Saturday, November 5, 2011

Skinner’s operant conditioning theory

SKINNER’S OPERANT CONDITIONING THEORY


By Miss Wilayat

                                (Power point presentation)

 

B.F. SKININER  (BIOGRAPHY)

      B.F. Skinner was born on March 20, 1904, in Susquehanna, Pennsylvania (America). He received his B.A. in English from Hamilton College in upstate New York. He was a psychologist, author, inventor, advocate for Social reform and Poet. He served as a Professor of Psychology at Harvard University from 1958 until his retirement in 1974. He invented his own Philosophy of Science called Radical Behaviorism and founded his own school of experimental research Psychology- the experimental analysis of behavior.

 SKINNER OPERANT CONDITIONING

          The concept of operant conditioning was developed by B.F. Skinner in 1938. Operant conditioning (or instrumental conditioning) is a form of learning in which the consequences of behavior produce changes in the probability of the behavior’s occurrence. Skinner chose the term operant to describe the behavior of an organism- the behavior operates on the environment, and the environment in turn operates on the behavior. The consequences are contingent, or dependent, on the organism’s behavior. For Example, a simple operant might be pressing a lever that leads to the delivery of food, the delivery of food is contingent on pressing the lever.

 

THE SKINNER BOX


    Skinner became a staunch supporter of positive consequences to mange behavior. He created colorful demonstrations of this principle to support his view point. For example, he taught Pigeons to play table tennis and navigate torpedoes.

BASIC PRINCIPLES OF OPERANT CONDITIONING

 REINFORCEMENT

      Reinforcement (reward) is a consequence that increases the probability that a behavior will occur. Reinforcement means “to strengthen”.

POSITIVE + NEGATIVE REINFORCER

    The events which strengthen a response are called reinforcers. Positive Reinforcement occurs when behavioral response, is followed by a pleasant Stimulus that rewards it.

     Here the frequency of response increases because it is followed by a stimulus, as for example the smile increasing talking. The same principle is at work when an animal trainer reaches a dog to “shake hands” by giving it a piece of food when it lifts its paw. In the Skinner box experiment, positive reinforcement is the rat pressing a lever and receiving a food reward.

 PRIMARY AND SECONDARY REINFORCEMENT

            Positive reinforcement can be classified as either primary or secondary reinforcement. The difference between the two focuses on a distinction between in born, unlearned, and learned aspects of behavior. Primary reinforcement involves the use of reinforcers that are innately satisfying that is they do not take any learning on organism’s part to make them pleasurable. Food, water, and sexual satisfaction are primary reinforcers.

          Secondary reinforcement acquires its positive value through experience; secondary reinforcers are learned or conditioned reinforcers. Hundreds of secondary reinforcers characterize our lives. For example, secondary reinforcers include such social situation as getting a pat on the back, praise etc.

 

            Negative Reinforcement occurs when behavioral response is followed by an unpleasant stimulus being removed. Here the frequency of a response increases because the response either removes a stimulus or involves avoiding the stimulus. For example, your father nags at you to clean out the garage. He keeps nagging. Finally you get tired of the nagging and clean out the garage. Your response (cleaning out the garage) removed the unpleasant stimulus (nagging).

 

PUNISHMENT

 

          Punishment is a consequence that decreases the probability that a behavior will occur. In punishment, a negative reinforcer is made contingent upon a response which typically had some prior source of strength. Some early studies by skinner (1938, P. 154) using a mild punisher (the lever slapped upward against the rat’s paw when it was pressed) came to the conclusion that punishment was a relatively ineffective means to produce any permanent change in behavior.

     What are some of the circumstances when punishment might effectively be used?

     Punishment can be considered when positive reinforcement has not been found to work.

 

     When the behavior that is being punished is viewed as more destructive than the punishment itself, then punishment is justified.

     For example, some children engage in a behavior that is dangerous to their well being, such as head banging, Punishment might reduce the behavior, it is always to reinforce an alternative behavior so that undesirable behavior does not replace the punished response (Santrock, 1989).

     Skinner believed that punishment is not especially effective in reducing the frequency of behavior and recommended positive reinforcement techniques as preferable. Punished individuals might learn to suppress the undesirable behavior rather than replace it with something more positive.

     When Punishment is used, desirable as well as well as undesirable behavior might be eliminated. For example, a child might stop interacting with other children altogether if he is slapped for biting another child.

            Negative reinforcement and punishment are easily confused because they both involve aversive or unpleasant stimuli, such as an electric shock or a slap in the face. To keep them straight, negative reinforcement increases the probability a response will occur, whereas punishment decreases the probability a response will occur.

      SCHEDULES OF REINFORCEMENT

     In most of life’s experiences, we are not reinforced every time we make a response, a student is not patted on the back each time she solves a problem a golfer, dose not win every tournament she enters.

     Schedules of reinforcement are “time tables” that determine when a response will be reinforced. There are two types of reinforcement schedules.

1. Continuous Reinforcement

    In continuous reinforcement, the desire behavior is reinforced every single time it occurs. Generally this schedule is best used during the initial stages of learning in order to create a strong association between the behavior and the response. Once the response if firmly attached, reinforcement is usually switched to a partial reinforcement schedule.

2. Partial Reinforcement

     In partial reinforcement, the response is reinforced only part of the time. There four schedules of partial reinforcement.

     i.     Fixed-ratio schedules are those where response is reinforced only after a specified number of responses. This schedule produces a high, steady rate of responding with only a brief pause after the delivery of reinforce.

     ii.    Variable-ratio schedules are those where a response is reinforced after an unpredictable number of responses. The schedule creates a high steady rate of responding. Gambling and lottery games are good examples of  a reward based on a  variable-ratio schedule.

n    Fixed internal schedules are those where the first response is rewarded only after specified amount of time has elapsed. This schedule cause high amount of responding near the end of interval, but much slower responding after the delivery of reinforcers.

iv. Variable interval schedules occur when response is rewarded after an unpredictable amount of time has passed. This schedule produces a slow, steady rate of response.  


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