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Gene Misbehaving

Robert Plomin

Behavioral Genetics: The Clash of Culture and Biology. Ronald A. Carson and Mark A. Rothstein, eds. 206 pp. Johns Hopkins University Press, 1999. $39.95.

Ever since Shakespeare brought the words "nature" and "nurture" together to describe Caliban's character in The Tempest ("on whose nature nurture cannot stick"), these two words, both so warm and cuddly on their own, have been at the eye of a tornado when juxtaposed with "behavior." As a behavioral geneticist, what I find most remarkable is the rapidly growing acceptance of genetic influence on behavior and behavioral disorders. This is true for the public and even for social scientists who have had a long way to go from the environmentalism (you-are-what-you-learn-ism) that dominated these fields for so many decades. For example, even in the 1980s, autism was thought to be environmentally determined, caused by parents' cold treatment of their infant. Now it is known to be one of the most heritable behavioral disorders in childhood, and specific genes are beginning to be identified.

The debate has shifted from asking whether genetic influence is important to asking about the implications of finding genetic influence and, especially, finding specific genes responsible for the nearly ubiquitous influence of genes on behavior. This book, edited by a professor of medical humanities and a professor of law, is primarily concerned with the evils of genetic determinism, which they believe dominates behavioral genetic research and applications. The authors presumably do not deny that there are thousands of rare single-gene disorders that are deterministic in the sense that they are necessary and sufficient for the development of the disorder. If you inherit the gene for Huntington's disease you will die from Huntington's disease regardless of your other genes or your environment. The editors and many of the authors believe that such genetic determinism has spilled over into the study of behavior.

But such genetic determinism is surely a straw man for geneticists, although perhaps not for humanists and lawyers. I know most of the researchers in this area, and I don't know of a single one who believes in genetic determinism for complex behavioral traits. As Floyd Bloom says in the preface to this book, "Do I think that there is only one gene 'responsible' for alcoholism, or any other complex behavioral disease of emotion, cognition, or social interaction? Certainly not." The current excitement is about finding multiple genes in complex systems in which each gene acts like a probabilistic risk factor rather than a single gene necessary and sufficient for the development of the disorder.

In the middle of these essays on genetic determinism and its political and legal implications are two solid articles providing overviews of behavioral genetic research, one of them rather technical in relation to finding genes for complex traits. Unfortunately, the editors make no attempt to integrate these two behavioral genetic papers. The rest is not really about behavioral genetics but includes some interesting discussions about the use and abuse of genetics in legal settings, such as the possibility that the criminal justice system will go beyond assigning legal responsibility and punishment for crime to prevention of crime through surveillance and preventive detention.—Robert Plomin, Social, Genetic & Developmental Psychiatry Research Centre, Institute of Psychiatry, London

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