The Mind-Brain Problem

An Argument for Mind, by Jerome Kagan, Yale University Press, $27.50

Will the sum and substance of that evanescent phenomenon we call mind one day be completely understood in terms of the physical structure and functioning of the brain? Some philosophers and scientists think so. They believe that even the deepest puzzlements of the human psyche—awareness, the sense of self, and consciousness itself—will yield to the scientific investigations of neuronal circuitry and chemis­try. Thanks to a host of new and ever-improving brain-monitoring and imaging technologies, we will come to see not only how brain architecture and activity correlate with consciousness but how they cause it—and even, if we agree with the philosopher Daniel Dennett, how they are it. If successful, this dazzling feat of reductionism will close the Cartesian mind-body divide and bring the intractable mind fully into the Darwinian paradigm, making the seat of the soul no less a mystery than any other highly evolved product of natural selection.

Or will it? As one might expect, dissenters and doubters abound. Among them, there is possibly no more interesting or qualified a skeptic than psychologist Jerome Kagan, a professor emeritus at Harvard University and the former director of its Mind/Brain/Behavior Interfaculty Initiative. In a career marked by works that have helped define and shape his still relatively young field—Change and Continuity in Infancy, The Nature of the Child, Galen’s Prophecy: Temperament in Human Nature, and Three Seductive Ideas are just a few of his titles—Kagan has been at the forefront of what is called the cognitive revolution in psychology. More to the point, he has been party to a major paradigm shift within his discipline. Simply put (and granting the existence of widely divergent schools within each broad paradigm), that shift has moved the field from an emphasis on nurture to one on nature, from Freudianism and behaviorism at one end to evolutionary psychology and neuroscience at the other.

To be sure, the biological influence on mind and behavior was no more completely absent from the earlier nurturing emphasis than environmental and educative factors are from the current stress upon biology. Freud himself began his career as a neurologist and, by his own admission, would have gone more deeply into the study of the mechanism of the brain had he not felt so constrained by the relatively limited technology of his time. It simply wasn’t possible then to observe and analyze the brain in the ways that it is now. So Freud developed the talking cure, psychoanalysis, exploring the unconscious mind to disclose what he believed to be the most determinative influences in the infant’s earliest sexual experiences. For their part, evolutionary psychologists and other “naturists” do not dismiss the role of experience and environment in the shaping of the individual. (Natural selection, after all, gives the environment the final say on which genetic traits are adaptively superior.) But these scientists propose that there are fairly rigid parameters on the realm of what is possible in our mental lives, parameters shaped at the level of the gene. While sociobiologists argue that even human morality grows out of biology, some neuroscientists cast doubt on the possibility of free will, suggesting that the brain makes up one’s mind before the mind does.

Such aggressive claims at both ends of the nurture-nature spectrum—that we are sophisticated rats responding to environmental stimuli, or that we are merely the elaborate expressions of deeply wired genetic programming—represent the kind of imperial reductivism to which any scientific pursuit is prone. Defenders of that imperial impulse will say that reductionism—reducing complex phenomena to their fundamental elements and workings—is precisely what modern science is about. Quantum theory might have complicated the game a little by showing that the observer’s perspective affects the nature of the phenomenon under investigation. But isn’t science still primarily a reductive enterprise?

Yes, and yet not quite. The hesitation is crucial. The impulse that gives rise to the qualifying demurral may be as important to the human enterprise of science as is its reductive logic. It is the mind’s healthy acknowledgment of the limitations of its own mind-made products. Those who practice science as a form of knowledge arguably benefit from an almost ironic (or is it tragic?) sense of how their science falls short of being a comprehensive form of knowledge. That sense certainly distinguishes Kagan’s work, not least in the book at hand.

Somewhat deceptively titled, this is not an abstract or discursive “argument for mind.” It is an intellectual autobiography, rich with reflections on the author’s 50-some-year involvement with a scientific discipline. What emerges is the portrait of a mind engaged with, but not captive to, a discipline’s assumptions and methods—a mind that was enlivened, directed, but seldom constrained by the scientific effort to understand the mind itself. Explaining why, in 1948, he decided to study psychology and not biochemistry or law, Kagan spoke of “the hope that its discoveries would illuminate the human mind and, as a dividend, suggest ways to alleviate suffering.” What is interesting about those motivations is that they would have found little encouragement in the kind of practical work (“recording the behavior of rats traversing a maze,” Kagan writes) that dominated psychology when he began his studies at Yale University. Yet Kagan was drawn to psychology out of the conviction that it could be—and should be—as engaged with philosophical and moral questions as was The Brothers Karamazov, the Dostoyevskian masterpiece that had so absorbed him at age 13. Kagan’s sense of psychology’s potential and purpose defied the dominant practices of the field even at the outset of his engagement with it.

That gentlemanly defiance has persisted. It began to assert itself while the two dominant models of the nurture paradigm, Freudianism and behaviorism, were starting to lose some of their explanatory authority. Both models shared the throne when Kagan did his undergraduate and graduate work at Yale, though the Pavlovian focus on the conditioned reflex sat a little higher than the Freudian concern with neuroses and other psychopathologies resulting from the inadequately examined unconscious. However different the models were, both subscribed to what Kagan calls “the catechism that change and variation in thought and behavior were due primarily to experience.” He elaborates on what this catechism stressed and scanted:

Although there was tacit acceptance of the assumption that the products of experience were instantiated somewhere in the nervous system, the impossibility of measuring the brain made it easy to ignore its contribution. This perspective married Locke’s insistence on the power of sensory events to Darwin’s emphasis on adaptations but for the moment was indifferent to biology because European immigration to the United States had made arguments for a biological contribution to human variation politically incorrect.

Kagan’s temperamental skepticism was helped along by that of his mentor, Frank Beach, who introduced him to inconvenient facts that were gradually bringing down the “beautiful palace of behaviorism.” One such fact was John Garcia’s demonstration that it was impossible, as Kagan explains, to “teach any response to any animal because each animal had biological preferences that, in some cases, could not be abrogated.” A rigorous program of conditioning might succeed in getting a pig to pick up an object and drop it into a bucket, but eventually the pig-headed creature returns to his usual ways and buries the object in the dirt. In some behaviors at least, instinct eventually will out.

If Kagan learned a valuable lesson about the dangers of putting inordinate faith in any scientific theory, he acknowledges that he did so not only at others’ expense. At the time he departed from Yale to take a position at Ohio State, he was, in his words, “irrationally opposed to awarding biology any significant influence on development and was convinced that the behaviors, beliefs, and emotions established early in life would persist unless there were consistent attempts to change them.” None of those intellectual assumptions survived the theoretical upheaval in which he was soon to take part, the cognitive revolution that would confer upon innate mental rules a power that was at least equal to that of experience.

Kagan did hold on to one of his early ideas (though even it would undergo modifications): the idea that differences in mood, behavior, and beliefs among individuals were, above all, the result of private, symbolic reconstructions of childhood experiences—not so much the experiences themselves, but the shape or meaning given to them. One of his first research projects focused on children’s constructions of the concepts of “male” and “female” to explore how they came to be associated with other ideas—for example, why children saw a saw-toothed object as male and a curved design as female. Were these associations conditioned, and if so, how? The pursuit of answers to those questions drew Kagan toward a growing awareness of the power of culture to shape the meaning of words, even as it sensitized him to the highly individual and emotional charge that words can carry. This multivalency of the word made the young psychologist increasingly wary of such tools as personality tests, which tend to assume that one person’s sense of a word like sad carries the same freight that it does for someone else.

Unquestionably, the biggest step in Kagan’s theoretical odyssey took place in 1957 when he became involved in evaluating the results of a longitudinal study of “typical American children” from several hundred families—mostly white and middle class—living within 40 miles of Yellow Springs, Ohio. Launched in 1929 and sponsored by the Fels Research Institute at Antioch College, the study gave Kagan the chance to explore the four core assumptions that governed child psychology in America from the 19th century well into the late 1970s.

The first swore allegiance to the significance of experience, especially maternal love and effective socialization of good character. The second held that habits, values, and emotions established early would be preserved indefinitely. The third alleged that psychological growth was gradual, and the last declared that “freedom from coercion” was the ideal state every child should attain.

On the basis of such assumptions, idealistic psychologists in the 1950s believed that if they could identify parental behaviors that accounted for differences in the levels of aggression, conformity, obedience, and academic performance in their offspring, they could tell parents what to do to produce happier, more successful adults.

While such assumptions and such a mission might seem nothing more than general good sense married to idealism, Kagan’s evaluation of the study’s data and subjects began to expose the chinks in the edifice of developmental theory—and to show how, in certain respects, some assumptions led to a rigid and specious fatalism. The idea that the earliest years of infancy were the most determinative, for example, took a strong hit. Finding that behavioral differences in an infant’s first three years had little bearing on their psychological differences as adults, Kagan discovered that behavior exhibited in the years between six and 10, after a child entered school, was a fairly good predictor of adult behavior. But there was one exception to his findings about the minimal effect of the earliest years: infants who had been described as “passive to challenges” tended to become uncertain, insecure, and needy adults. In their book Birth to Maturity, Kagan and his colleague Howard Moss observed that this trait might have “a constitutional component, meaning a temperamental bias.” Kagan had no idea that he would return to this subject 40 years later and that it would prove to be the focus of some of his most enduring work—work that would demonstrate the power of temperament to shape personality and behavior but that would resist the fatalistic conclusion that this biologically rooted tendency had the final say in determining the psychological well-being of the adult.

The intervening years would be busy ones, but rather than tell the step-by-step story of his successive research projects and books, Kagan relates how his developing work led him to think about certain enduring psychological problems and mysteries. Why, for example, are certain psychotherapeutic regimes seemingly more effective at one time than another, and, in particular, why does their curative power decrease the more the therapist’s secrets become common knowledge? Kagan’s answer: “Humans have the unfortunate habit of mistaking originality for wisdom because novelty is alerting and, if understandable, creates an intuition of truth.” The fate of Freudian psychoanalysis—declining efficacy due to increasing banality—is one that Kagan fears may befall other newer therapies, including cognitive behavioral therapy.

Most interesting, though, in relation to the book’s broader “argument for mind” are Kagan’s reflections on the uniqueness of hu­man consciousness and the unlikelihood of re­ducing it to even the most minute descriptions of brain activity. Kagan came to his convictions on these matters not by ignoring or denying the enormous strides that the neurosciences have made during the last half-­century. He refers to a lecture delivered more than 50 years ago by Francis Crick shortly after he and James Watson announced the structure of DNA, one paragraph of which suggested that future research would reveal the power of neurochemistry in shaping human behavior. “I wrote in the margin of that page, ‘No!’” Kagan writes. “Stubborn facts have forced me, kicking and screaming, to relinquish the pleasing premise of biology’s irrelevance that attracted me to psychology so many years ago.”

But a growing appreciation of biology (not least in his own work on temperament) did not force him to relinquish his resistance to absolute reducibility, which he maintains on several points. He points out, for one, that neuroscientists exploring the neural correlates of consciousness too often seem to think that consciousness is one state. It may be better, Kagan argues, to think of many possibly related states, such as sensory awareness, cognitive awareness (mental activity that occurs without sensory stimulus), awareness of the ability to choose a behavior or to control actions or emotions (free will), and awareness of one’s own personal properties.

Persuasively, Kagan argues for the principle that the whole is more than the sum of its parts, a view that “regards every observed event as an emergent form that depends on, but is not identical with, its elementary foundations.” In relation to psychological phenomena, he explains, “this perspective implies that the meanings of words that refer to perception, feeling, belief, intention, and habit will differ from those describing the biological events that permit those functions to be actualized.” Unfortunately, in Kagan’s view the great advances in brain-monitoring technology over the past 50 years have not been accompanied by greater caution about what the resulting pictures of assorted brain-states mean. And that shortcoming, he insists, has much to do with sloppy terminology.

Neuroscientists and psychologists often use the same words for a psychological process (for example, “fear,” “consciousness,” “arousal”), but the meanings differ because the referents for the neuroscientist are brain circuits, whereas they are reports of feelings and observed behaviors for the psychologist. Stated differently, the meaning networks for words that name psychological events are distinct from those that name brain activity.

Kagan is not simply quibbling about semantics. He is arguing, more importantly, that the most detailed brain profile will not define, will not be the same thing as, a psychological state but at best have “a certain probability” of accompanying that state. The mental phenomenon eludes the grasp of the most refined measurement of the underlying brain activity. For that reason, Kagan doubts the prediction that it will one day be possible to identify a particular brain state that precedes a seemingly freely willed action—say, for instance, the decision to take salad rather than soup from a cafeteria offering. “I suggest that this hope cannot, in principle, be realized,” he writes, “because there cannot be a single brain state across all individuals that precedes the choice of salad over soup.” To Kagan, the power of both culture and individual temperament in shaping the symbolic representations of our experiences suggests the infinite variety of mental life, any two or more instances of which may share identical underlying neurochemical states yet be, each in its own qualitative way, as different from one another as night and day.

Kagan understands very well the scientific desire for certainty. He admires it and what it has produced. But in the quest to understand the mind, Kagan insists that a humble recognition of what is most important about this complex phenomenon—its capacity to impose symbolic interpretations upon experiences, interpretations that include emotional, moral, aesthetic, and other dimensions—is made possible but not explained by that marvelous coil of living circuitry that constitutes the brain. Humility should in no way discourage or denigrate the study of the mechanism of the brain. It should only make practicing neuroscientists—and, for that matter, all who practice and admire science—more keenly aware that the techniques, theories, and terminology of a particular scientific pursuit may have only limited power in comprehending the complex phenomena of nature, including human beings and their minds. The discourses of different sciences may overlap and illuminate aspects of one another, but there is no compelling proof, despite some eloquent claims to the contrary, that all are reducible to the terms of one master science, whether biology or physics. A reasonable appreciation of the limits of what the different sciences can explain about a phenomenon like the mind might be an immeasurable boon to the pursuit of science in general. If so, it is an appreciation to which Kagan has greatly contributed.