A Substantial Inheritance

By Daniel Seligman

from National Review, October 10, 1994 As a result of genetic research, human nature is making a comeback.

Hereditarianism is on the march. Nature is clobbering nurture. A steady drip, drip, drip of scientific studies is cumulatively telling us that more and more human traits are genetically influenced. Some of the findings are based on studies of twins and adoptions; others have been generated by research in molecular biology and related hard sciences. The media have shown a particular interest in recent data linking genes to sexual orientation, alcoholism, violent and criminal behavior, and obesity, not to mention cheating on wives. "Infidelity: It may be in our genes," proclaimed the August 15 Time cover. The cover story, by Robert Wright, was based on his new book, The Moral Animal: Evolutionary Psychology and Everyday Life, a work heavily influenced by the science of sociobiology — which has also generated a lot of data linking genes to human behavior.

Some of the nature - nurture news stories also touch on IQ, although you would have difficulty deducing from the coverage that in this area there has been no serious dispute for decades about a powerful genetic effect. The August 9 Boston Globe — which was bracing its readers for The Bell Curve: Intelligence and Class Structure in American Life, by Richard J. Herrnstein and Charles Murray (to be published in October) — had a headline that could have appeared forty years ago: "IQ Fight Renewed; New Book Links Genes, Intelligence."

Curiously unnoticed by the reporters and anchorpersons of America is my own favorite finding of recent years: that political beliefs are strongly influenced by genes. The finding, exhaustively documented in the twin study program at the University of Minnesota, asks you to imagine a continuum of political attitudes. At one end are instinctive conservatives, here conceived as people who tend to respect traditional values and established authority; at the other end are rebellious types generally inclined to kick over the traces. One's place on this continuum is established by responses to a battery of questions gauging attitudes toward conservatism. It turns out that the test scores of identical twins (who are, of course, genetically indistinguishable) correlate far more closely than do the scores of fraternal twins (who have only about half their genes in common), even when the identical twins were reared apart and the fraternal twins were brought up together in the same household.

The media's rendering of the news about genes has been uneven, incomplete (especially in dealing with male - female differences), and maddeningly misleading in major respects. Still, there is no doubt that the literate public has been assimilating a few large truths: that genes play a greater role in human behavior than previously posited; that human beings are somewhat less malleable than had been assumed; that human nature is making something of a comeback.

Onward to Utopia

THE centrality of human nature, a.k.a "instinct," was received wisdom in psychology and anthropology early in this century. It was very much onstage in the world's first serious psychology textbook, William James's Principles of Psychology (1890), a work that drew heavily on Darwinian parallels between human and animal behavior. The Darwinian paradigm remained dominant for many decades.

By mid century, however, this model was pretty much undone in the realm of ideas. It was fighting Marxism and Freudianism, whose alternative visions both featured human behavior shaped by the environment. In addition, the master-race version peddled by the Nazis had made hereditarianism much harder to defend. It was gradually supplanted by a commitment to one or another form of cultural determinism. In Search of Human Nature, by Carl N. Degler of Stanford, traces the rise of this new model to anthropologist Franz Boas, who had been assailing hereditarian ideas as early as 1910 and whose students and disciples increasingly nudged the thinking classes toward a model of human development in which "culture," rather than biology, was supreme. By the 1950s, anthropologist Ashley Montagu was proclaiming that man "has no instincts, because everything he is and has become he has learned, acquired, from his culture." In 1961 the president of the American Sociological Society hailed "the new optimism," identified as a conviction that "anybody can learn anything."

This expansive view of human malleability was exactly what numerous social engineers were eager to hear in the Sixties, and it still lingers in high-minded rhetoric about educational reform. In 1987, when he was the chief executive of Xerox, David Kearns made a speech calling for " a new national agenda" and proposing, incredibly, that "every student — without exception — should master a core curriculum equivalent to college entrance requirements." Possibly owing to his utopian credentials, Kearns later became deputy secretary of education in the Bush Administration.

Adapting to the era of limited malleability has not been easy for the media. First, there has been endless confusion about and misrepresentation of the data. One keeps reading that the evidence points to homosexuality being "immutable, not a personal choice" (Los Angeles Times), or that "sexual or-ientation is innate" (New York Times), or that it is "biologically determined" (Boston Globe). Or, when the subject is data pointing to genetic and biochemical markers for violent behavior, that "biology is destiny" (Time). Or, in news stories about a hereditary basis for obesity, that a particular gene "is the cause of" compulsive eating (St. Louis Post-Dispatch).

The principal difficulty with all these formulations — in some cases, they are hedged or qualified elsewhere in the article I am quoting — is that none of the data now emerging postulates any such determined outcomes. The news is about probabilities, not about "destiny." In every case the data concern genetic effects that "predispose" one in this or that direction and thereby change the odds of particular outcomes. They represent new estimates of the "heritabilities" involved in the trait. The heritability of obesity, for example, is apparently somewhere around 0.40, meaning that 40 per cent of the population's variability in body weight is attributable to genes, leaving 60 per cent for environmental effects. (Obesity is generally defined as 20 per cent or more overweight in relation to height and body type. ) For homosexuality the heritability may be as high as 0.50. Some scholars say it is in about the same zone for alcoholism. (Others are profoundly skeptical of any genetic influence at all in alcoholism.) For political attitudes it is about 0.60, a figure raising the question of whether ideological sperm banks are just over the horizon. For IQ the heritability is even higher, by some measures as high as 0.80.

A second, related problem with the press coverage is its insistent politicization of the data. Over and over again, one sees the media spin doctors gravitating to questions about the political implications of the news: whether it is good or bad for this or that politically correct cause, and, if bad, whether such research should be continued.

This was particularly the case with data suggesting a biological basis for violent crime. The existence of such data has been documented in many different ways. Studies have repeatedly shown identical twins to be more alike than fraternal twins in various measures of criminality. It is clear that several traits associated with violent criminals — muscular physique, low IQ, and impulsiveness — are strongly influenced by genes. Dr. Markku Linnoila of the National Institutes of Health has spent many years building a data base relating deficiencies in serotonin (a brain-based chemical that facilitates transmissions between neurons) to impulsive violent behavior, and almost nobody doubts he is on to something.

The Nazi Tradition?

THE BIG issue about such studies nowadays is not so much their validity as the permissibility of pursuing them at all. The hangup here is racial:

Justice Department data indicate that blacks, who represent about 12 per cent of the U.S. population, commit about half of all violent crimes (defined as murder, non-negligent manslaughter, rape, aggravated assault, and robbery). Which raises the prospect that any research into the genetic and/or biological roots of violent crime would at some point be addressing differences in racial propensities. Numerous scholars are determined that no such research be done, and scholars wishing to do it are endlessly told that they are acting in the Nazi tradition.

Prominent among those making such points is Dr. Peter Breggin, founder of the Center for the Study of Psychiatry, who was recently quoted in the Atlanta Journal and Constitution as concerned that the research would turn into a witch hunt against inner-city black kids. He added: "For America to suggest that the problem lies in them is hypocritical and evil, and to think of doing genetic studies in our inner cities is very close to the Nazi philosophy of blaming and oppressing the victim." Two years ago, the NIH was supporting a conference, to be held at the University of Maryland, on genetic factors in crime. Breggin howled, as did the Congressional Black Caucus. NIH Director Bernadine Healy instantly caved, and the conference was never held.

Political correctness has also been onstage in coverage of the data on gays. In this instance, however, there have been no demands for suppression of the data, which the gay-rights movement generally finds congenial. The new findings here have mainly been identified with two researchers. One is neurobiologist Simon LeVay, who in 1991, when he was at the Salk Institute in La Jolla, reported that a particular cell cluster in the hypothalamus was smaller in gay men than in straight men. The other is Dean Hamer of the National Cancer Institute, who reported in Science last year that he had found differences in the DNA of gay and straight men. Both LeVay and Hamer have repeatedly stated that their research does not point to a "gay gene" and does not imply that homosexuality is determined before birth.

Why, then, would so many media accounts create the opposite impression? Doubtless a contributing factor is the difficulty so many newsrooms have in dealing with complex quantitative data. But I believe that the main reason is political: the concept of a predetermined sexual orientation offered irresistible polemical opportunities to PC editorialists. For openers, it gave them a chance to beat the "Radical Right" over the head. If evangelicals say that homosexuality is "immoral," that must mean they believe gays have a choice in their sexual orientation. So it would be nice to argue that no choice is involved — gayness, no less than straightness, is a God-given trait. As elaborated by a Boston Globe editorialist: "The arguments of homophobes usually imply that homosexuals are somehow making a perverted choice. But the findings of Hamer's team . . . would tend to show that homosexuality . . . is biologically determined. . . . It could ease the struggle to secure equal protection for all Americans, regard less of sexual orientation."

The notion of a biologically determined sexual orientation had another attractive implication for progressive journalists. It meant that parents could no longer rationally defend their objections to gay influences in their children's lives. As Time argued in an article a year ago (July 26, 1993): "Parents might be more relaxed about allowing children to have gay teachers, Boy Scout leaders, and other role models, on the assumption that the child's future is written in his or her genetic makeup." Note, however, that this case crumbles fast as we move from biologically determined outcomes to mere tendencies. If a boy had any predisposition to gayness, his parents would possibly be more concerned about gay Scoutmasters than if they had never heard of the new research.

An amusing footnote to these arguments emerged from some comments made by Dean Hamer at last winter's San Francisco meeting of the American Association for the Advancement of Science. At a news conference, Hamer expressed concern about one possible application of his research. He raised the possibility that the findings would lead eventually to prenatal tests for the predisposition to homosexuality, worried that some parents might elect to abort any fetuses at risk of being gay, and said he hoped to patent the gene in question and prevent homophobic parents from misusing his research. His position was widely reported, and applauded, and my search in Nexis turned up a non-amazing non-event. There were no editorials saying Hamer's plan was in conflict with a woman's right to abort unwanted pregnancies.

'Anything You Can Do . . .'

POLITICAL agendas are also discernible in the media treatment of data on male - female differences. The press has done fairly well at rendering the work of Harvard psychologist Carol Gilligan — Nexis was recently offering 547 articles that mention her — and especially the core concepts of her book In a Different Voice, which portrays women as far more empathetic and "caring" than men. This thought, which had arguably occurred to your grandmother long before Professor Gilligan got around to it, has now been assimilated by most feminist thinkers. But the media and modern feminism are still rigidly rejecting the avalanche of data depicting basic differences in male and female intellectual skills.

A striking instance of the rejection was the colossally uninformed coverage of the lawsuit last winter in which the American Civil Liberties Union and the National Center for Fair & Open Testing called upon the U.S. Department of Education to declare the Scholastic Aptitude Test in violation of Title IX of the Education Amendments of 1972, which bars sex discrimination in federally funded education. The suit's basic proposition: that the SAT (the name has been changed, so that the "A" now stands for Assessment) obviously discriminates against young women. Principal evidence: that women represent 55 per cent of the high-school juniors taking the preliminary SAT but only 40 per cent of those whose test scores qualify them for National Merit Scholarships. To qualify, you have to be above the 98th percentile of the testees.

A thought that was almost impossible to find in media coverage of this event was that this is precisely what serious students of male - female differences would have expected. There is broad (not quite total) agreement that men and women are on average equal in mental ability: they have different strengths and weaknesses, with a huge advantage for men in spatial abilities, which are deeply implicated in mathematical talent, and an offsetting verbal advantage for women. Camilla Benbow of Iowa State University is among the numerous scholars who believe these differences have a biological basis.

If the sexes are on average equal in ability, why would men be dominant among the National Merit Scholarship winners? Because in virtually all mental domains, males are more variable than females, i.e., the distribution of their scores is less bunched around the mean. David Lubinski of Iowa State and Professor Benbow, two prominent researchers who have studied the variability issue, have analyzed the test scores of several hundred thousand high-school students and concluded that even in domains where females have a higher average, males will be more variable. Obvious implication: in any sizable group of gifted (or retarded) students, you would expect males to be overrepresented.

I said above that it was "almost impossible" to find this thought in the media. In fact, I stumbled upon it in only one place: in a publictelevision discussion program called To the Contrary. The program has only female discussants, and on the day I tuned in one of them was Linda Chavez, who said that the National Merit Scholarship results were not surprising, since the greater male variability was well established. To be sure, Miss Chavez is a conservative and an occasional NATIONAL REVIEW contributor.

Taking everything together, the emerging limits-to-malleability perspective looks like better news to conservatives than to liberals. Down through the years, conservatives have almost always been less attracted to political initiatives — public housing, penal rehabilitation, the Job Corps, Head Start, international Communism — that were in some measure advertised as creating new and better kinds of human beings. Conservatives tend to be far gloomier than leftists and liberals in judging the possibilities of changing mankind. In A Conflict of Visions, published in 1987, Thomas Sowell argued persuasively that their different perspectives on human nature were fundamental to their disagreements on a wide range of public-policy questions. Contrasting the utopianism of the Left with the "constrained vision" of the Right, Sowell wrote: "What fundamentally distinguishes the two visions is their respective perceptions of human potential."

In the IQ debate, or at least that portion of it centering on the nature - nurture issue, conservatives have generally seemed quite comfortable with data running up the score for nature, possibly because the evidence confirms their intuitive doubts about so many ameliorative social programs. By the same token, strenuous resistance to the data tends to come from scholars on the Left. Typically they have been Marxists, Stephen Jay Gould of Harvard and Leon Kamin of Northeastern being among the more prominent. The single most hard-line statement against a genetic basis for IQ is still Not in Our Genes, a 1984 work by R. C. Lewontin, Steven Rose, and Leon Kamin, who posit that IQ studies are a weapon employed by the ruling class to hold down the poor and minorities, and who seem unable to discuss the human condition without dragging in Marx, Engels, Feuerbach, and "revolutionary philosophers and practitioners like Mao Tse-tung." Kamin was one of the scholars turned to by the Boston Globe for its recent report on the Herrnstein - Murray book. He was quoted as stating that the book was "politics masquerading as science."

Guaranteed: no shortage of politics as the gene data unfold.

Mr. Seligman, a Fortune columnist, is the author of A Question of Intelligence: The IQ Debate in America (Citadel)


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