The Story of Psychology (53 page)

But since one teacher cannot simultaneously provide reinforcement to a roomful of children, new textbooks would have to be written in which questions and answers were presented one by one, each taking a short step toward mastery of the subject and each permitting children to reward themselves immediately by uncovering the answer. Skinner also developed teaching machines for operant self-instruction by comparable means; the mechanical models were a fad for a time, then dropped out of use, but today, computer-based self-instruction with immediate reinforcement is widely used by schools, businesses, and elder-care centers, among others.

For some years the programmed learning movement had a major influence on teaching; courses and course materials designed to teach through operant conditioning were in use in a large proportion of grade schools and colleges in America, and in many schools in dozens of other countries. But eventually educators recognized that the atomistic methods of programmed instruction provide only part of what human
beings need; they also need holistic, hierarchical thought structures. And later research showed that in human beings delayed reinforcement often has better results than immediate reinforcement; thinking about one’s responses may lead to more learning than quickly responding and getting an answer.
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Finally, the observation of other people’s behavior, a highly effective form of learning for humans, even if not for cats, involves no immediate reinforcement. Still and all, Skinner’s doctrine of immediate reinforcement has proven useful, is familiar to most teachers, and is incorporated into many curricula and grade school textbooks.

Skinner also had a measurable effect on the treatment of mental and emotional disorders. It occurred to him that a system of tiny rewards for tiny changes from sick acts toward healthy ones might reshape the patient’s behavior. Beginning in the late 1940s, he and two of his graduate students made the first experimental trials of what came to be known as behavior modification. They set up lever-pressing stations at a state mental hospital near Boston; psychotic patients received candy or cigarettes for operating the machines in an orderly fashion. Once that worked, the therapists gave tokens to patients for appropriate behavior, such as voluntarily attending meals, grooming themselves, and helping with housekeeping tasks. The tokens could be exchanged for candy, cigarettes, or privileges like choosing a dining companion, talking to a physician, or watching TV.
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The rewarding of desired behavior in deeply disturbed people often worked. One depressed woman would not eat and was in danger of dying of starvation, but she seemed to enjoy visitors and the TV set, radio, books and magazines, and flowers in her room. The therapists moved her into a room devoid of all these comforts, and put a light meal in front of her; if she ate anything at all, one of the comforts was temporarily restored. The therapists gradually withheld the rewards unless she ate more and more. Her eating improved, she gained weight, and within two months she was released from the hospital. A follow-up eighteen months later found her leading a normal life.
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The behavior modification movement spread to a number of mental hospitals and reform schools. Psychiatrists and psychologists now consider it a useful component of their therapies for severely disordered patients, though a costly one in terms of time and staff effort. Behavior modification is also used by many psychotherapists in the treatment of less severe problems, like smoking, obesity, shyness, tics, and speech problems. It is a specialized technique within the field of behavior therapy,
most of which is based on Pavlov-type conditioning rather than on Skinner’s behavior modification.

Skinner’s best-known work,
Walden Two
, has not remade American society or even part of it, but it undoubtedly has influenced the thinking and social concepts of its millions of readers. Only one effort has been made to create an actual utopia on the
Walden Two
model: Twin Oaks Community in Louisa, Virginia, a commune founded by eight people in 1967. After surviving many rocky years, it has grown to a population of eighty-five adults and fifteen children. While still modeled administratively on
Walden Two
, the commune long ago gave up the effort to define ideal behavior and to shape one another’s behavior through methods of Skinner reinforcement.
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Skinner was sometimes self-deprecating about his impact on the world. “In general,” he once said, “my effects on other people have been far less important than my effects on rats and pigeons—or on people as experimental subjects.” That was probably not meant to be taken seriously. What he did mean seriously was the following remark: “I was never in any doubt as to [my work’s] importance.” And he added, on a characteristically perverse note: “When it began to attract attention, I was wary of the effect rather than pleased. Many notes in my files comment on the fact that I have been frightened or depressed by so-called honors. I forgo honors which would take time away from my work or unduly reinforce specific aspects of it.”
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As behaviorist research accumulated, it became evident to all but the most dedicated adherents of the theory that rats and other laboratory animals frequently acted in ways that the theory could not explain.

For one thing, their behavior often failed to conform to supposedly universal principles of conditioning. “Pigeon, rat, monkey, which is which? It doesn’t matter,” Skinner had written
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—but it did matter. Researchers could easily train a pigeon to peck at a disk or a key for food but found it almost impossible to train the bird to flap its wings for the same reward. They could easily teach a rat to press a bar for food but could get a cat to do so only with great difficulty. A rat given sour blue water to drink, followed by a nauseating drug, would thereafter shun sour water but willingly drink blue water; a quail, given the same treatment, would shun blue water but drink sour water. These and scores of
comparable findings forced behaviorists to admit that each species has its own built-in circuitry that enables it to learn some things easily and instinctively, others with difficulty, and still others not at all. The laws of learning were far from universally applicable.
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A more serious flaw in behaviorist psychology was that experimental animals kept acting in ways that could not be explained by the neat rate-of-response curves. Many researchers had found, for instance, that at the beginning of an extinction trial an animal would respond to the stimulus with greater vigor than it had during a long series of reinforcements. A rat that had been getting a food pellet each time it pressed a bar would, if no pellet emerged, press the bar with extra force again and again, although according to strict behaviorist theory the absence of the reward should have weakened the response, not strengthened it.
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But of course human beings do the same thing. When a vending machine fails to deliver, the customer pulls or pushes the lever harder a few times, or even hits or kicks the machine, either expressing frustration or acting on the thought that something is jammed and needs an extra jolt. There was no place in behaviorist theory for such internal processes, particularly not for thinking about a problem, yet a number of behaviorists noticed that their rats sometimes behaved as if they were indeed doing rudimentary purposive thinking.

One leading researcher who was aware of this was Edward Chace Tolman (1886–1959), an eminent contemporary of Hull’s and a leading neobehaviorist of the 1930s and 1940s. He observed that after a rat had run a maze a few times, it would pause at a point of decision, look this way and that, take a few steps, and perhaps turn back, all before making its choice and going on. In his presidential address to the APA in 1938, Tolman said it seemed clear that the rat was performing “vicarious trial and error” in its head. “Anthropomorphically speaking,” he added, “it appears to be a ‘looking before you leap’ sort of affair.”
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That was only one of many bits of rat behavior that Tolman concluded could be explained solely in terms of processes going on in the rat’s head. Years earlier, he and a colleague had built a simple maze with three routes to the goal box. The shortest was a straight path from the start box to the goal box; the second, a little longer, made a short loop to the left, then rejoined the straight path partway toward the goal box; and the third, the longest, made a long loop to the right, then rejoined the straight path close to the goal box. In a series of trials the rat, as behaviorist theory predicted, found its way to the food by all three routes but learned to take the shortest, since that was the most easily established habit.

Tolman then put a barrier across the straight path halfway to the goal so that the rat could reach it only by the longest route. According to theory, when the rat ran down the straight path and came up against the barrier, it should have turned back and tried the next most easily established habit—the medium-length route—but it immediately took the long route. To Tolman this suggested that the rat had built up a sort of mental map of the entire maze and “realized” that the barrier blocked all but the longest route.
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Tolman conducted many similar experiments, most of them far more complicated, and all of which supported his belief that “something like a field map of the environment gets established in the rat’s brain.” Standard behaviorist theory, he said, offered only a partial explanation of maze learning: “We agree… that the rat in running a maze is exposed to stimuli and is finally led as a result of these stimuli to the responses which actually occur. We feel, however, that the intervening brain processes are more complicated, more patterned, and often, pragmatically speaking, more autonomous than do the stimulus-response psychologists.”
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These studies led Tolman to propound a theory he called “purposive behaviorism.” Its essence was that rats act not as automata, developing habits solely according to the number and kind of stimuli they experience, but as if, in addition, they are influenced by their own expectations, their knowledge of what leads to what in a given situation, their goals, and other internal processes or states.
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As one orthodox behaviorist derisively said, Tolman’s rats were “buried in thought.”
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Tolman called these internal factors “intervening variables” (they intervened between stimulus and response) and insisted that they were compatible with behaviorism. “For the behaviorist,” he wrote, “‘mental processes’ are to be identified and defined in terms of the behaviors to which they lead. [They are] naught but inferred determinants of behavior… Behavior and these inferred determinants are both objective, defined types of entity.”
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It was a valiant effort to remain faithful, but Tolman had, willy-nilly, breached the dike of behaviorism and let in a trickle of mind. In time it would be a flood.

If reward and repetition only partly explain rat behavior, they give an even more limited account of the determinants and workings of human behavior. Consider memory, for example. Behaviorists portrayed it in purely mathematical terms: the more trials and reinforcements, the
greater the rewards, the closer in time the S and the R, the more certain it is that the S will produce the R. If the stimulus is the question “What comes after five?,” the response is “six.” If the stimulus is the question “What is your phone number?,” the answer is a sequence of seven digits (ten if you include the area code). The first digit is the response to the question but is also the stimulus that produces the response of the second digit, and so on, in a chain of associative links.

But even at the height of the behaviorist era, psychologists knew that human memory was more complicated than that. For one thing, we “chunk” some information: we remember area codes, for instance, as units, not as a series of linked responses. For another thing, we have different kinds of memory: we learn some phone numbers only for a moment—we look them up, hold them in “short-term memory” until we dial, and then instantly forget them, but make others a part of our “long-term memory” (the vast stockpile of stored knowledge we draw on as needed). Some things require inordinate amounts of repetition and reward to become fixed in memory (many people can’t seem to remember their own Social Security number, though they’ve looked it up scores of times); other things (the exorbitant price we paid for dinner at a particular restaurant, our baby’s first words) remain indelibly fixed in memory after only a single experience. These and many other characteristics of human memory cannot be explained by the confined and rigid formulas of behaviorism.

Throughout the behaviorist era, some psychologists continued to explore, in broader and deeper terms, not only human memory but a number of the psychological phenomena that behaviorism had ignored, like perception, motivation, personality traits, reasoning, problem solving, creativity, child development, the interplay of hereditary tendencies and experience, and interpersonal relations. Gradually, the new data gathered about these subjects, and the questions those data raised that behaviorism could not answer, prepared the way for what Thomas Kuhn, in his famous analysis of scientific revolutions, called a “paradigm shift”—a relatively abrupt switch to a new theory encompassing and making sense of a large accumulation of data that could be accounted for only with difficulty, if at all, by the reigning theory.
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Meanwhile, research in a number of other fields was beginning to cast new light on the workings of the mind. From anthropology came studies of how preliterate peoples think; from psycholinguistics came accounts of how human beings acquire and use language; and from computer science came a wholly new way to conceive of thinking—as
information processing, proceeding step by step like a computer program.

The convergence of all these forces achieved intellectual critical mass during the 1960s, resulting in a knowledge explosion and a new conception of psychology. The former cognitive specialties within psychology regained their status, and cognitive science became the hot new interdisciplinary specialty or, more accurately, aggregation of specialties. It was a mind-based science relying on experimental methods by means of which reasonable inferences could be made about mental processes. By the 1980s, cognitive science studies were going on in the psychology departments of nearly every American university, and a handful of universities had created semi-independent institutes of cognitive science. We’ll look at this more closely later in this history.