Skinner is regarded as the father of Operant Conditioning, but his work was based on Thorndike’s (1898) law of effect. According to this principle, behavior that is followed by pleasant consequences is likely to be repeated, and behavior followed by unpleasant consequences is less likely to be repeated. He introduced a new term into the Law of Effect - Reinforcement. Behavior which is reinforced tends to be repeated (i.e., strengthened); behavior which is not reinforced tends to die out-or be extinguished (i.e., weakened). Skinner (1948) actually studied operant conditioning by conducting experiments using animals which he placed in a 'Skinner Box' which was similar to Thorndike’s puzzle box.

Skinner identified three types of responses, or operant, that can follow behavior:

• Neutral operants: responses from the environment that neither increase nor decrease the probability of a behavior being repeated.

• Reinforcers: Responses from the environment that increase the probability of a behavior being repeated. Reinforcers can be either positive or negative.

• Punishers: Responses from the environment that decrease the likelihood of a behavior being repeated. Punishment weakens behavior.

I am certain that we can all think of examples of how our own behavior has been affected by reinforcers and punishers. As a child you probably tried out a number of behaviors and learned from their consequences.For example, if when you were younger you tried smoking at school, and the chief consequence was that you got in with the crowd you always wanted to hang out with, you would have been positively reinforced (i.e., rewarded) and would be likely to repeat the behavior. If, however, the main consequence was that you were caught, caned, suspended from school and your parents became involved you would most certainly have been punished, and you would consequently be much less likely to smoke now.