Nicholas Kristof has an op-ed today, How to Raise Our I.Q. He opens with a standard version of the individual meritocracy argument, that IQ is largely inherited:
Poor people have I.Q.’s significantly lower than those of rich people, and the awkward conventional wisdom has been that this is in large part a function of genetics. After all, a series of studies seemed to indicate that I.Q. is largely inherited. Identical twins raised apart, for example, have I.Q.’s that are remarkably similar. They are even closer on average than those of fraternal twins who grow up together.
If intelligence were deeply encoded in our genes, that would lead to the depressing conclusion that neither schooling nor antipoverty programs can accomplish much. Yet while this view of I.Q. as overwhelmingly inherited has been widely held, the evidence is growing that it is, at a practical level, profoundly wrong.
Kristof cites Richard Nisbett’s new book Intelligence and How to Get It: Why Schools and Cultures Count. I covered some of Nisbett’s work in the post IQ, Environment and Anthropology, and Jim Holt gave a strong review of the book recently in the NY Times. The publisher’s home page simply says that this book is a “bold refutation of the belief that genes determine intelligence.”
From the damning research of The Bell Curve to the more recent controversy surrounding geneticist James Watson’s statements, one factor has been consistently left out of the equation: culture…
World-class social psychologist Richard E. Nisbett takes on the idea of intelligence as something that is biologically determined and impervious to culture— with vast implications for the role of education as it relates to social and economic development. Intelligence and How to Get It asserts that intellect is not primarily genetic but is principally determined by societal influences.
Well, not quite. As Kristof notes, “While I.Q. doesn’t measure pure intellect — we’re not certain exactly what it does measure — differences do matter, and a higher I.Q. correlates to greater success in life. Intelligence does seem to be highly inherited in middle-class households, and that’s the reason for the findings of the twins studies: very few impoverished kids were included in those studies. But Eric Turkheimer of the University of Virginia has conducted further research demonstrating that in poor and chaotic households, I.Q. is minimally the result of genetics — because everybody is held back. ‘Bad environments suppress children’s I.Q.’s,’ Professor Turkheimer said.”
First, for those interested in understanding IQ measures, I strongly recommend Greg’s posts Girls Closing Math Gap? Troubles with Intelligence 1 and The Flynn Effect: Troubles with Intelligence 2. In the first post, Greg takes on the idea of “natural” differences in male/female math ability, discusses problems with how IQ gets measured, and discusses how the “changing status of women seems to correlate pretty strongly with the math gap.” In the second post, Greg discusses James Flynn’s work on the steadily rising IQ scores seen around the world, what intelligence actually means, and how best to measure it.
Turning to the inequality side, Kristof’s point is that on a level-playing field genetics can become a primary factor in IQ scores. But just like low-quality nutritional environments can lead to stunting of physical growth, so too can unequal environments stunt the growth of brain function and intellectual growth, as we’ve written about before in Poverty Poisons the Brain and Poverty and the Brain: Becoming Critical.
Eric Turkheimer has a recent paper with K. Paige Harden and John Loelin entitled, Genotype by Environment Interaction in Adolescents’ Cognitive Aptitude (pdf). Using 839 twin pairs from a range of socioeconomic backgrounds, the paper shows that “Shared environmental influences were stronger for adolescents from poorer homes, while genetic influences were stronger for adolescents from more affluent homes.” In an accompanying press article, Turkheimer says “[This research] suggests that if you’re going to work with people’s environment to try and increase IQ, then the place to invest your money is in taking people in really bad environments and making them OK, rather than taking people in pretty good environments and making it better.”
Better outcomes are also a concern for Kristof. He notes that Nisbett “strongly advocates intensive early childhood education because of its proven ability to raise I.Q. and improve long-term outcomes.” The Milwaukee Project showed that in a randomly assigned study, “By age 5, the children in the program averaged an I.Q. of 110, compared with 83 for children in the control group. Even years later in adolescence, those children were still 10 points ahead in I.Q.”
Nisbett also pushes a simple idea: “tell junior-high-school students that I.Q. is expandable, and that their intelligence is something they can help shape. Students exposed to that idea work harder and get better grades. That’s particularly true of girls and math, apparently because some girls assume that they are genetically disadvantaged at numbers; deprived of an excuse for failure, they excel.”
For more on these types of interventions, see Nisbett’s recent op-ed Education Is All In Your Mind. The one thing I would add is that motivation needs to work hand-in-hand with opportunity. Working harder to no effect, with little sense that one’s effort will lead to a better outcome, is pernicious.
Kristof has addressed education and intelligence in other columns, which I also recommend. He wrote about DC schools and the reform efforts of Michelle Rhee in Education’s Ground Zero. Earlier he argued for education as our number one national priority, and a needed focus for both stimulus money and for making the US globally competitive. And in Raising the World’s IQ he discussed the environmental side of generating change, in this case the importance of iodized salt. I’d add lead to that as well, which even at low levels is linked to lower IQ scores.