On The Trail of the Great Taboo

The IQ Controversy, Mark Snyderman and Stanley Rothman, Transaction Publishers, 1988, 310 pp.

Few subjects excite as much controversy as the question of IQ testing. Is intelligence inherited or determined by environment? Why do the children of rich people have higher IQ scores than the children of poor people? Why do whites and Asians have higher scores than blacks and Hispanics? These questions are treated with the caution one might reserve for vials of nitroglycerin.

As Mark Snyderman and Stanley Rothman show in their book, The IQ Controversy, Public Policy and the Media, what the press and television tell us about IQ is different from what specialists in the field say about it. The media refuse to accept the scientific consensus and instead promote positions that are considered eccentric in the expert community. Mr. Snyderman and Mr. Rothman base their conclusions on a careful study of the scholarly literature, an analysis of mass media reports on IQ, and a questionnaire survey of 661 recognized authorities in education and psychological testing.

The media support the view that intelligence can’t be either defined or measured, that intelligence tests — whatever they measure — are hopelessly biased, and that test score differences reflect the test taker’s environment rather than inherited ability. They take as an article of faith that the differences in average IQs of blacks and whites is strictly a matter of environment.

The popular media do concede that there are people like Arthur Jensen and Richard Herrnstein who dissent from some of these views, but it presents them either as cranks or racists. In fact, as the authors demonstrate, both these men are entirely within the scientific mainstream and are unusual only in their willingness to speak publicly.

It is true that intelligence is hard to define. It is one of those things that we may not be able to describe perfectly but that we recognize. More to the point, IQ tests have an impressive record of accurately predicting school grades, job performance, or anything else that requires what people think of as intelligence. Anyone who scores well on IQ tests is likely to seem intelligent by virtually any common-sense standard.

Furthermore, IQ develops in a predictable, virtually physiological way. By about the age of eight, a child’s IQ is well established and his test scores of many years later can be predicted with 90% accuracy or better. Intelligence develops with at least as much regularity as purely physical characteristics like height and weight.

Intelligence, therefore, need not be perfectly defined in order for it to be measured. Whatever it is that IQ tests measure, a good majority of Mr. Snyderman and Mr. Rothman’s experts agree that it is an important ingredient to success in life, and that IQ tests measure it reliably.

Heritability, on the other hand, is easy to define but can be hard to measure. Some things, like eye color, are strictly genetic; no environment can change them. Height is largely genetic, but can be influenced by diet, which is part of the environment. Although the popular press writes about the IQ debate as if people were arguing that intelligence is either all genetic or all environmental, virtually every expert agrees that intelligence is influenced by both genes and environment. The only question is by how much.

The best subjects for studies of the heritability of IQ are identical twins, since they have exactly the same genes. When identical twins are separated at birth and reared apart they still grow up to have very similar IQs, even though their environments were different. In fact, separated identical twins are closer in IQ than are fraternal twins who are reared in the same family. Fraternal twins have no more genetic overlap than any pair of brothers or sisters, but when they are reared in the same family, they have environments that are about as similar as it is possible to get. That their IQ scores should differ significantly more than those of identical twins who didn’t even grow up in the same family suggests that heredity is more important than environment in determining IQ.

Other studies have shown that the IQs of adopted children are closer to those of their biological parents than to those of their foster parents. Likewise, in a family whose children are all adopted, there will be a greater variation in IQ than in a family whose children are all biological. Biological children have genes in common as well as environment, and genes appear to account for their closer IQ scores.

Most scientists in the Snyderman-Rothman survey therefore think that about 60% of individual differences in IQ are due to genes and the rest to environment, and some put the genetic contribution as high as 80%. This does not mean that IQ cannot change. To the extent that it is influenced by environment, a massively different environment can presumably affect it.

However, no one is sure of the best ways to change the environment in order to improve IQ, and since more then half of individual IQ differences appear to be due to genes anyway, environment changes have to be drastic to have any effect.*

Moreover, there is no assurance that changes would be permanent. The most intensive Head Start programs reportedly raise preschool children’s IQs by as much as 15 or 20 points, but the gains usually disappear by the second or third grade. Even if all IQ differences due to environment could somehow be eliminated, the differences due to heredity would remain. Also, if new environmental techniques to raise IQ were ever discovered, they would be likely to work just as well for people who have high IQs by virtue of their genes. Differences in IQ score are therefore something that will persist no matter how carefully environment is adjusted.

The heredity/environment question is also part of the debate over the link between IQ and success in life. Everyone agrees that smart, successful people tend to have smart, successful children. People who think IQ is mainly influenced by environment argue that this is because successful people give their children a good environment. They point out that children who grow up in $200,000 houses have higher IQs than children who grow up in $30,000 houses. They come close to suggesting that a more expensive house would raise a child’s IQ. People who think that IQ is largely hereditary argue that people are successful because they have high IQs, and are likely to pass on genes for high IQ to their children.

Test data show that for every social and economic class, if a son has a higher IQ than his father he is likely to move up and if his IQ is lower he is likely to move down. IQ thus appears to affect social class more than the reverse.

Racial differences in test scores are, of course, the touchiest issue in the whole IQ debate. Ever since the First World War, when large numbers of Americans first started taking IQ tests, average black scores have been about 15 points lower than white scores. With an average IQ of 85, only 16% of the black population scores over 100, while half the white population does. What accounts for these differences?

The most common explanation in the popular press is that the tests are “culturally” biased against blacks. To make the case for bias it must be shown that there are specific, culture-oriented test problems that blacks consistently get wrong. However, in modern IQ tests there are no questions that only one racial group has particular trouble answering. Anyone who argues that the tests are biased must therefore prove a very difficult case: that every single question on the tests is equally biased.

Furthermore, if intelligence tests are culturally biased, it should be possible to devise a reliable test that is not biased. Despite repeated attempts to do so, no one has been able to develop a meaningful intelligence test on which blacks and whites score equally. Finally, if the tests are biased against blacks they are presumably biased against Asians as well. In fact, Asians have higher average IQ scores than whites, but no one ever suggests that the tests are culturally biased in their favor. IQ and aptitude tests also tend to be almost equally valid for people of all races. They can predict the grades a child will get or how well an adult will do at a job, no matter what his race.

Another popular explanation for low black IQ scores is that blacks come from deprived environments. This undoubtedly has an effect on IQ. However, even when blacks and whites have the same backgrounds, in terms of family income and childhood advantages, blacks still have average IQ scores 12 to 15 points lower than comparable whites. American Indians and Mexican Americans often live in circumstances that are even more meager than those of blacks. Nevertheless, both groups consistently score better on IQ tests than blacks.

In cases where black children have been adopted by white parents, test results are the same as in other adoption studies: The children’s IQs may be improved by environment, but they are still closer to those of their biological parents than to those of their adoptive parents. Finally, it would be hard to deny that racial oppression of blacks has receded dramatically over the last 60 or 70 years. Nevertheless, the racial IQ gap has been stuck at 15 points for the entire period, suggesting that environment — at least white malevolence — by no means explains all of it.

The majority of the experts polled by Mr. Snyderman and Mr. Rothman therefore conclude that genetic differences account for at least part of the black/white IQ difference. Only 15% said they thought that the differences were due to environment alone. Since the race/IQ question is the most politically explosive one in all the social sciences, it is highly significant that only a small minority took the safe, liberal position.

If the experts are in rough agreement on the heritability of IQ, and acknowledge that genes account for at least part of the IQ differences between different races, why do the media continue to distort their views? After a thorough study of press stories about IQ and a series of interviews with editors, the authors conclude that the media simply write what they wish were true about IQ rather than what the experts say. And, to be sure, they can always find some experts, notably Professors Leon Kamin and Steven Jay Gould, who are prepared to argue a strictly environmental position. It suits the bias of the media to present men like these as typical of the scientific community, whereas they are a maverick minority.

The experts themselves are partly to blame. Mr. Snyderman and Mr. Rothman put it this way: “[T]he expert community has more or less accepted such distortions as inevitable. Since their scientific findings run counter to a conventional wisdom whose supporters are quite passionate, they have accepted a tradeoff that permits them to publish their findings in professional journals, but not for popular consumption. Under such circumstances they can continue their scientific work without the fear of being pilloried by the larger community and of being deprived of grants for research by government agencies and private foundations. So fully have many experts accepted this arrangement that they are angered by colleagues with whom they agree but who popularize their views and threaten their scientific work.”

In other words, experts are happy to talk honestly about IQ among themselves, but don’t want anyone else to hear. The liberal fury that the facts about IQ inevitably unleashes disturbs their academic tranquility.

On the other hand, it is easy to understand why people prefer not to hear the expert view. Many people so dislike the idea that there may be genetic limits to achievement that they simply refuse to consider the evidence for it. Others fear that if it is acknowledged that much of the IQ difference between blacks and whites is genetic, it will somehow lead to the preposterous notion that all blacks have lower IQs than all whites. Blacks are reluctant to consider the possibility that their failures may be due to their own shortcomings rather than to white oppression. The faint-hearted just keep silent. All this results in the enshrinement of a theory of equality that is agreeable but for which there is scarcely any evidence.

America therefore operates according to a political view of reality that willfully ignores the opinions of the best informed. Egalitarians, and their allies in the press, are vehement in insisting that racial oppression alone accounts for differences in black/white achievement. It is only by disregarding — even reviling — expert opinion that affirmative action, quotas, and the rest of the racial preference industry can be justified. Gruesome distortions result.

For example, intelligence tests have long been used to decide which school children should be in gifted classes and which should be in classes for slow learners. Although black/white IQ scores overlap in the middle ranges, there are striking differences at the high and low ends. Blacks are six times as likely to have IQs of 50 to 70, which put them in the slow learner category, while whites are 10 times more likely to score 130 or over.

Egalitarians refuse to accept the best, scholarly explanations for these differences, and promote the only explanation they find acceptable: test bias. It was on this basis that a federal judge in California ruled that any test that detected racial differences was, by definition, biased. He forbade the use of IQ tests for black school children (but not for children of any other race) and ordered that children of all races be put into gifted and slow learners classes in strict proportion to their population. Narrow, anti-scientific thinking of this kind forces children into the wrong classes and thwarts learning for all. In the long run, of course, whites simply abandon the public schools.

Affirmative action programs, which lower standards for minorities, are based on a similarly willful disregard for expert opinion. They assume that blacks are just as intelligent and hard-working as whites and that the only reason they have not achieved as much is because of America’s history of racism. Even if one were to accept this theory, most Americans think it is wrong to punish today’s whites for the presumed sins of yesterday’s whites. But if, as the evidence suggests, the distribution of intelligence among blacks is not the same as for whites, racial preference programs are not just unfair to whites; they are doomed to failure.

The great irony of intelligence testing is that one of its original purposes was to get rid of subjective bias so as to distribute jobs and schooling purely on the basis of ability. It helped break down class and social divisions. To criticize testing because it does not produce the results one wants is like killing the messenger because he brings bad news. Racial preference programs have brought back precisely the arbitrary decision-making that objective testing was designed to eliminate. Policy makers have been greatly influenced by closed-minded editors and television producers who ignore the experts and refuse to listen to disagreeable truths.

In Notes on Virginia, Thomas Jefferson wrote, “It is error alone which needs the support of government. Truth can stand by itself.” President Jefferson made the mistake of thinking he could count on the press to help the truth prevail.