>> Tuesday, April 24, 2012
CLASSICAL Conditioning and INSTRUMENTAL Conditioning
Classical conditioning involves the association of an unconditioned and a conditioned stimulus in such a way that the conditioned stimulus elicits unconditioned response. There is the formation or strengthening of an association between a conditioned stimulus in a controlled relationship with an unconditioned stimulus that originally elicits that response. Classical conditioning has revealed facts concerning conditions of acquisition, extinction, generalization and discrimination. Once a conditioned response is established to a stimulus of a certain kind, the response will also occur to stimuli which are similar to the original stimulus. This is stimulus generalization. No learning occurs unless there is generalization. No two stimuli or stimulus situations are exactly alike. They must be treated as if they were exactly alike in order to elicit the same response.
Discrimination refers to eliciting different responses to two different stimuli. A dog, trained to withdraw a paw from an electric grid at the sound of a tone, will learn in time that he need not move his paw at the sound of a tone very slightly different in pitch. The dog will learn this discrimination if one tone is consistently reinforced while another is not.
Responses that are no longer reinforced tend to disappear from the organism’s repertoire of behavior. This is called extinction. Pavlov’s dog will not salivate at all times at the sound of a buzzer. If the buzzer is presented time after time without being paired with meat, extinction will occur.
Spontaneous recovery refers to the return of a conditioned response, following experimental extinction, after periods of no reinforcements. If the buzzer is sounded many times without presenting any food, the dog will reach a situation wherein it will ignore the buzzer. Although there will be times when the dog would salivate again at the sound of the buzzer. Studies have shown that once a conditioned response is established, it never completely disappears from the behavioral repertoire of an organism. After periods of rest or disuse, a conditioned response often reappears. If there is no reinforcement, it will extinguish again. Classical conditioning requires the association of two stimuli, with one of them gradually acquiring a significance it did not possess before.
Instrumental conditioning involves the selection of a response from among a series of responses. It needs the strengthening of a stimulus-response association by following the response with a reinforcing stimulus.
Instrumental conditioning (Operant Conditioning) is another kind of simple learning. It involves a selection from many responses of the one that habitually will be given in a stimulus situation. Instrumentally conditioned response states that the behavior of the animal in the learning situation is the basis of reinforcement. The organism gets nothing until he emits the desired response. Instrumental conditioning was first tried by EDWARD L. THORNDIKE (1898) using a puzzle box served as the instrument that elicited the reinforced behavior of the cat.
There are four (4) kinds of instrumental conditioning. They are all similar in that the learned response is instrumental in getting the organism biologically ahead. The simplest kind is called primary reward conditioning where the learned response is instrumental in obtaining a biologically significant reward, such as a pellet of food or an amount of water. Escape conditioning is one where the organism learns a response that is instrumental in getting out of a place one prefers not to be in. Avoidance conditioning is a kind of learning where a response to a cue is instrumental in avoiding a painful experience. Secondary reward conditioning is where there is instrumental behavior to get a stimulus which has no biological utility itself but which has in the past been associated with a biologically significant stimulus.
In recent years, device known as SKINNER box, named after B. F Skinner, has been widely used in laboratory studies. A fully equipped Skinner box is a device containing a bar to press, string to pull, a button to peck or some other stimulus which, if appropriately dealt with, automatically supplies the animal with a measured amount of food.