he academic world is bracing for an intellectual firefight this fall,
with the publication of a book claiming that intelligence is largely
inherited and cannot be changed significantly by external influences.
The authors, Harvard psychologist Richard J. Herrnstein and conservative political analyst Charles Murray, say this idea is the key to understanding America's social problems. They claim a direct correlation between IQ and income, social status, crime, welfare dependency and illegitimacy.
"The Bell Curve: Intelligence and Class Structure in American Life" (Free Press), due out next month, is expected to reignite the longstanding "nature vs. nurture" debate - the question of which human traits are innate and which are shaped more by life experience. On a political level, it also promises to inflame old tensions among scholars on issues ranging from race to egalitarianism.
The premise of "The Bell Curve" raises several provocative questions simmering beneath the surface of social science and politics. Are there inexorable differences in intelligence not only among individuals, but also among racial and ethnic groups? Are certain individuals born with low intelligence predisposed to a life of crime? Should the smartest couples somehow be encouraged to procreate? Should government programs aimed at improving mental capability, such as Head Start, be scrapped?
Even before it hits the bookstores, "The Bell Curve" is being criticized as inaccurate and inflammatory. "It's politics masquerading as science," said Leon Kamin, professor of psychology at Northeastern University.
For the most part, "The Bell Curve" emphasizes differences in intelligence among individuals, and not the intelligence levels of racial or ethnic groups as a whole.
But since the authors accept IQ tests as unbiased and reasonable measures of intelligence, and blacks as a group have historically scored 10 to 15 points lower than whites on such tests, the Murray-Herrnstein thesis inevitably suggests that blacks, as a group, are on average less intelligent than whites.
Even those scholars who do not dismiss the book acknowledge it will be greeted like a party guest who insists on bringing up forbidden topics.
"There's a long memory of acts of retaliation in academia on this. Everyone recalls the calumny that was heaped on Arthur Jensen's head 20 years ago," said James Q. Wilson, a professor at the University of California at Los Angeles, referring to the Berkeley scholar who was branded a racist after articles in 1969 and 1972 linking intelligence and genes.
"But that memory is slowly being offset by the growing weight of evidence about this," said Wilson, a public policy analyst who collaborated with Herrnstein on "Crime and Human Nature" in 1985. "People are more prepared to say these things and more prepared to hear about these things."
The anticipation building for "The Bell Curve" - named for the shape of the graph showing the distribution of a population's IQ scores - is compounded by a dramatic twist: Herrnstein, 64, is gravely ill with cancer. Some friends wonder whether he will live to see his ultimate work unveiled.
Herrnstein, who lives in Belmont, has been a controversial fixture in the Harvard psychology department for decades. In 1971, he was harshly criticized for an Atlantic Monthly article where he first suggested a link between genes and intelligence. Many balked at the implication that some racial groups, on average, were born more intelligent than others.
Murray, a fellow at the American Enterprise Institute, is well known in conservative circles for his warnings about a growing "underclass," and for wanting to abolish welfare and put "neglected" children into orphanages. He is skeptical, on the whole, of the effectiveness of government interventions, such as job training for welfare recipients.
Using primarily existing studies, including experiments done with identifical twins separated at birth, Herrnstein and Murray conclude that intelligence is largely inherited and cannot by improved significantly after birth. They accept the validity of IQ tests as a measure of intelligence - itself a hugely controversial notion.
Herrnstein, in an interview this spring, said the book goes on to establish a link between intelligence and a whole range of societal behavior - economic success, criminal activity, welfare dependency and educational performance, for example.
"If you accept the correlation between crime and IQ, then some people are genetically predisposed to break the law. People on welfare on average have low IQs. The income distribution in this country is an echo of IQ distribution," Herrnstein said.
"What we are struck by is, the genetic distribution of intelligence is taking a huge toll on how our society functions. We want people to recognize that," he said. "My hope is that we will . . . put things on the table, so that people will be able to filter it into their thinking about public policy."
In part because of the racial dimension, and in part because there are sharply divided camps on the question of whether intelligence is truly genetically transmitted, the Herrnstein-Murray thesis is expected to deepen rifts between scholars.
The evolution of the nature vs. nurture debate on intelligence is a rancorous one. While most psychologists scoffed at Jensen and Herrnstein some 20 years ago, a 1988 survey of experts in the field showed that most agreed that intelligence may well be largely heritable.
What Herrnstein first touted two decades ago "is standard doctrine now," said Ellis Page, professor of education at Duke University. "The more you look at the journals, the more amazing the role of genetics seems to be."
Most experts in genetics, however, say there is no hard DNA evidence that certain traits - intelligence, alcoholism, mental illness, even homosexuality - are genetically transmitted.
"I don't think we're at a point where we can draw a strong conclusion," said Jonathan Beckwith, a geneticist at Harvard Medical School. Because no scientist has identified a set of "intelligence genes," scholars must rely on studies involving separated identical or fraternal twins, whose reliability is disputed, he said.
Even among those who agree that intelligence is inherited, there is considerable doubt about the Herrnstein-Murray thesis that little can be done to improve inborn mental ability. Though twin studies seem to show that intelligence is "primarily genetic in origin," said Tom Bouchard, a psychologist at the Minnesota Center for Twin and Adoption Research, "clearly intelligence can be impacted by environment."
"Genetics does not suggest something is unalterable," said Evan Balaban, former associate professor of organismic and evolutionary biology at Harvard, and now a senior research fellow at the The Neurosciences Institute in La Jolla, Calif.
Many scientists hypothesize that intelligence is shaped by a mixture of genes and environmental influences. Like Beckwith, Balaban expressed some impatience with social scientists making more comprehensive assertions about the role of genes. "All this talk of biological determination is being driven by the people who have the least training in genetics."
Yet adherents to the Herrnstein-Murray view are legion, and they are fiercely loyal. Many hope "The Bell Curve" will reopen academic discussions long viewed as taboo.
"The media downplays heritability and overplays bias in IQ testing, but most of the experts hold the opposite views," said David Row, a professor of family studies at the University of Arizona at Tucson and author of "The Limits of Family Influence: Genes, Experience and Behavior."
"If you take someone off the street and try to make them a professional baseball player, no amount of training or batting practice is going to make them one," he said. "More nurture doesn't make a shy person sociable, or make someone aggressive less so."
"People are actively looking for genes that influence a variety of behavior. It's the early part of the search and we don't have the answer yet," Row said. "But a lot of the evidence is already there."