Burrhus Frederic "B. F." Skinner was an American psychologist, behaviorist, author, inventor, and social philosopher. He was the Edgar Pierce Professor of Psychology at Harvard University from 1958 until his retirement in 1974.
Skinner invented the operant conditioning chamber, also known as the Skinner Box. The box had a lever and a food tray, and a hungry rat could get food delivered to the tray pressing the lever. Skinner observed that when a rat was put in the box, it would wander around, sniffing and exploring, and would usually press the bar by accident, at which point a food pellet would drop into the tray. After that happened, the rate of bar pressing would increase dramatically and remain high until the rat was no longer hungry. He was a firm believer of the idea that human free will was actually an illusion and any human action was the result of the consequences of that same action. If the consequences were bad, there was a high chance that the action would not be repeated; however if the consequences were good, the actions that lead to it would be reinforced. He called this the principle of reinforcement.
He innovated his own philosophy of science called radical behaviorism, and founded his own school of experimental research psychology—the experimental analysis of behavior. His analysis of human behavior culminated in his work Verbal Behavior, as well as his philosophical manifesto Walden Two, both of which have which have recently seen enormous increase in interest experimentally and in applied settings. Contemporary academia considers Skinner a pioneer of modern behaviorism along with John B. Watson and Ivan Pavlov.