The Story of Psychology

by Morton Hunt

  Another reason so many psychologists found behaviorism appealing was that by limiting themselves to visible behavior they could dispose of all those intractable questions about the mind that philosophers and psychologists had labored over for more than twenty-four hundred years. Behaviorists said that we not only cannot know what goes on in the mind, we don’t need to know in order to explain behavior. They often likened the mind to a black box containing unknown circuitry; if we know that when we push a particular button on it, the box will emit a specific signal or action, what is inside is of no consequence. Nor should what goes on in the mind even be discussed, since all talk about mental processes is tantamount to believing in some bodiless entity that runs the brain’s machinery—“the ghost in the machine,” as the English behaviorist philosopher Sir Gilbert Ryle derisively called it. (Equally derisive was the statement of an antibehaviorist: “The mere mention of the word ‘mentalism’ offends the sensibilities of a behaviorist in much the same way the word ‘masturbation’ offends polite company.”32)

  There were, moreover, deep-seated social and cultural reasons for the success of behaviorism. It appealed to the twentieth-century personality, especially in America, because it was practical; it sought not ultimate explanations but commonsense knowledge that could be put to use.

  At least one historian of behaviorism, David Bakan, has also linked its rise to the urbanization and industrialization of America; these social developments, he says, created an urge to master the incomprehensible and worrisome strangers all around us—exactly what behaviorism promised to help us do.33

  Bakan adds two other societal reasons for the success of behaviorism. First, World War I evoked hostility to German psychology, and behaviorism served as an up-to-date and available replacement. Second, behaviorism fit in with the endemic anti-intellectualism of America; it justified ignorance of the subtleties of mentalist psychology on the grounds that mental phenomena, being either illusions or unknowable, were not worth one’s time and effort.

  From the 1920s to the 1960s, behaviorism (or the more complex versions of it known as neobehaviorism) was the regnant force in American psychology and the model that it exported to the rest of the psychological world. Some psychologists still clung to older schools of thought, and a number of others, among them Freudians, developers of mental testing, child development psychologists, and Gestaltists, were concerned with mental processes, but on most campuses such people had to adapt their work and language to the behaviorist paradigm. Gregory Kimble, a historian of behaviorism, says, exaggerating only a little, “In midcentury American psychology, it would have cost a career to publish on mind, consciousness, volition, or even imagery,” since to use such terms signified that one was a mentalist who believed in outdated, subjective, and mystical concepts.34

  In consequence, much of the research conducted between 1920 and the 1960s dealt with minute, undeniably objective but not very enlightening topics. A few representative titles from the Psychological Bulletin and the American Journal of Psychology in 1935 were:

  “Influence of Hunger on the Pecking Responses of Chickens”

  “Comparison of the Rat’s First and Second Explorations of a Maze Unit”

  “The Use of Maze-Trained Rats to Study the Effect on the Central Nervous System of Morphine and Related Substances”

  “Differential Errors in Animal Mazes”

  “Circuits Now Available for the Measurement of Electrodermal Responses”

  Even when human beings were the experimental subjects, the topics and methods were constrained by behaviorist doctrine. Some typical titles from the American Journal of Psychology in 1935 were:

  “The Reliability of the pH of Human Mixed Saliva as an Indicator of Physiological Changes Accompanying Behavior”

  “A Comparison of the Conditioning of Muscular Responses Which Vary in Their Degree of Voluntary Control”

  “Experimental Extinction of Higher Order Responses”

  “The Galvanic Skin Reflex as Related to Overt Emotional Expression”

  “Over-Compensation in Time Relationships of Bilateral Movements of the Fingers”

  The authors of these and similar studies were not really interested in the pecking behavior of chickens or the pH of human saliva but in learning—the acquisition of behavioral responses to different kinds of stimuli. Learning was the central concern of American psychology during the behaviorist era, the assumption being that almost all behavior could be explained by S-R learning principles.35 An equally important assumption was that these principles held true of all sentient creatures, much as the principles of valence are true of all elements in chemical compounds. What one learned from chickens, cats, dogs, and especially rats applied to human beings.

  Rats were the favorite experimental animal because they were relatively cheap, small, easy to handle, and fast-maturing. Countless thousands of them served the cause of research by learning to run mazes, operate levers or push buttons to get food, jump at doors of different colors, depress a bar to turn off an electric current that was making their feet tingle, and a host of other tasks. There was nothing frivolous about these experiments; they were aimed at the discovery of important universal laws of behavior. A few examples:36

  —A rat is placed at the start of a simple maze that includes six choice points (each choice point is a T, one branch being a blind alley, the other an alley that continues) and ends at the goal box. The rat begins exploring and sniffing about, and runs a little; it goes into a blind alley, turns back and runs the other way, and after making three wrong choices and three right ones reaches the goal box— and is lifted out and, after a brief rest, put back in the start box. On its seventh run it finds a food pellet at the goal; the rat sniffs it, then bolts it down. Another rat gets the same training but without any food reward, not even on the final run.

  For a week both rats get the same training every day. By the end of the week the first rat knows the route perfectly and races through the maze, making no mistakes; the second rat still makes as many errors as ever. But finally the second rat gets a food reward at the end of its run—and, remarkably, on the next trial makes no errors. It learned as much from one rewarded trial as the other rat learned in a week. The experiment demonstrates the operation of two principles: reward produces learning, exemplified by the first rat’s behavior; and lacking reward, there may be latent learning, exemplified by the second rat’s behavior. (Learning takes place in some sense when there is no reward but becomes activated as soon as a reward is associated with the “right” behavior.)

  What has this got to do with human behavior? Any teacher can tell you. A child practicing drawing or any other skill may make little progress until the teacher has a moment to say something encouraging or complimentary; then, suddenly, the child shows improvement. Similarly, a novice at flying may make a dozen bumpy landings, finally “grease one in” half by accident, winning praise from his instructor, and from then on make landings as if he had at last “got the idea.”

  —One at a time, a number of rats are put in the start box of a simple T-shaped maze. At the end of the right-hand branch is a white door behind which is a bit of cheese; at the end of the left-hand branch is a black door behind which is a metal grid floor that gives the rat’s feet a mild but unpleasant shock. The rats learn, after a while, to turn right and push through the white door. But once they’ve learned, the experimenter switches the situation. Now the white door and food are at the end of the left branch, the black door and electrified grid at the end of the right branch. The rats turn right, get shocked, and soon learn to turn to the left.

  Once again the diabolic experimenter reverses things, but now the rats learn almost immediately; they have come to associate reward and punishment with the colors of the doors, not their direction. The experiment revalidates Pavlov’s principle of discrimination, the determination of the rewarding cue in a two-cue situation.

  Does this apply to humans? Of course. A novice at gardening gets only a meag
er crop of tomatoes but sees that his neighbor, who plants a different variety in a sunnier location, gets a bumper crop. The novice tries the neighbor’s variety the next year; still no luck. He realizes that the number of hours of sunshine must be the critical factor, fells some trees to get more sunshine, and is successful.

  —Another T-maze in which rats learn to turn to the right. This time there is no punishment for choosing the left branch but merely a lack of reward. Some rats are lucky; they find a reward every time they choose the right side. Others are unlucky; they find food there only once every four times. The unlucky rats learn far more slowly than the lucky rats to choose the right-hand branch. The experiment demonstrates that partial reinforcement is less effective in learning than is continual reinforcement.

  But now the experimenter changes things; there is no reward at either branch for either group. What happens? Oddly, the rats who had previously been lucky lose their conditioning rapidly and begin to alternate their choices, while the ones who were rewarded only every fourth time continue to choose the right branch for a long while. The experiment has demonstrated the partial reinforcement effect: the higher the creatures’ expectations, the more disruptive a change in the situation; with lower expectations, their learned behavior is more stable when change occurs.

  A human analogue: A highly efficient employee has had a generous raise every year; in a year of poor income for the company, he gets only a modest raise, loses his drive, starts taking longer lunches, leaves promptly at 5:00 p.m., and calls in sick now and then. A less capable employee, who has only occasionally gotten a raise bigger than a cost-of-living adjustment, gets only a cola in the poor year; his commitment to his job is unaffected, because, not expecting much, he does not interpret the lack of bonus as a change in the system.

  Two Great Neobehaviorists: Hull and Skinner

  As the above experiments show, behaviorists were enlarging their theory and methodology far beyond Watson’s formulations. He had described behavior in simplistic terms as “the total striped and unstriped muscular and glandular changes which follow upon a given stimulus,”37 a view later dubbed “muscle-twitch psychology.” For a while, his followers stuck to this view; as one of them, Walter Hunter, wrote in 1928, “All behavior seems to be a combination, more or less complex, of the relatively simple activities of muscles and glands.”38

  Yet to say anything meaningful about complex forms of behavior, it was necessary to see them intact, as acts with an identity and meaning. A bird building a nest is not just an organism responding to X number of stimuli with X number of reflexes; it is also a bird building a nest—an intricate kind of behavior with a goal. As one behaviorist, Edwin Holt, said in 1931, behavior is “what the organism is doing”—hunting, courting, and so on—an organized entity, and not merely the string of reflexes of which that entity is constructed, not just “an arithmetical sum, related only by the and or plus relation.”39

  But Holt refused to attribute purpose to the creature itself; that would have implied the influence of a mind that looked ahead to the goal and set out to reach it. Rather, he ascribed the purposiveness of complicated behaviors to the process by which S-R units were combined: the creature’s seeking or avoiding, at each step, assembled S-R units in such a way that the assemblage appeared to be purposive behavior. It was a vague and unsatisfying formulation, but it went as far as any orthodox behaviorist could go.

  A more important development was the neobehaviorist effort of Clark L. Hull (1884–1952) of Yale University to make behaviorism a quantitatively exact science modeled after Newtonian physics. Hull, who had started out to be a mining engineer, suffered an attack of polio and remained partly crippled. He switched to psychology, since it was less likely to involve heavy physical activity, but the engineering training carried over, and he set out to develop a kind of calculus of behaviorism. As he wrote in his autobiography:

  [I] came to the definite conclusions around 1930 that psychology is a true natural science; that its primary laws are expressible quantitatively by means of a moderate number of ordinary equations; that all the complex behavior of single individuals will ultimately be derivable as secondary laws from (1) these primary laws together with (2) the conditions under which behavior occurs; and that all the behavior of groups as a whole, i.e., strictly social behavior as such, may similarly be derived as quantitative laws from the same primary equations.40

  Hull’s central concept was a familiar one: behavior consists of sets or chains of linked habits, each of which is an S-R connection that developed as a result of reinforcement. This was his version of Thorndike’s Law of Effect. What was new about Hull’s work was his postulation of a number of factors, each of which, he held, enhances, limits, or inhibits the formation of such habits, and his development of equations by which one could calculate the exact effect of each of those factors.

  They included the level of the creature’s drive (a hungry rat has a stronger drive to food than a sated rat); the strength of the reinforcement (expressed in such terms as “5 grams of a standard food”); the number of times a stimulus had been followed by reinforcement; the degree of “need reduction” achieved by each reinforcement; the degree of “drive reduction” (drives are fueled by needs) due to fatigue and the length of time between one trial and the next trial; and so on and on. As Edwin Boring later said, with consummate understatement, it was a “ponderous” theory.41

  An example: By means of the following equation one can calculate the extent to which any given number of repetitions of a reinforced act increases the strength of the learned habit:42

  The equation says that the strength of the learned habit depends on the number of reinforced trials (N), the relationship between the afferent and efferent nerve impulses in the specific act (SHR), the physiologically maximum strength of that particular habit (M) minus—well, it goes on and on.

  Hull’s work was a major attempt to model neobehaviorist psychology on the physical sciences and thereby have it achieve intellectual respectability. His calculus of learning, appearing piecemeal during the 1930s and in systematic form in his Principles of Behavior (1943), was greatly admired and hugely influential. In the late 1940s and the 1950s thousands of master’s theses and doctoral dissertations were based on one or more of his postulates; he became the most frequently cited psychologist in the literature of psychological research and the leading figure in the psychology of learning.43

  But during the 1960s, the unwieldiness of his theory and the dwindling of behaviorism’s status made Hull’s name and work fade rapidly from sight. By 1970 he was rarely quoted, and today there is virtually no research based on his theory. When Hull died, in 1952, he seemed assured of scientific immortality; now he is a figure of minor historical interest, and few young psychologists and very few people outside the profession know his name.44

  B. F. Skinner (1904–1990), another leading neobehaviorist, had a very different fate. He became, and remained until his death at eighty-six, the best-known psychologist in the world,45 and his ideas are in wide use today in psychological research, education, and psychotherapy.46

  So he must have been one of the great contributors to humankind’s quest for self-understanding, right?

  Far from it.

  Human self-understanding, at least as sought by philosophers and psychologists for so many centuries, was no part of Skinner’s aim or contribution. Throughout his long life he held fast to his extreme behaviorist view that “subjective entities” such as mind, thought, memory, and reasoning do not exist but are only “verbal constructs, grammatical traps into which the human race in the development of language has fallen,” “explanatory entities” that themselves are unexplainable.47 Skinner’s goal was not to understand the human psyche but to determine how behavior is created by external causes. He had no doubt about the correctness of his views; as he wrote in a short autobiography—he also wrote a three-volume one—“[Behaviorism] may need to be clarified, but it does not need to be argued.”48


  Nor did he add much to psychological theory; he considered theories of learning unnecessary and claimed not to have one. Such theory as he did hold can be summed up in the statement that everything we do and are is determined by our history of rewards and punishments; the details of the theory, as he developed them through research, consisted of such principles as the partial reinforcement effect described above, concerning the circumstances that cause behavior to be acquired and those that cause it to be extinguished.

  What, then, made him so well known?

  Like Watson he was by nature a controversial man, a provocateur, and a superb publicist. On his very first TV appearance he posed a dilemma originally propounded by Montaigne—“Would you, if you had to choose, burn your children or your books?”—and said that he himself would burn his children, since his contribution to the future would be greater through his work than through his genes.49 Predictably, he elicited outrage—and many invitations for further appearances.

  At other times he seemed to take pleasure in offending thoughtful people by deriding the terms in which they talked about and comprehended human behavior:

  Behavior…is still attributed to human nature, and there is an extensive “psychology of individual differences” in which people are compared and described in terms of traits of character, capacities, and abilities. Almost everyone who is concerned with human affairs … continues to talk about human behavior in this prescientific way.50

  He consistently pooh-poohed the effort to understand the inner person:

  We do not need to try to discover what personalities, states of mind, feelings, traits of character, plans, purposes, intentions, or other perquisites of autonomous man really are in order to get on with a scientific analysis of behavior… Thinking is behaving. The mistake is in allocating the behavior to the mind.51