Burrhus Frederic Skinner: Psychologist

1904-1990
Theology: Behaviorism
His basis of behaviorism was that humans and animals have certain behavioral responses to external stimuli. He claims that humans and animals learn as a result of their responses to their environment.
Skinner's theory is formed from the idea of operant conditioning. In this, the human, or animal, begins in a normal mode of action. It is simply doing what it normally does, or is "operating." To condition the operant's behavior, there must be the influence of a reinforcer. Skinner calls this a reinforcing stimulus. The reinforcer, or award, has the effect of changing the behavior level of the operante, making it different from before the influence of the reinforcer. This condition, as he states, is followed by a consequence that modifies the organisms tendency to repeat a certain behavior in the future.
Burrhus Skinner applied his theory specifically to the conditioning of a rat. The rat was placed in a "Skinner Box",or a special cage, that had a foot pedal on one side and an entry door on the other for the entrance of a food pellet. The rat would step on the foot pedal and be rewarded with one food pellet. After accomplishing this task a few times, the rat learned that a reward was granted every time the pedal was compressed. Soon the rat was hastly retreiving pellets. When Skinner eliminated the supply of pellets, and the rat was unable to receive his reward, within a few attempts the rat refused to continue compressing the pedal.
Summary
Burrhus Skinner developed the theory that external stimuli effect the behavior of organisms. His experiment with the rat resulted in positive feedback that his theory was correct. Organisms react to the stimuli of their environment.