What is the average black iq

I do not deny the problem of IQ gain fade-out, or the difficulty of designing successful social policies. But fade-out on IQ gains does not justify making sweeping statements that we are largely helpless to remedy social inequalities — a claim that Murray has made, in different forms, throughout his career. Work by the Nobel Prize—winning economist James Heckman has demonstrated that the best early childhood interventions have a benefit-cost ratio of somewhere between and by virtue of their effect on such things as lifelong earnings, health costs, crime, and dependence on welfare.

That finding suggests that low-income children have fewer opportunities for their genetic potential to flourish. Critics have noted that in a more recent meta-analysis by Tucker-Drob and Bates , the effect size estimated by Turkheimer et al. Furthermore, the meta-analysis tested whether Turkheimer et al. So despite the misleading impression given by the critics, the meta-analysis was a confirmation of the reduction in heritability among poor Americans.

Our piece did not contain much information about the relationship between genetic ancestry and race, but the brief paragraph that was included motivated objections, most prominently from the author Razib Khan on his blog, Gene Expression.

To back up, in the podcast, Murray states that he has changed none of his views on race and IQ since writing The Bell Curve. In fact, he says emphasis added :. Now that the genome has been sequenced and so much has been learned since it has been sequenced, the whole discussion of ethnicity-slash-race is being conducted at a much higher level of sophistication.

In reality, the racial groups used in the US — white, black, Hispanic, Asian — are such a poor proxy for underlying genetic ancestry that no self-respecting statistical geneticist would undertake a study based only on self-identified racial category as a proxy for genetic ancestry measured from DNA. But the claim is false. Controlling for multiple dimensions of ancestry derived from genome-wide genotyping is standard practice in genetic research.

I am sympathetic to this objection to pure social constructivism, and we said in our post that lay notions of race are not wrong or useless. Self-reported racial categories, coarse as they are, also generally reflect underlying differences in genetic ancestry.

For instance, in a paper by Neil Risch et al. But even this close correspondence between African ancestry, as measured from DNA, and self-reported race does not undermine our claim — race is not the same as ancestry. For one, there can be a range of ancestral backgrounds within any one self-identified racial group. If someone has any African ancestry, you can probably tell with a reasonable degree of confidence that he or she will identify as black, but the reverse is harder: If you know someone is black, you do not know what percentage African versus European versus American ancestry he or she has.

Ancestry also allows for more continuous and granular distinctions than our relatively crude categories of race. Finally, we ignore some ancestral differences and focus on others when we categorize people into races. But sometime in the past century, we stopped conceptualizing the differences between the English and the Italians in terms of race.

Currently, everything we know about the specific genetic variants associated with intelligence has been discovered in people of European ancestry, but because of these genetic differences between populations, applying genetic discoveries gleaned from one population to understand another turns out to be very difficult. As we noted in our original post, Murray uses a rhetorical move to make a genetic account of the IQ gap seem more reasonable: All Harris and Murray are saying is that the difference is probably partly genetic and partly environmental, whereas their opponents insist that it is not genetic at all.

Murray says:. And that's the assertion that is being made [by critics]. If you are going to be upset at The Bell Curve , you are obligated to defend the proposition that the black-white difference in IQ scores is percent environmental, and that's a very tough measure. Scientifically, there is no method that can apportion group differences in this way, no empirical analysis that might assign IQ differences between racial groups to one or another source, much less come up with a meaningful balance between the two.

There is not a single example of a group difference in any complex human behavioral trait that has been shown to be environmental or genetic, in any proportion, on the basis of scientific evidence. Ethically, in the absence of a valid scientific methodology, speculations about innate differences between the complex behavior of groups remain just that, inseparable from the legacy of unsupported views about race and behavior that are as old as human history.

The scientific futility and dubious ethical status of the enterprise are two sides of the same coin. To convince the reader that there is no scientifically valid or ethically defensible foundation for the project of assigning group differences in complex behavior to genetic and environmental causes, I have to move the discussion in an even more uncomfortable direction.

Consider the assertion that Jews are more materialistic than non-Jews. I am Jewish, I have used a version of this example before , and I am not accusing anyone involved in this discussion of anti-Semitism. My point is to interrogate the scientific difference between assertions about blacks and assertions about Jews. In case anyone is interested, a biological theory of Jewish behavior, by the white nationalist psychologist Kevin MacDonald, actually exists.

On the other hand, if you no longer believe this old anti-Semitic trope, is it because some scientific study has been conducted showing that it is false? Materialism is an important trait in individuals, and plausibly could be an important difference between groups. Certainly the history of the Jewish people attests to the fact that it has been considered important in groups!

But the horrific recent history of false hypotheses about innate Jewish behavior helps us see how scientifically empty and morally bankrupt such ideas really are. It is, I acknowledge, a deeply complex question, both philosophically and scientifically.

In fact, I will close by noting that not even the three of us are completely in agreement about it: I Turkheimer am convinced that the question is irredeemably unscientific; Nisbett accepts it as a legitimate scientific question, and thinks evidence points fairly strongly in the direction of the black-white gap being entirely environmental in origin; while Harden questions the quality of the existing evidence, but thinks more determinative data may be found in future genetic knowledge.

In a free country and a free academy, scientists can speculate about whatever they want, but their speculations should not be mistaken for a scientific consensus or a legitimate basis for social policy. Twitter: ent3c. Kathryn Paige Harden kph3k is associate professor in the department of psychology at the University of Texas Austin.

Richard E. Nisbett is the Theodore M. Newcomb d istinguished university professor at the University of Michigan. If you have an idea for a piece, pitch us at thebigidea vox. Our mission has never been more vital than it is in this moment: to empower through understanding. Financial contributions from our readers are a critical part of supporting our resource-intensive work and help us keep our journalism free for all.

Suppose, for example, that black and white children spoke mutually unintelligible versions of English. A test given in white English would then underestimate black children's skills and vice versa. This kind of content bias does not appear to be a significant problem for the tests discussed in this book.

If one takes a standard vocabulary test and winnows out words with unusually large black-white differences, for example, the black-white gap does not shrink much.

Likewise, if one compares black children to slightly younger white children, blacks and whites find the same words easy and difficult. Nor is the black-white gap on tests that measure familiarity with the content of American culture consistently larger than the gap on nonverbal tests that do not measure familiarity with any particular culture.

Because the racial gap in children's test performance is not confined to items that measure exposure to white language, culture, or behavior but is dramatically reduced when black children are raised in white homes, Jencks suggests that it may reflect differences in the way blacks and whites are taught to deal with what they do not know and in the emphasis they put on learning new cognitive skills.

Methodological bias arises when we assess mastery of some skill or body of information in a way that underestimates the competence of one group relative to another. Methodological bias would be important if, say, having black rather than white testers changed the relative standing of black and white test takers.

That does not appear to be the case. There is some evidence that describing a test in different ways can affect different groups' relative performance, but we do not yet know how general this is. A generation ago many egalitarians argued that using the SAT to screen applicants for selective colleges was unfair to blacks because tests of this kind underestimated black applicants' academic potential.

For most colleges, academic potential means undergraduate grades. Almost all colleges have found that when they compare black and white undergraduates who enter with the same SAT scores, blacks earn lower grades than whites, not just in their first year but throughout their college careers. Likewise, when firms compare black and white workers with the same test scores, blacks usually get slightly lower ratings from their supervisors and also do a little worse on more objective measures of job performance.

In psychological parlance, this means that tests like the SAT do not suffer from "prediction bias. The test score gap between black and white job applicants has traditionally averaged about one standard deviation. When employers do not screen workers, the performance gap is likely to be much smaller--typically more like two-fifths of a standard deviation.

The reason for this discrepancy is not that blacks perform better than whites with the same test scores. The reason is that test scores explain only 10 to 20 percent of the variation in job performance, and blacks are far less disadvantaged on the noncognitive determinants of job performance than on the cognitive ones.

Because blacks perform no better on the job than whites with similar scores, many people assume that using tests to select workers is racially fair.

But if racial fairness means that blacks and whites who could do a job equally well must have an equal chance of getting the job, a selection system that emphasizes test scores is almost always unfair to most blacks and to everyone else with low test scores. Imagine a company that has applicants for openings. Half the applicants are black and half are white. If the firm hires all applicants as temporary workers and retains those who perform best on the job, and if the performance gap between blacks and whites averages 0.

If the firm selects the applicants with the highest scores, about 13 blacks will get permanent jobs. Jencks argues that the first outcome should be our yardstick for defining racial fairness. Using this yardstick, the second system is clearly biased against blacks. In effect, Jencks says, the second system forces blacks to pay for the fact that social scientists have unusually good measures of a trait on which blacks are unusually disadvantaged.

When the U. Army launched the world's first large-scale mental testing program in , it found that whites scored substantially higher than blacks. Biological determinists immediately cited these findings as evidence that whites had more innate ability than blacks, but cultural determinists quickly challenged this interpretation. By the late s most social scientists seem to have been convinced that either genetic or cultural factors could explain the gap.

Neither side had a convincing way of separating the effects of heredity from the effects of culture, so the debate was an empirical standoff. After the horrors of the Holocaust made all genetic explanations of human differences politically suspect. Once the U. Supreme Court declared de jure racial segregation unconstitutional in , genetic explanations of racial differences became doubly suspect because they were identified with southern resistance to desegregation.

As a result, environmentalism remained hegemonic throughout the s. Then in Arthur Jensen published an article in the Harvard Educational Review arguing that educational programs for disadvantaged children initiated as part of the War on Poverty had failed, and that the black-white test score gap probably had a substantial genetic component?

Jensen's argument went roughly as follows:. Jensen's article created such a furor that psychologists once again began looking for evidence that bore directly on the question of whether racial differences in test performance were partly innate. Richard Nisbett reviews their findings in chapter 3. Two small studies have tried to compare genetically similar children raised in black and white families.

Elsie Moore found that black children adopted by white parents had IQ scores Lee Willerman and his colleagues compared children with a black mother and a white father to children with a white mother and a black father. The cleanest comparison is for mixed-race children who lived only with their mother. Mixed-race children who lived with a white mother scored 11 points higher than mixed-race children who lived with a black mother. Since the black-white IQ gap averaged about 15 points at the time these two studies were done, they imply that about four-fifths of that gap was traceable to family-related factors including schools and neighborhoods.

A better-known study dealt with black and mixed-race children adopted by white parents in Minnesota. The mixed-race children were adopted earlier in life and had higher IQ scores than the children with two black parents. When the 29 black children were first tested, they scored at least ten points higher than the norm for black children, presumably because they had more favorable home environments than most black children.

When these children were retested in their late teens or twenties, their IQ scores had dropped and were no longer very different from those of Northern blacks raised in black families. The most obvious explanation for this drop is that the adoptees had moved out of their white adoptive parents' homes into less favorable environments.

But because the study did not cover black or mixed-race children adopted by black parents, it does not seem to us to provide strong evidence on either side of the heredity-environment debate.

Race is not a well-defined biological category. It is a social category, whose biological correlates vary geographically and historically. America has traditionally classified people as black using the "one drop" rule, under which anyone with known black ancestors is black. As a result, people are often treated as black even though they have a lot of European ancestors.

If blacks with a lot of European ancestors had the same test scores as those with no European ancestors, we could safely conclude that the black-white test score gap was a by-product of social classification rather than heredity. But when we find that light-skinned blacks score higher than dark-skinned blacks, we cannot rule out the possibility that this difference is environmental.

Light skin has traditionally been a social asset for black Americans, and the correlation between light skin and test performance could reflect this fact. To get around this problem, we need less visible genetic markers. Two studies have used blood markers to estimate the percentage of Europeans in a black child's family tree. Neither study found a correlation between the number of "European" blood markers and IQ.

Although racially mixed children are culturally black in America, and are almost always raised by black parents in black communities, this is not true everywhere. Klans Eyferth studied the illegitimate children of black and white soldiers stationed in Germany as part of the army of occupation after World War II.

All these children were raised by their German mothers. There was considerable prejudice against blacks in Germany at the time, and any child of a German mother who looked black was also presumed to be illegitimate, which carried additional stigma. But mixed-race German children did not attend predominantly black schools, live in black neighborhoods, or presumably have predominantly black or mixed-race friends.

When Eyferth gave these children a German version of the Wechsler IQ test, children with black fathers and white fathers had almost identical scores. Taken in isolation, none of these studies would carry much weight. The samples are small, and the comparisons could be distorted by unmeasured genetic or environmental influences.

But Nisbett argues that their consistency gives them far more weight that they would have if taken one by one. We agree. We read these studies as supporting three tentative conclusions:. These studies do not prove that blacks and whites would have exactly the same test scores if they were raised in the same environment and treated the same way. But we find it hard to see how anyone reading these studies with an open mind could conclude that innate ability played a large role in the black-white gap.

This is not easy. Hundreds of different family characteristics correlate with children's test performance. In any event, schools cannot be the main reason for the black-white test score gap, because it appears before children enter school and persists even when black and white children attend the same schools. If schools play an important role in perpetuating the gap, either desegregated schools must be treating black and white children very differently or else black and white children must react very differently to the same treatment.

There is no direct genetic evidence for or against the theory that the black-white gap is innate, because we have not yet identified the genes that affect skills like reading, math, and abstract reasoning. Studies of mixed-race children and black children adopted by white parents suggest, however, that racial differences in test performance are largely if not entirely environmental in origin.

Cultural differences associated with chronic poverty may account for some of the black-white test score gap, but they cannot be the main explanation, since the gap persists among affluent children. And while children raised by single mothers score lower on most standardized tests than children raised by married couples, this difference almost disappears once we take account of the fact that women who become single mothers come from less advantaged families, have lower test scores, and complete less schooling than women with husbands.

We suspect that successful new explanations for the test score gap will differ from their predecessors in several ways. Second, instead of looking mainly for resource differences between predominantly black and predominantly white schools, successful theories will probably have to look more carefully at the way black and white children respond to the same classroom experiences, such as being in a smaller classroom, having a more competent teacher, having a teacher of their own race, or having a teacher with high expectations for those who perform below the norm for their age group.

Successful theories will therefore have to pay more attention to psychological and cultural influences, which are much harder to measure than income, education, and living arrangements. It might well require an investment of time and effort comparable to the effort that went into developing cognitive tests during the first half of the 20th century. Our argument that reducing the black-white test score gap would do more to move America toward racial equality than any politically plausible alternative rests on two problematic premises: that policies aimed at reducing the test score gap are in fact politically feasible and that such policies can in fact reduce the gap.

Public support for almost any policy depends partly on whether the beneficiaries are perceived as deserving or undeserving. First graders of every race seem eager to please. Both black and white adults often think that older black children lack academic motivation, but most adults still blame this on the children s parents or schools, not on the children themselves.

That was why Lyndon Johnson emphasized helping children in his original war on poverty. Both school desegregation and eliminating academically selective classes at desegregated schools have aroused strong white resistance because of the perceived cost to white children. But these policies would not do blacks much good even if whites were willing to adopt them.

All these changes would benefit both blacks and whites, but all appear to be especially beneficial for blacks. The experiment also found that gains were much larger for blacks than for whites. Historical evidence also seems to support the hypothesis that the black-white test score gap falls when class size falls. When low birth rates reduced school enrollment in the s, the teacher-pupil ratio rose and classes shrank. Independent analyses by Ronald Ferguson and David Grissmer suggest that this change in class size was followed by a marked decline in the black-white test score gap.

Since the teachers who fail such tests are concentrated in black schools, such exams would probably prove especially beneficial to black students, although this benefit may be partially offset by the fact that the teachers who fail such tests are also disproportionately black.

But Ferguson also finds some evidence that low teacher expectations have a more negative effect on black children than on their white classmates. Research also suggests that black-white differences in parenting practices contribute to the test score gap.

Improving parenting skills may therefore be as important as improving schools. The puzzle is how to proceed.