The acquisition phase is the initial learning of the conditioned responsefor 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 stimulusfor example, if the dog receives the food before the bell is rungconditioning seldom occurs.
Shaping is a reinforcement technique that is used to teach animals or people behaviours that they have never performed before. In this method, the teacher begins by reinforcing a response the learner can perform easily, and then gradually requires more and more difficult responses. For example, to teach a rat to press a lever that is over its head, the trainer can first reward any upward head movement, then an upward movement of at least one inch, then two inches, and so on, until the rat reaches the lever. Psychologists have used shaping to teach children with severe mental retardation to speak by first rewarding any sounds they make, and then gradually requiring sounds that more and more closely resemble the words of the teacher. Animal trainers at circuses and theme parks use shaping to teach elephants to stand on one leg, tigers to balance on a ball, dogs to do backward flips, and killer whales and dolphins to jump through hoops. Extinction
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.Extinction As in classical conditioning, responses learned in operant conditioning are not always permanent. In operant conditioning, extinction is the elimination of a learned behaviour by discontinuing the reinforcer of that behaviour. If a rat has learned to press a lever because it receives food for doing so, its lever pressing will decrease and eventually disappear if food is no longer delivered. With people, withholding the reinforcer may eliminate some unwanted behaviours. For instance, parents often reinforce temper tantrums in young children by giving them attention. If parents simply ignore the child's tantrums rather than reward them with attention, the number of tantrums should gradually decrease. Generalization
After an animal has learned a conditioned response to one stimulus, it may also respond to similar stimuli without further training. If a large black dog bites a child, the child may fear not only that dog, but also 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.Generalization and discrimination Generalization and discrimination occur in operant conditioning in much the same way that they do in classical conditioning. In generalization, people perform a behaviour learned in one situation in other, similar situations....