By Andrew D. Thibedeau

Intelligence and How to Get It: Why Schools and Cultures Count
By Richard E. Nisbett
W.W. Norton, 2009


A century of IQ  testing defies our egalitarian hopes that all men are created equal. To many, this is common sense: some are born with the stuff of genius, while the rest of us must accept our intellectual mediocrity. This hereditarian view of human intelligence has been used to explain the fact that people score differently on IQ tests. IQ scores do not vary uniformly, but stratify along two interrelated dimensions: class and race. Hereditarians argue that racial minorities and the poor have lower IQs because they lost at genetic roulette. In Intelligence and How to Get It: Why Schools and Cultures Count, University of Michigan professor Richard E. Nisbett is unpersuaded by this kind of genetic fatalism, and in its place offers a theory that holds social, economic, and cultural factors to be the principal determinants of the human intellect.

To follow Nisbett's argument, it is necessary to think of intelligence in terms of IQ-a notion rather out of vogue in today's age of multiple intelligences and "emotional IQ."  To begin, he offers a vague definition of intelligence (can there be any other kind?) that encompasses the ability to reason, solve problems, and think abstractly.  A slippery concept difficult to examine quantitatively, intelligence is made the tangible object of analysis by means of the IQ test.[1] As it turns out, exactly how well different IQ tests measure "intelligence" is mostly unimportant on account of one statistical observation: the results of all IQ tests positively correlate with each other.  In other words, people who score well on one IQ test usually score well on every IQ test.  What matters here is not the elegant correlation itself, but its necessary implication: that intelligence is a real cognitive faculty that can be measured, if only indirectly.

What's more, Nisbett explains, strong evidence tells us that intelligence as measured by IQ is the single best predictor of future performance in school and in the workplace, as well as an individual's chances of dropping out of school, divorcing, being unemployed, or having illegitimate children.[2] However uncomfortable one finds reducing the human intellect to a single metric, IQ has clear utility. The central question of Nisbett's book-whether or not IQ is susceptible to environmental influence and intervention-is therefore one of highest scientific and social import. To answer this question, he teases apart the complex lattice of class, race, biology, and culture, so that he might reveal how they impact IQ.

Nisbett first takes a close look at what he calls the "cognitive cultures" that demarcate racial and socioeconomic groups.  He finds that working-class parents are more likely to raise their children in punitive and stressful ways.  On average, children in working-class homes will hear two encouraging comments for each reprimand they incur.  For the children of welfare-dependant, African American mothers, every encouraging comment is accompanied by two reprimands.  Middle-class parents, on the other hand, give six encouragements for every reprimand.  The evidence shows that middle-class parents speak an average of 2,000 words per hour to their children.  By age three, they have heard about 30 million words.  Working-class children hear about 1,300 words per hour-20 million words by age three and a vocabulary a third smaller than middle-class children.  Children of poor, African American mothers hear a mere 600 words per hour.

Add to this parade of horribles the corrosive impact of racial prejudice. Among manifold injustices, endemic racism restricts African Americans' career trajectories.  More often than not, studies show, employers choose less-qualified white applicants over better-qualified African American applicants.  This discounts the value of African Americans' qualifications, reducing the incentive to obtain those qualifications.  Taken together, these factors form the solid basis upon which Nisbett concludes that the divergence of IQ scores along racial and socioeconomic lines is environmental in origin.

Throughout the book, Nisbett draws on a body of empirical work to refute claims that population differences in IQ scores-particularly the gap between white and African American IQ scores-are inborn.  If it were true that European genes made for higher IQs, he reasons, individuals with a higher percentage of European ancestry would score higher on IQ tests.  Looking at several studies comparing the IQs of individuals with differing fractions of European heritage, Nisbett finds no link between European genes and higher IQ.  As further evidence that IQ differences are not genetic, he points to the so-called Flynn effect, the widespread upward trend in IQ scores documented by intelligence researcher James R. Flynn.  Flynn has observed an average 18 point rise in IQ over the past half century.  It is impossible that genes account for this increase.  Fifty years is simply too short a time for natural selection to produce such a seismic shift in the human genome.

Having established the environmental basis for population-wide differences in IQ, the remainder of Nisbett's book addresses the question of how to fix them.  His answer: education.  Examining the best research available, Nisbett draws some tentative conclusions.  Overall, blind investment, voucher programs, charter schools, and teacher certification requirements do not improve student achievement.  On the other hand, teacher experience and quality count for a lot.  Limited research suggests that incentive programs that reward successful teachers correlate with higher student achievement.

It should come as no surprise that the most successful educational initiatives are those that aim, in effect, to recreate a "middle-class" environment for underprivileged children.   Focusing on early childhood, these programs engage the children using the best-available developmental aids and educational toys and provide intensive lessons and activities designed to cultivate the children's cognitive, linguistic, and social faculties.  The children are given good nutrition and quality medical care.  Teachers meet routinely with parents, encourage them to become involved in their child's education, and program staff actively works to promote stability and reduce conflict and stress in the home.

The results of even the best of these programs have been mixed. While high gains in IQ are observed at the end of the programs, these fade with time.  Nevertheless, Nisbett argues that the value in these programs can be found in the other, sustained achievement gains that were observed.  For example, participants in these programs were less likely to repeat grades, more likely to do well on standardized tests, more likely to finish high school, less likely to have problems with delinquency, and less likely to become dependant on welfare. 

The only significant shortcoming of Nisbett's book is its uncritical use of race.  Because he undertakes to explain the IQ gap between "black" and "white" populations, race is necessarily one of the principal objects of his analysis.  In light of decades of genetic research, however, the consensus is that "the idea of discrete races in the typological mindset of past centuries clearly does not apply to humans."[3]  That racial distinctions have no genetic basis does not negate the existence of race.  To the contrary, race is a potent sociocultural phenomenon that exercises great force in people's lives.  It is this theory of race-race as cultural construct-that provides the conceptual foundation for Nisbett's focus on racially-defined populations.  He uses race as a proxy meant to capture the complex dimensions of a sociocultural reality.

While Nisbett's use of race is therefore conceptually defensible, no such defense appears in his book.  He simply presents his subject as "IQ in Black and White."  Next to his nuanced discussion of intelligence and genetics, his ubiquitous use of an outmoded racial typology seems almost clumsy.  Perhaps worse, it implicitly "favors the default assumption that racial differences are genetic in origin."[4]  This marks Nisbett's book with a tacit racial essentialism and detracts from his central conclusion that biology alone is not the principal determinant of human intelligence.

Overall, Nisbett's book is a timely and illuminating contribution to the discussion of race, class, and intelligence.  He presents a strong counterpoint to the hereditarian view of intelligence and supports his claims with ample research and solid reasoning.  His discussion of how to improve education is limited by the paucity of reliable research in that area.  While more research must be done, Nisbett's ultimate conclusion is a sound and important one: brains are not the prize of a genetic lottery, but products of environments over which we have control.  To make the best of that control, the evidence suggests we put our resources toward creating richer "cognitive cultures" for all children: by educating parents, intervening to fix broken systems, and placing renewed emphasis on early-childhood education.  This, then, is why schools and cultures count.              



Andrew D. Thibedeau, JD, joined CRG as a Fellow in June of 2009.  Andrew graduated from the Suffolk University Law School in 2008 where he served as editor of the Journal of Trial and Appellate Advocacy. Previously, he spent two years as a legal assistant to Thomas M. Sobol, working principally in pharmaceutical class action litigation.




1 The first such tests, designed at the turn of the last century, gauged intelligence by dividing a person's "mental" age by their chronological age, hence intelligence quotient.

2 As Judge Leon R. Yankwich observed: "[T]here are no illegitimate children, only illegitimate parents."  Contest Over Children Ends, L.A. Times, Aug. 9, 1928, at A8.

3 John H. Relethford, Race and Global Patterns of Phenotypic Variation, 139 Am. J. of Physical Anthropology 16, 20 (2009).

4 Clarence C. Gravlee, How Race Becomes Biology: Embodiment of Social Inequality, 139 Am. J. of Physical Anthropology 47, 49 (2009).

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