Friday, September 01, 2006

Behaviourist Approach

B.F Skinner (Operant Conditioning)

Skinner defined operant behavior as that behavior that is instrumental in achieving a desired goal. In fact, operant behavior also is known as instrumental behavior. Operant behavior refers to how people change or operate upon their environment to meet their needs. Operant conditioning is a learning process that is based on the consequences of behavior. Rewarded behaviors are likely to be repeated while punished behaviors are not.

Skinner's approach is centered in the operant conditioning method (also own as instrumental conditioning). Basically, the method is directed toward increasing or decreasing the frequency of certain existing behaviors. It also is used to teach or condition new behaviors and to unlearn old behaviors. Basically the method works by applying one of four possible consequences following the currence of a specific behavior:

Positive and Negative Reinforcement: Two of the consequences are designed to initiate or to increase the frequency of behavior: positive reinforcement and negative reinforcement. Just remember that the term reinforcement always refers to building up or strengthening a behavior. Positive reinforcement refers to the presentation of a positive or rewarding consequence following a desired behavior. For example, students could be granted free time for accumulating points for academic achievement and on-task behaviors. Negative reinforcement refers to the removal of a negative consequence following a desired behavior. For example, if students do well on their class project, they could be excused from taking the final examination (a definite negative consequence). To summarise; reinforcers can be either positive or negative. A positive reinforcer is a stimulus that increases the probability of a response occurring when it is added to a situation. A negative reinforcer has the same effect as a result of being removed from the situation. Negative reinforcers tend to be aversive stimuli (such as an electric shock or detention). Their effect, when removed or discontinued, is an increase in behavior. Positive reinforcers tend to be pleasant stimuli.

To understand these principles of learning Skinner used rats and pigeons in small boxes that allowed limited behaviours to occur and reinforcers or punishment given. In the Skinner box, food pellets are pleasant stimuli that serve as positive reinforcement when a lever is pressed. However, if a mild current were turned on in the electric grid that runs through the floor of the box, and if this current were turned off only when the rat depressed the lever, the current would be an example of an aversive stimulus serving as a negative reinforcer.

Reinforcers can be primary or generalised. A primary reinforcer is a stimulus that is naturally reinforcing—that is, that the organism does not have to learn that it is reinforcing. Primary reinforcers are ordinarily related to an unlearned need or drive: food, drink, or sex. Stimuli that satisfy these drives tend to be highly reinforcing for most organisms. They are referred to as positive stimuli. A generalized (secondary) reinforcer is a previously neutral stimulus that, through repeated pairings with other reinforcers in various situations, has become generally reinforcing for many behaviors. Prestige, money, and success are examples of extremely powerful generalized reinforcers.

Punishment and Extinction: The other two consequences are designed to stop or decrease the frequency of a behavior. Punishment refers to the presentation of something negative or the removal of something positive following an undesired behavior. For example, students could be required to repair damage they did to their school building. Extinction refers to the withholding of a reinforcing consequence following an undesired behavior. For example, when a student is seeking attention through disruptive behavior, attention can be withheld by ignoring the student or by removing the student's audience by isolating the student in a time-out room until the student is finished doing the disruptive behavior.

Skinner preferred to focus his attention on reinforcing appropriate behavior than punishing inappropriate behavior. He believed that punishment served to bring about short-term suppression of the misbehavior but did little to extinguish it on a permanent basis. Skinner also was concerned about the undesirable side effects of punishment, which include deteriorating relationships, revenge, anger, aggressiveness, anxiety, and fear.

To conclude, a classroom is in many ways like a gigantic Skinner box. It is engineered so that certain responses are more probable than others. For example, it is easier to sit at a desk than to lie on one, and it is easier to remain awake when sitting than when lying down. And at the front of a million classrooms stand those who are among the most powerful dispensers of childhood reinforcement—teachers. They smile or frown; they say "cool" or "thats awful"; they give high grades or low grades; occasionally they grant special favors; at other times they withhold or cancel privileges. By means of their use of reinforcement and punishment, sometimes deliberate and planned and sometimes quite unconscious, teachers shape the behavior of their students.

Practical Applications

Programmed Learning:

Dembo (1981) derives the following practical advice for teachers from Skinner's work. First, in teaching a new task, teachers should act so as to reinforce immediately rather than allowing a delay between student response and reinforcement. Secondly, reinforce appropraite learning behaviours in the early stages of a task. When learning is seen to occur, teachers should insist upon a more correct response before reinforcement and move gradually, but methodically, to intermittent reinforcement. Thirdly, teachers should not expect a perfect performance of a task by the student on the first occasion; rather teachers should attempt to reinforce students' steps in the direction of mastery. Finally, teachers should not reinforce in any way undesirable behaviour.

Establishing a schedule of reinforcement: Once a teacher has decided that s/he wishes to change the behaviour of their students using operant conditioning techniques, they have to establish a schedule of reinforcement. For example, continuous reinforcement means that a reward is given every single time the child exhibits the 'correct' response. This has the advantage that the child will learn very quickly to behave in a particular way. However, the fast rate of learning is balanced out by a fast rate of extinction, when the rewards are stopped, then the child very quickly ends the behaviour. An alternative technique is partial reinforcement, in this, the rewards are not given every single time, but maybe every other time or every third time, or even at random intervals in response to the correct behaviour. With this schedule, the rate of learning is much slower, but so is the rate of extinction; because the child has not got used to receiving a reward every time, when the rewards stop, they persevere with the behaviour in the hope that the reward will eventually come. In practice, formal reinforcement schedules often use a combination of continuous and partial reinforcement, by starting with rewarding every correct behaviour so that learning takes place quickly, then expecting more and more instances of the behaviour before offering the reward so that the child comes to depend less on the reinforcement.

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