WBR: Intelligence and How to Get It
As promised, here's a review of Richard Nisbett's Intelligence and How to Get It: Why Schools and Cultures Count. it's the book that Nicholas Kristof's column a couple of weeks ago was based on. The book jacket describes this book as "the authoritative anti-Bell Curve" and indeed, much of the book is a full-out attack on the claim that intelligence is primarily determined by genetics and that any attempts to improve outcomes for members of disadvantaged groups are doomed.
To be honest, the "how to get it" part was the least interesting part of the book for me, because it covered ground that I already know about — Perry Preschool, KIPP, Carol Dweck's work on the "mindset" that effort matters more than inherent ability. That said, Nisbett does a good job of writing about these issues in a non-technical manner, and I'm hopeful that he will influence public opinion.
The "intelligence" part of the book was far more interesting, because Nisbett is implicitly arguing with both the strong hereditarians who believe that intelligence is overwhelmingly genetic and that environment (including parenting) doesn't matter much, and with the liberals who aren't sure exactly what is meant by "intelligence," and are pretty skeptical that intelligence tests are picking up underlying ability rather than leaning. The first two chapters (and a more technical appendix) are aimed squarely at these issues, and should be mandatory reading for anyone who wants to talk about intelligence.
Nisbett argues that the high estimates for the genetic component of intelligence are overwhelmingly based on twin studies, and especially adoptive studies, and these don't haver nearly as much variation in environments as there exists between families overall. He also notes that overall IQ levels have risen steadily over time, far too quickly to be accounted for by natural selection (if you look at the raw scores, rather than the normed ones which are forced to have a constant mean of 100). Addressing the question of racial differences in IQ specifically, he points out that the black-white gap has also decreased significantly in the past decades, and that African-Americans with a higher percentage of European genes do not have higher IQs than African-Americans with fewer European genes.
I'm going to end this review where Nisbett begins the book, on the question of what is intelligence. Even after reading the book, I find it hard to define. Nisbett is clear that he believes that schooling does increase intelligence, and that scores on even the most abstract and supposedly culture-free components of the IQ test (such as the Raven progressive matrices*) improve markedly with practice. So he doesn't agree with the opening quote from Cyril Burt that intelligence is "inborn, all-around intellectual ability.. inherited, not due to teaching or training… uninfluenced by industry or zeal." But he also thinks it's a real characteristic, distinct from specific knowledge of a subject. In some ways, he almost seems to define intelligence as that which is measured by IQ tests, which is a strong predictor of academic and career sucess although not the only factor in either (with effort, emotional skills, self-discipline, and motivation being the strongest non-intelligence factors in these).
* For what it's worth, I would have chosen a different answer than the "correct" one on the sample problem given in the book, and still think that my answer is equally plausible.