conditioned response is learned. It arises through the pairing of the conditioned and unconditioned stimuli followed by the unconditioned response. The conditioned response resembles the unconditioned one but generally differs in some details.

Classical conditioning has also been used to study learning in human newborns 5-7 days old. When a puff or air is blown on the eye the natural response is to blink. If a tone is sounded immediately before the air puff, the newborn soon learns to associate the tone with the air puff and blinks on hearing the tone alone. Using this procedure, one can study learning in very young infants.

Classical conditioning process can be broken into two steps:

(a) Generalization:

When a conditioned response to a stimulus has been acquired, other similar stimuli will evoke the same response. A dog that learns to salivate to the sound of a tuning fork producing a tone of middle C will also salivate to higher or lower tones without further conditioning. The more nearly alike the new stimuli are to the original, the more completely they will substitute for it. This principle, called generalization, accounts for our ability to

react to novel situations in-so-far as they are similar to familiar ones. Careful study shows that the amount of generalization falls off in a systematic manner as the second stimulus becomes more and more dissimilar to the original conditioned stimulus.

A plotted relationship between stimuli and amplitude of a galvanic skin response learning is known as the gradient of generalization. Stimulus 0 denotes the tone to which the galvanic skin response (GSR) was originally conditioned. Stimuli +1, +2, and +3 represent test tones of increasingly higher pitch. Note that the amount of generalization decreases as the differences between the test tone and the training tone increases.

The conditioning of response to the meaning of a word (as opposed to the configuration or sound of a word) is called semantic conditioning.

(b) Discrimination:

A process complementary to gene is reaction to similarities, discrimination is reaction to differences. Conditioned discrimination is brought about through selective reinforcement and extinction.

Generalization and discrimination appear in ordinary behaviour. The young child who has learned to say “bow-bow” to a dog may understandably respond in like manner to a similar stimulus, such as a sheep. And a child on first learning the name “Daddy” may use it for all men. By differential reinforcement and extinction the response is finally narrowed to a single appropriate stimulus.