The name of B. F. (Burrhus Frederic) Skinner has become virtually synonymous with behaviorism. By introducing the concept of "operant conditioning" (in the late 1930s), Skinner fundamentally transformed behaviorist approaches to experimental psychology. Operant conditioning is based on the fact that the behavior of organisms (including people) typically has environmental consequences and is explained in important part by reference to them. Its fundamental principle is that the probability of occurrence of a specified kind of behavior is a function of the environmental consequences of previous occurrences of behavior of the same type, most notably, that the probability increases if the previous occurrences have been followed by "reinforcement." Skinner, surpassing older behaviorist "stimulus-response" approaches, inaugurated an experimental research program aiming to discover the laws of operant conditioning and, thus, generalizations concerning the three-term relation: discriminative stimulus-behavior-reinforcement.

The earliest laws of operant conditioning include...