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Article Outline
Introduction; Simple Forms Of Learning; Classical Conditioning; Operant Conditioning; Learning by Observation; Other Forms of Learning; Theories of Learning; Factors That Influence Learning Ability
Following his initial discovery, Pavlov spent more than three decades studying the processes underlying classical conditioning. He and his associates identified four main processes: acquisition, extinction, generalization, and discrimination.
The acquisition phase is the initial learning of the conditioned response—for example, the dog learning to salivate at the sound of the bell. Several factors can affect the speed of conditioning during the acquisition phase. The most important factors are the order and timing of the stimuli. Conditioning occurs most quickly when the conditioned stimulus (the bell) precedes the unconditioned stimulus (the food) by about half a second. Conditioning takes longer and the response is weaker when there is a long delay between the presentation of the conditioned stimulus and the unconditioned stimulus. If the conditioned stimulus follows the unconditioned stimulus—for example, if the dog receives the food before the bell is rung—conditioning seldom occurs.
Once learned, a conditioned response is not necessarily permanent. The term extinction is used to describe the elimination of the conditioned response by repeatedly presenting the conditioned stimulus without the unconditioned stimulus. If a dog has learned to salivate at the sound of a bell, an experimenter can gradually extinguish the dog’s response by repeatedly ringing the bell without presenting food afterward. Extinction does not mean, however, that the dog has simply unlearned or forgotten the association between the bell and the food. After extinction, if the experimenter lets a few hours pass and then rings the bell again, the dog will usually salivate at the sound of the bell once again. The reappearance of an extinguished response after some time has passed is called spontaneous recovery.
After an animal has learned a conditioned response to one stimulus, it may also respond to similar stimuli without further training. If a child is bitten by a large black dog, the child may fear not only that dog, but other large dogs. This phenomenon is called generalization. Less similar stimuli will usually produce less generalization. For example, the child may show little fear of smaller dogs. More from Encarta
The opposite of generalization is discrimination, in which an individual learns to produce a conditioned response to one stimulus but not to another stimulus that is similar. For example, a child may show a fear response to freely roaming dogs, but may show no fear when a dog is on a leash or confined to a pen.
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