Blog Post

All Brains Are the Same Color

Am I a hopeless optimist? Is the era of 'bad science' finally turningto one where sane, thoughtful, even visionary generalizations areflowing from all of the great computational findings that should makethis one of humanity's great intellectual eras? If only our dopeyprejudices didn't get in the way. . . This is a reblog of a superb summary article on race and IQ by Richard E. Nisbett, a professor of psychology at the University ofMichigan, and author of ?The Geography of Thought: How Asians andWesterners Think Differently and Why.? It is the most concise treatment of sloppy generalizations about IQ and the "genetics" of race that I've seen in a long time, pointing out significant flaws in some of the data and its (mis)interpretations and pointing to a list of excellent studies which underscore how crucial environment is to just about everything humans do, including how they test on IQ tests. All this, and a clear, unhyperbolic, and yet powerful prose. In this amazing year on leave, where I read wherever curiosity takes me (this is part of the "method" of unlearning I'm advocating, incidentally), the next book on my reading list will be "The Geography of Thought." I'll review it on this blog after I finish. In the meantime, a reblog from the December 9, 2007 New York Times (NYTimes.com), "All Brains are the Same Color," by Richard E. Nisbett, for your Monday morning reading pleasure. I know you are tired of hearing me talk about fishing but, hey, THIS one is a keeper: http://www.nytimes.com/2007/12/09/opinion/09nisbett.html?ex=1197867600&e...

 

December 9, 2007
Op-Ed Contributor

All Brains Are the Same Color

Ann Arbor, Mich.

JAMES WATSON, the 1962 Nobel laureate, recently asserted that he was?inherently gloomy about the prospect of Africa? and its citizensbecause ?all our social policies are based on the fact that theirintelligence is the same as ours ? whereas all the testing says notreally.?

Dr. Watson?s remarks created a huge stir because they implied thatblacks were genetically inferior to whites, and the controversyresulted in his resignation as chancellor of Cold Spring HarborLaboratory. But was he right? Is there a genetic difference betweenblacks and whites that condemns blacks in perpetuity to be lessintelligent?

The first notable public airing of the scientific question came in a1969 article in The Harvard Educational Review by Arthur Jensen, apsychologist at the University of California, Berkeley. Dr. Jensenmaintained that a 15-point difference in I.Q. between blacks and whiteswas mostly due to a genetic difference between the races that couldnever be erased. But his argument gave a misleading account of theevidence. And others who later made the same argument ? RichardHerrnstein and Charles Murray in ?The Bell Curve,? in 1994, forexample, and just recently, William Saletan in a series of articles onSlate ? have made the same mistake.

In fact, the evidence heavily favors the view that race differences in I.Q. are environmental in origin, not genetic.

The hereditarians begin with the assertion that 60 percent to 80percent of variation in I.Q. is genetically determined. However, mostestimates of heritability have been based almost exclusively on studiesof middle-class groups. For the poor, a group that includes asubstantial proportion of minorities, heritability of I.Q. is very low,in the range of 10 percent to 20 percent, according to recent researchby Eric Turkheimer at the University of Virginia. This means that forthe poor, improvements in environment have great potential to bringabout increases in I.Q.

In any case, the degree of heritability of a characteristic tells usnothing about how much the environment can affect it. Even when a traitis highly heritable (think of the height of corn plants), modifiabilitycan also be great (think of the difference growing conditions can make).

Nearly all the evidence suggesting a genetic basis for the I.Q.differential is indirect. There is, for example, the evidence thatbrain size is correlated with intelligence, and that blacks havesmaller brains than whites. But the brain size difference between menand women is substantially greater than that between blacks and whites,yet men and women score the same, on average, on I.Q. tests. Likewise,a group of people in a community in Ecuador have a genetic anomaly thatproduces extremely small head sizes ? and hence brain sizes. Yet theirintelligence is as high as that of their unaffected relatives.

Why rely on such misleading and indirect findings when we have muchmore direct evidence about the basis for the I.Q. gap? About 25 percentof the genes in the American black population are European, meaningthat the genes of any individual can range from 100 percent African tomostly European. If European intelligence genes are superior, thenblacks who have relatively more European genes ought to have higherI.Q.?s than those who have more African genes. But it turns out thatskin color and ?negroidness? of features ? both measures of the degreeof a black person?s European ancestry ? are only weakly associated withI.Q. (even though we might well expect a moderately high associationdue to the social advantages of such features).

During World War II, both black and white American soldiers fatheredchildren with German women. Thus some of these children had 100 percentEuropean heritage and some had substantial African heritage. Tested inlater childhood, the German children of the white fathers were found tohave an average I.Q. of 97, and those of the black fathers had anaverage of 96.5, a trivial difference.

If European genes conferred an advantage, we would expect that thesmartest blacks would have substantial European heritage. But when agroup of investigators sought out the very brightest black children inthe Chicago school system and asked them about the race of theirparents and grandparents, these children were found to have no greaterdegree of European ancestry than blacks in the population at large.

Most tellingly, blood-typing tests have been used to assess thedegree to which black individuals have European genes. The blood groupassays show no association between degree of European heritage and I.Q.Similarly, the blood groups most closely associated with highintellectual performance among blacks are no more European in originthan other blood groups.

The closest thing to direct evidence that the hereditarians have isa study from the 1970s showing that black children who had been adoptedby white parents had lower I.Q.?s than those of mixed-race childrenadopted by white parents. But, as the researchers acknowledged, thestudy had many flaws; for instance, the black children had been adoptedat a substantially later age than the mixed-race children, and laterage at adoption is associated with lower I.Q.

A superior adoption study ? and one not discussed by thehereditarians ? was carried out at Arizona State University by thepsychologist Elsie Moore, who looked at black and mixed-race childrenadopted by middle-class families, either black or white, and found nodifference in I.Q. between the black and mixed-race children. Mosttelling is Dr. Moore?s finding that children adopted by white familieshad I.Q.?s 13 points higher than those of children adopted by blackfamilies. The environments that even middle-class black children growup in are not as favorable for the development of I.Q. as those ofmiddle-class whites.

Important recent psychological research helps to pinpoint just whatfactors shape differences in I.Q. scores. Joseph Fagan of Case WesternReserve University and Cynthia Holland of Cuyahoga Community Collegetested blacks and whites on their knowledge of, and their ability tolearn and reason with, words and concepts. The whites had substantiallymore knowledge of the various words and concepts, but when participantswere tested on their ability to learn new words, either from dictionarydefinitions or by learning their meaning in context, the blacks didjust as well as the whites.

Whites showed better comprehension of sayings, better ability torecognize similarities and better facility with analogies ? whensolutions required knowledge of words and concepts that were morelikely to be known to whites than to blacks. But when these kinds ofreasoning were tested with words and concepts known equally well toblacks and whites, there were no differences. Within each race, prior knowledge predicted learning and reasoning, but between the races it was prior knowledge only that differed.

What do we know about the effects of environment?

That environment can markedly influence I.Q. is demonstrated by theso-called Flynn Effect. James Flynn, a philosopher and I.Q. researcherin New Zealand, has established that in the Western world as a whole,I.Q. increased markedly from 1947 to 2002. In the United States alone,it went up by 18 points. Our genes could not have changed enough oversuch a brief period to account for the shift; it must have been theresult of powerful social factors. And if such factors could producechanges over time for the population as a whole, they could alsoproduce big differences between subpopulations at any given time.

In fact, we know that the I.Q. difference between black and white12-year-olds has dropped to 9.5 points from 15 points in the last 30years ? a period that was more favorable for blacks in many ways thanthe preceding era. Black progress on the National Assessment ofEducational Progress shows equivalent gains. Reading and mathimprovement has been modest for whites but substantial for blacks.

Most important, we know that interventions at every age from infancyto college can reduce racial gaps in both I.Q. and academicachievement, sometimes by substantial amounts in surprisingly littletime. This mutability is further evidence that the I.Q. difference hasenvironmental, not genetic, causes. And it should encourage us, as asociety, to see that all children receive ample opportunity to developtheir minds.

Richard E.Nisbett, a professor of psychology at the University of Michigan, isthe author of ?The Geography of Thought: How Asians and WesternersThink Differently and Why.?

 

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3 comments

Are we harking back to Jefferson's Notes on the State of Virginia?

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None of the Above

What I.Q. doesn

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December 16, 2007
Letters

The I.Q. Gap: Culture Trumps Genes

To the Editor:

Richard E. Nisbett (

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