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Are We Hardwired? : The Role of Genes in Human Behavior
by William R. Clark and Michael Grunstein

Reviewed by
Beryl Lieff Benderly

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The short answer is No. As biologists Clark and Grunstein show in their brisk and often enlightening review of what biology knows about the relationship between genes and the biological systems involved in behavior, the things that people do hardly ever arise directly from the promptings of their DNA. But if we humans do not possess pre-soldered circuits that determine our daily actions, we nonetheless each have neurological "wiring" whose characteristics strongly influence those actions. And genes clearly play a central role in both how that system comes into being and how it works.

The relative contribution of physiology and experience to human behavior has, of course, been argued by generations of scientists of every persuasion. Unlike many authors, Clark and Grunstein venture onto this hotly contested terrain not to stake out a particular ideological position but to offer a road map of the relationship between genetic differences among individuals of many species and the biological variations that may directly or indirectly affect how they behave. Starting with the paramecium and continuing up to ourselves, the authors provide an informative and readable survey of what genes are, what they do, how scientists find them, what roles they play in a variety of cellular functions, and how those functions appear to affect the workings of larger systems in more advanced organisms, most particularly the human nervous system. Even more impressively, the authors accomplish all this without losing the general reader in reams of jargon or obviously taking sides in the nature-nurture dispute.

Interesting though the effects of particular genes on protists' ion channels may be, however—and in Clark and Grunstein's hands they are quite interesting indeed—the larger debate concerns not paramecia but ourselves, not how cells work but what determines individual human destinies. That inheritance plays a significant role in people's talents and propensities is beyond dispute, and the book discusses at length the relationship between genes and various parts of the human nervous system, the obvious biological substrate of human behavior. As far as this discussion goes, the authors present a most useful overview.

But given the question that they pose in their title, it does not go nearly far enough. Though they handle biological issues with assurance and sophistication, their approach to non-biological ones—which, they admit, also have a major impact—is stunningly less sure. Remarkably, only very late in a 272-page discussion of the sources of such behaviors as substance abuse, reasoning and choosing a mate do they devote a total of two perfunctory paragraphs to language and culture, which have played crucial parts in our species' adaptation for many millennia. This oversight reveals at best the authors' unfamiliarity with vast, relevant literature and at worst an unadmitted bias that casts doubt on many of their other comments. For nearly the entire book they lump all the non-genetic factors affecting human behavior—which include, in addition to symbolic communication and cultural values, such basic influences as family and childrearing patterns, social structure, technology, and much else—under the single rubric of "environment," which in fact they never adequately define.

Human beings, however, do not live only or even mostly in the world of objective external forces, but rather within the symbolic and psychological universe that each individual constructs over a lifetime out of his or her own experience in specific cultural and personal contexts. "Some have argued that culture now has a life of its own, even that it evolves independently of our genes, and controls human behavior in ways that simply do not apply to animals," Clark and Grunstein state, apparently—and astonishingly—dismissing the findings of history, linguistics, physical anthropology, archeology, psychology, and all the social sciences as the mere "arguments" of "some." Nonetheless, this claim "may well be true," they acknowledge, seemingly unaware of some of the most crucial elements undergirding homo sapiens' spectacular adaptive success.

Giving such short shrift to factors so obvious and important constitutes a major disappointment in an often quite useful book. Still, for readers content to use it as a review of genetics rather than an investigation of the sources of human behavior, Are We Hardwired? provides a sensible and understandable introduction to the relevant biology.

Beryl Lieff Benderly's books include The Growth of the Mind (with Stanley I. Greenspan, M.D.).

Clark, William R. & Grunstein, Michael. Are We Hardwired? : The Role of Genes in Human Behavior. Oxford University Press, New York, NY, 2000.

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