There are, of course, many arguments against such a genetic explanation. Many studies have shown that the disadvantaged environment of some blacks has depressed their test scores. In one study, in black families in rural Georgia, the elder sibling typically had a lower I.Q. than the younger. The larger the age difference is between the siblings, the larger is the difference in I.Q. The implication is that something in the rural Georgia environment was depressing the scores of black children as they grew older. In neither the white families of Georgia, nor white or black families in Berkeley, California, were there comparable signs of a depressive effect of the environment.

Another approach is to say that tests are artifacts of a culture, and a culture may not diffuse equally into every household and community. In a heterogeneous society, subcultures vary in ways that inevitably affect scores on I.Q. tests. Fewer books in the home mean less exposure to the material that a vocabulary subtest measures; the varying ways of socializing children may influence whether a child acquires the skills, or a desire for the skills, that tests test; the “common knowledge” that tests supposedly draw on may not be common in certain households and neighborhoods.

So far, this sounds like a standard argument about cultural bias, and yet it accepts the generalizations that we discussed earlier about internal evidence of bias. The supporters of this argument are not claiming that less exposure to books means that blacks score lower on vocabulary questions but do as well as whites on culture-free items. Rather, the effects of culture are more diffuse.

Furthermore, strong correlations between home or community life and I.Q. scores are readily found. In a study of 180 Latino and 180 non-Latino white elementary school children in Riverside, California, the researcher examined eight sociocultural variables: (1) mother’s participation in formal organizations, (2) living in a segregated neighborhood, (3) home language level, (4) socioeconomic status based on occupation and education of head of household, (5) urbanization, (6) mother’s achievement values, (7) home ownership, and (8) intact biological family. She then showed that once these sociocultural variables were taken into account, the remaining group and I.Q. differences among the children fell to near zero.

The problem with this procedure lies in determining what, in fact, these eight variables control for: cultural diffusion, or genetic sources of variation in intelligence as ordinarily understood? By so drastically extending the usual match for socioeconomic status, the possibility is that such studies demonstrate only that parents matched on I.Q. will produce children with similar I.Q.s—not a startling finding. Also, the data used for such studies continue to show the distinctive racial patterns in the subtests. Why should cultural diffusion manifest itself by differences in backward and forward digit span or in completely nonverbal items? If the role of European white cultural diffusion is so important in affecting black I.Q. scores, why is it so unimportant in affecting Asian I.Q. scores?

There are other arguments related to cultural bias. In the American context, Wade Boykin is one of the most prominent academic advocates of a distinctive black culture, arguing that nine interrelated dimensions put blacks at odds with the prevailing Eurocentric model. Among them are spirituality (blacks approach life as “essentially vitalistic rather than mechanistic, with the conviction that nonmaterial forces influence people’s everyday lives”); a belief in the harmony between humankind and nature; an emphasis on the importance of movement, rhythm, music and dance, “which are taken as central to psychological health”; personal styles that he characterizes as “verve” (high levels of stimulation and energy) and “affect” (emphasis on emotions and expressiveness); and “social time perspective,” which he defines as “an orientation in which time is treated as passing through a social space rather than a material one.” Such analyses purport to explain how large black-white differences in test scores could coexist with equal predictive validity of the test for such things as academic and job performance and yet still not be based on differences in “intelligence,” broadly defined, let alone genetic differences.

John Ogbu, a Berkeley anthropologist, has proposed a more specific version of this argument. He suggests that we look at the history of various minority groups to understand the sources of differing levels of intellectual attainment in America. He distinguishes three types of minorities: “autonomous minorities” such as the Amish, Jews and Mormons, who, while they may be victims of discrimination, are still within the cultural mainstream; “immigrant minorities,” such as the Chinese, Filipinos, Japanese and Koreans within the United States, who moved voluntarily to their new societies and, while they may begin in menial jobs, compare themselves favorably with their peers back in the home country; and, finally, “castelike minorities,” such as black Americans, who were involuntary immigrants or otherwise are consigned from birth to a distinctively lower place on the social ladder. Ogbu argues that the differences in test scores are an outcome of this historical distinction, pointing to a number of castes around the world—the untouchables in India, the Buraku in Japan and Oriental Jews in Israel—that have exhibited comparable problems in educational achievement despite being of the same racial group as the majority.

Indirect support for the proposition that the observed black-white difference could be the result of environmental factors is provided by the worldwide phenomenon of rising test scores. We call it “the Flynn effect” because of psychologist James Flynn’s pivotal role in focusing attention on it, but the phenomenon itself was identified in the 1930s when testers began to notice that I.Q. scores often rose with every successive year after a test was first standardized. For example, when the Stanford-Binet I.Q. was restandardized in the mid-1930s, it was observed that individuals earned lower I.Q.s on the new tests than they got on the Stanford-Binet that had been standardized in the mid-1910s; in other words, getting a score of 100 (the population average) was harder to do on the later test. This meant that the average person could answer more items on the old test than on the new test. Most of the change has been concentrated in the nonverbal portions of the tests.

The tendency for I.Q. scores to drift upward as a function of years since standardization has now been substantiated in many countries and on many I.Q. tests besides the Stanford-Binet. In some countries, the upward drift since World War II has been as much as a point per year for some spans of years. The national averages have in fact changed by amounts that are comparable to the fifteen or so I.Q. points separating whites and blacks in America. To put it another way, on the average, whites today may differ in I.Q. from whites, say, two generations ago as much as whites today differ from blacks today. Given their size and speed, the shifts in time necessarily have been due more to changes in the environment than to changes in the genes. The question then arises: Couldn’t the mean of blacks move fifteen points as well through environmental changes? There seems no reason why not—but also no reason to believe that white and Asian means can be made to stand still while the Flynn effect works its magic.

V.

As of 1994, then, we can say nothing for certain about the relative roles that genetics and environment play in the formation of the black-white difference in I.Q. All the evidence remains indirect. The heritability of individual differences in I.Q. does not necessarily mean that ethnic differences are also heritable. But those who think that ethnic differences are readily explained by environmental differences haven’t been tough-minded enough about their own argument. At this complex intersection of complex factors, the easy answers are unsatisfactory ones.

Given the weight of the many circumstantial patterns, it seems improbable to us—though possible—that genes have no role whatsoever. What might the mix of genetic and environmental influences be? We are resolutely agnostic on that.

Here is what we hope will be our contribution to the discussion. We put it in italics; if we could, we would put it in neon lights: The answer doesn’t much matter. Whether the black-white difference in test scores is produced by genes or the environment has no bearing on any of the reasons why the black-white difference is worth worrying about. If tomorrow we knew beyond a shadow of a doubt what role, if any, were played by genes, the news would be neither good if ethnic differences were predominantly environmental, nor awful if they were predominantly genetic.

The first reason for this assertion is that what matters is not whether differences are environmental or genetic, but how hard they are to change. Many people have a fuzzy impression that if cognitive ability has been depressed by a disadvantaged environment, it is easily remedied. Give the small child a more stimulating environment, give the older child a better education, it is thought, and the environmental deficit can be made up. This impression is wrong. The environment unquestionably has an impact on cognitive ability, but a record of interventions going back more than fifty years has demonstrated how difficult it is to manipulate the environment so that cognitive functioning is improved. The billions of dollars spent annually on compensatory education under Title I of the Elementary and Secondary Education Act have had such a dismal evaluation record that improving general cognitive functioning is no longer even a goal. Preschool education fares little better. Despite extravagant claims that periodically get their fifteen minutes of fame, preschool education, including not just ordinary Head Start but much more intensive programs such as Perry Preschool, raises I.Q. scores by a few points on the exit test, and even those small gains quickly fade. Preschool programs may be good for children in other ways, but they do not have important effects on intelligence. If larger effects are possible, it is only through truly heroic efforts, putting children into full-time, year-round, highly enriched day care from within a few months of birth and keeping them there for the first five years of life—and even those effects, claimed by the Milwaukee Program and the Abecedarian Project, are subject to widespread skepticism among scholars.

In short: if it were proved tomorrow that ethnic differences in test scores were entirely environmental, there would be no reason to celebrate. That knowledge would not suggest a single educational, preschool, day care or prenatal program that is not already being tried, and would give no reason to believe that tomorrow’s effects from such programs will be any more encouraging than those observed to date. Radically improved knowledge about child development and intelligence is required, not just better implementation of what is already known. No breakthroughs are in sight.

The second reason that the concern about genes is overblown is the mistaken idea that genes mean there is nothing to be done. On the contrary, the distributions of genetic traits in a population can change over time, because people who die are not replaced one-for-one by babies with matched dna. Just because there might be a genetic difference among groups in this generation does not mean that it cannot shrink. Nor, for that matter, does genetic equality in this generation mean that genetic differences might not arise within a matter of decades. It depends on which women in which group have how many babies at what ages. More broadly, genetic causes do not leave us helpless. Myops see fine with glasses and many bald men look as if they have hair, however closely myopia and baldness are tied to genes. Check out visual aids and gimmicks on any Macintosh computer to see how technology can compensate for innumeracy and illiteracy.

Now comes the third reason that the concern about genes needs rethinking. It is to us the most compelling: there is no rational reason why any encounter between individuals should be affected in any way by the knowledge that a group difference is genetic instead of environmental. Suppose that the news tomorrow morning is that the black-white difference in cognitive test scores is rooted in genetic differences. Suppose further that tomorrow afternoon, you—let us say you are white—encounter a random African American. Try to think of any way in which anything has changed that should affect your evaluation of or response to that individual and you will soon arrive at a truth that ought to be assimilated by everyone: nothing has changed. That an individual is a member of a group with a certain genetically based mean and distribution in any characteristic, whether it be height, intelligence, predisposition to schizophrenia or eye color has no effect on that reality of that individual. A five-foot man with six-foot parents is still five feet tall, no matter how much height is determined by genes. An African American with an I.Q. of 130 still has an I.Q. of 130, no matter what the black mean may be or to what extent I.Q. is determined by genes. Maybe for some whites, behavior toward black individuals would change if it were known that certain ethnic differences were genetic—but not for any good reason.

We have been too idealistic, one may respond. In the real world, people treat individuals according to their membership in a group. Consider the young black male trying to catch a taxi. It makes no difference how honest he is; many taxi drivers will refuse to pick him up because young black males disproportionately account for taxi robberies. Similarly, some people fear that talking about group differences in I.Q. will encourage employers to use ethnicity as an inexpensive screen if they can get away with it, not bothering to consider black candidates.

These are authentic problems that need to be dealt with. But it puzzles us to hear them raised as a response to the question, “What difference does it make if genes are involved?” Two separate issues are being conflated: the reality of a difference versus its source. An employer has no more incentive to discriminate by ethnicity if he knows that a difference in ability is genetic than if he knows it is “only” environmental. To return to an earlier point, the key issue is how intractable the difference is. By the time someone is applying for a job, his cognitive functioning can be tweaked only at the margins, if at all, regardless of the original comparative roles of genes and environment in producing that level of cognitive functioning. The existence of a group difference may make a difference in the behavior of individuals toward other individuals, with implications that may well spill over into policy, but the source of the difference is irrelevant to the behavior.

VI.

In The Bell Curve, we make all of the above points, document them fully and are prepared to defend them against all comers. We argue that the best and indeed only answer to the problem of group differences is an energetic and uncompromising recommitment to individualism. To judge someone except on his or her own merits was historically thought to be un-American, and we urge that it become so again.

But as we worked on the discussion in the book, we also became aware that ratiocination is not a sufficient response. Many people instinctively believe that genetically caused group differences in intelligence must be psychologically destructive in a way that environmentally caused differences are not. In a way, our informal survey of elites during the writing of the book confirmed this. No matter what we said, we found that people walked away muttering that it does make a difference if genes are involved. But we nonetheless are not persuaded. It seems to us that, on the contrary, human beings have it in them to live comfortably with all kinds of differences, group and individual alike.

We did not put those thoughts into the book. Early on, we decided that the passages on ethnic differences in intelligence had to be inflexibly pinned to data. Speculations were out, and even provocative turns of phrase had to be guarded against. The thoughts we are about to express are decidedly speculative, and hence did not become part of our book. But if you will treat them accordingly, we think they form the basis of a conversation worth beginning, and we will open it here.

As one looks around the world at the huge variety of ethnic groups that have high opinions of themselves, for example, one is struck by how easy it is for each of these clans, as we will call them, to conclude that it has the best combination of genes and culture in the world. In each clan’s eyes, its members are blessed to have been born who they are—Arab, Chinese, Jew, Welsh, Russian, Spanish, Zulu, Scots, Hungarian. The list could go on indefinitely, breaking into ever smaller groups (highland Scots, Glaswegians, Scotch-Irish). The members of each clan do not necessarily think their people have gotten the best break regarding their political or economic place in the world, but they do not doubt the intrinsic, unique merits of their particular clan.

How does this clannish self-esteem come about? Any one dimension, including intelligence, clearly plays only a small part. The self-esteem is based on a mix of qualities. These packages of qualities are incomparable across clans. The mixes are too complex, the metrics are too different, the qualities are too numerous to lend themselves to a weighting scheme that everyone could agree upon. The Irish have a way with words; the Irish also give high marks to having a way with words in the pantheon of human abilities. The Russians see themselves as soulful; they give high marks to soulfulness. The Scotch-Irish who moved to America tended to be cantankerous, restless and violent. Well, say the American Scotch-Irish proudly, these qualities made for terrific pioneers.

We offer this hypothesis: Clans tend to order the world, putting themselves on top, not because each clan has an inflated idea of its own virtues, but because each is using a weighting algorithm that genuinely works out that way. One of us had a conversation with a Thai many years ago about the Thai attitude toward Americans. Americans have technology and capabilities that the Thais do not have, he said, just as the elephant is stronger than a human. “But,” he said with a shrug, “who wants to be an elephant?” We do not consider his view quaint. There is an internally consistent logic that legitimately might lead a Thai to conclude that being born Thai gives one a better chance of becoming a complete human being than being born American. He may not be right, but he is not necessarily wrong.

If these observations have merit, why is it that one human clan occasionally develops a deep-seated sense of ethnic inferiority vis-a-vis another clan? History suggests that the reasons tend to be independent of any particular qualities of the two groups, but instead are commonly rooted in historical confrontations. When one clan has been physically subjugated by another, the psychological reactions are complex and long-lasting. The academic literature on political development is filled with studies of the reactions of colonized peoples that prove this case. These self-denigrating reactions are not limited to the common people; if anything, they are most profound among the local elites. Consider, for example, the deeply ambivalent attitudes of Indian elites toward the British. The Indian cultural heritage is glittering, but that heritage was not enough to protect Indian elites from the psychological ravages of being subjugated.

Applying these observations to the American case and to relations between blacks and whites suggests a new way of conceptualizing the familiar “legacy of slavery” arguments. It is not just that slavery surely had lasting effects on black culture, nor even that slavery had a broad negative effect on black self-confidence and self-esteem, but more specifically that the experience of slavery perverted and stunted the evolution of the ethnocentric algorithm that American blacks would have developed in the normal course of events. Whites did everything in their power to explain away or belittle every sign of talent, virtue or superiority among blacks. They had to—if the slaves were superior in qualities that whites themselves valued, where was the moral justification for keeping them enslaved? And so everything that African Americans did well had to be cast in terms that belittled the quality in question. Even to try to document this point leaves one open to charges of condescension, so successfully did whites manage to coopt the value judgments. Most obviously, it is impossible to speak straightforwardly about the dominance of many black athletes without being subject to accusations that one is being backhandedly anti-black.

The nervous concern about racial inferiority in the United States is best seen as a variation on the colonial experience. It is in the process of diminishing as African Americans define for themselves that mix of qualities that makes the American black clan unique and (appropriately in the eyes of the clan) superior. It emerges in fiction by black authors and in a growing body of work by black scholars. It is also happening in the streets. The process is not only normal and healthy; it is essential.

In making these points, there are several things we are not saying that need to be spelled out. We are not giving up on the melting pot. Italians all over America who live in neighborhoods without a single other Italian, and who may technically have more non-Italian than Italian blood, continue to take pride in their Italian heritage in the ways we have described. The same may be said of other ethnic clans. For that matter, we could as easily have used the examples of Texans and Minnesotans as of Thais and Scotch-Irish in describing the ways in which people naturally take pride in their group. Americans often see themselves as members of several clans at the same time—and think of themselves as 100 percent American as well. It is one of America’s most glorious qualities.

We are also not trying to tell African Americans or anyone else what qualities should be weighted in their algorithm. Our point is precisely the opposite: no one needs to tell any clan how to come up with a way of seeing itself that is satisfactory; it is one of those things that human communities know how to do quite well when left alone to do it. Still less are we saying that the children from any clan should not, say, study calculus because studying calculus is not part of the clan’s heritage. Individuals strike out on their own, making their way in the Great World according to what they bring to their endeavors as individuals—and can still take comfort and pride in their group affiliations. Of course there are complications and tensions in this process. The tighter the clan, the more likely it is to look suspiciously on their children who depart for the Great World—and yet also, the more proudly it is likely to boast of their successes once they have made it, and the more likely that the children will one day restore some of their ties with the clan they left behind. This is one of the classic American dramas.

We are not preaching multiculturalism. Our point is not that everything is relative and the accomplishments of each culture and ethnic group are just as good as those of every other culture and ethnic group. Instead, we are saying a good word for a certain kind of ethnocentrism. Given a chance, each clan will add up its accomplishments using its own weighting system, will encounter the world with confidence in its own worth and, most importantly, will be unconcerned about comparing its accomplishments line-by-line with those of any other clan. This is wise ethnocentrism.

In the context of intelligence and I.Q. scores, we are urging that it is foolish ethnocentrism on the part of European Americans to assume that mean differences in I.Q. among ethnic groups must mean that those who rank lower on that particular dimension are required to be miserable about it—all the more foolish because the group I.Q. of the prototypical American clan, white Protestants, is some rungs from the top.

It is a difficult point to make persuasively, because the undoubted reality of our era is that group differences in intelligence are intensely threatening and feared. One may reasonably ask what point there is in speculating about some better arrangement in which it wouldn’t matter. And yet there remain stubborn counterfactuals that give reason for thinking that inequalities in intelligence need not be feared—not just theoretically, but practically.

We put it as a hypothesis that lends itself to empirical test: hardly anyone feels inferior to people who have higher I.Q.s. If you doubt this, put it to yourself. You surely have known many people who are conspicuously smarter than you are, in terms of sheer intellectual horsepower. Certainly we have. There have been occasions when we thought it would be nice to be as smart as these other people. But, like the Thai who asked, “Who wants to be an elephant?” we have not felt inferior to our brilliant friends, nor have we wanted to trade places with them. We have felt a little sorry for some of them, thinking that despite their high intelligence they lacked other qualities that we possessed and that we valued more highly than their extra I.Q. points.

When we have remarked upon this to friends, their reaction has often been, “That’s fine for you to say, because you’re smart enough already.” But we are making a more ambitious argument: it is not just people with high I.Q.s who don’t feel inferior to people with even higher I.Q.s. The rule holds true all along the I.Q. continuum.

It is hard to get intellectuals to accept this, because of another phenomenon that we present as a hypothesis, but are fairly confident can be verified: people with high I.Q.s tend to condescend to people with lower I.Q.s. Once again, put yourself to the test. Suppose we point to a person with an I.Q. thirty points lower than yours. Would you be willing to trade places with him? Do you instinctively feel a little sorry for him? Here, we have found the answers from friends to be more reluctant, and usually a little embarrassed, but generally they have been “no” and “yes,” respectively. Isn’t it remarkable: just about everyone seems to think that his level of intelligence is enough, that any less than his isn’t as good, but that any more than his isn’t such a big deal.

In other words, we propose that the same thing goes on within individuals as within clans. In practice, not just idealistically, people do not judge themselves as human beings by the size of their I.Q.s. Instead, they bring to bear a multidimensional judgment of themselves that lets them take satisfaction in who they are. Surely a person with an I.Q. of 90 sometimes wishes he had an I.Q. of 120, just as a person with an I.Q. of 120 sometimes wishes he had an I.Q. of 150. But it is presumptuous, though a curiously common presumption among intellectuals, to think that someone with an I.Q. of 90 must feel inferior to those who are smarter, just as it is presumptuous to think a white person must feel threatened by a group difference that probably exists between whites and Japanese, a gentile must feel threatened by a group difference that certainly exists between gentiles and Jews or a black person must feel threatened by a group difference between blacks and whites. It is possible to look ahead to a world in which the glorious hodgepodge of inequalities of ethnic groups—genetic and environmental, permanent and temporary—can be not only accepted but celebrated.

This difficult topic calls up an unending sequence of questions. How can intelligence be treated as just one of many qualities when the marketplace puts such a large monetary premium on it? How can one hope that people who are on the lower end of the I.Q. range find places of dignity in the world when the niches they used to hold in society are being devalued? Since the world tends to be run by people who are winners in the I.Q. lottery, how can one hope that societies will be structured so that the lucky ones do not continually run society for their own benefit?

These are all large questions, exceedingly complex questions—but they are no longer about ethnic variations in intelligence. They are about human variation in intelligence. They, not ethnic differences, are worth writing a book about—and that’s what we did. Ethnic differences must be dreaded only to the extent that people insist on dreading them. People certainly are doing so—that much is not in dispute. What we have tried to do here, in a preliminary and no doubt clumsy way, is to begin to talk about the reasons why they need not.

CHARLES MURRAY and RICHARD J. HERRNSTEIN are the authors of The Bell Curve (The Free Press), from which Parts III and IV of this essay are adapted.