Behaviorism: the rise and fall of a discipline

Behavior theory, while still viable, no longer holds the dominance it once did in theoretical psychology.

The 20th century has seen the rise and, if not the fall, certainly the reappraisal of behaviorism in psychology. The roots of objective psychology, of which behaviorism is a part, go back to the late 19th century and the rise of experimental physiology and the transition from anecdotal methods to scientific observation in comparative psychology. The development of experimental physiology permitted the work on digestion by Ivan Pavlov and eventually to his work on conditioning.

The study of learning by psychologists like Hermann Ebbinghaus and G.E. Müeller also demonstrated the use of objective methods in psychological research. Edward L. Thorndike had an early interest in comparative psychology. As a student at Harvard, he carried out his classic experiments on trial and error learning in animals which later led to his "connectionism."

One of the results of this early experimentation was Thorndike's "law of effect," the idea that rewarded behaviors are increased in an animal's repertoire while punished behaviors are decreased. (Thorndike later replaced punishment with nonreward in his definition.)

But the founding of behaviorism as a movement is credited to John B. Watson, who, while a doctoral student with James R. Angell at the University of Chicago, carried out animal research in maze learning. To Watson, the study of consciousness became irrelevant in predicting the behavior of animals and even humans.

In his 1913 manifesto, "Psychology as the Behaviorist Views It," Watson claimed that the introspective psychology was unscientific because it did not deal with objective states. He rejected all subjective states such as sensation, imagery and thought unless they could be observed by others. His movement, called Behaviorism, would be a stimulus-response psychology, dealing only with the reactions of muscles and glands to stimulus situations.

Behaviorism grew slowly before World War I, but use of behavior in applications of psychology during the war led to many people becoming converts afterwards.

In 1935, S. Smith Stevens at Harvard called on psychologists to think of behavior operationally: to represent concepts in psychology in terms of the ways they are objectively found. Thus, hunger became the amount of time without food. Operational definitions would become deeply embedded in behavioral psychology.

About the same time, Clark Hull, like an Isaac Newton, sought to provide lawful mathematical relationships to describe the nature of behavior. His research and that of Kenneth Spence centered on conditioning and the growth of habits and the factors that govern them.

Another strain of behavior research called "purposivistic behaviorism" was carried out in the early 1930s by Edward C. Tolman. Having been exposed to aspects of Gestalt and other nonbehavioral fields, Tolman approached the learning process with the idea that the animal or human was viewing the solution as a whole rather than as incremental elements to be learned to gain success.

It was Tolman who in 1938 introduced the concept of "intervening variables" into the psychological scene and urged study of their relationship to independent and dependent variables.

B.F. Skinner represented yet another branch of behaviorism. Skinner's research was concerned with the experimental analysis of behavior, and specifically, the effect of reinforcement on behavior. While Pavlovians used "hard-wired" reflexes as the raw material for conditioning, Skinner was able to use any overt action of the organism, from the smile of a baby to working harder for a grade.

Perhaps Skinner's most significant contribution to conditioning was his work on partial reinforcement. He worked with "schedules of reinforcement" to study and manipulate behavior.

If Skinner moved behavior theory away from the physiology of the organism for explanation, Donald Hebb brought behaviorism into the physiology of the organism itself. Hebb was influential in establishing physiological psychology as part of behavior theory. He worked widely with behavioral physiological psychologists Karl Lashley and Robert M. Yerkes, as well as with the brain surgeon Wilder Penfield.

In 1949, Hebb introduced his theory of cell-assembly: a group of neurons clustered together functionally because of a past history of being stimulated together. The cells are capable of functioning together for a time as a closed unit. Cell assemblies that are activated at the same time may become organized into "phase sequences," which become the basic elementary or functional units of behavior.

By the 1940s and 1950s, behaviorism reigned supreme in American experimental psychology, moving into virtually every sphere in psychology, applied and theoretical. With it came an environmentalist view, emphasizing learning and experience over inheritance of traits. But, around 1965, the tide began to turn with the coming of the "cognitive revolution" in experimental psychology.

Just why behavior theory declined is complicated. Perhaps the extensions of behavior theory into issues of everyday life demonstrated in ways the laboratory could not that the extant behavior theories were overly simplistic and inadequate, particularly as they applied to human beings. Psychologists sought something more to explain the complexity of human conduct.

At the turn of the new century, behavior theory, while still viable, no longer holds the dominance it once did in theoretical psychology. Applications, such as behavior modification, have remained fruitful, although even in the clinical area, more cognitively oriented therapies and approaches are gaining favor.

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