This book was recommended by one of the economist blogs that I frequent. The author is a cognitive psychologist who bristles at the concept that 75% to 80% of intelligence is inherited. For all of the faults of the book, he gives very good data against this. The numerous problems in the book include:
- Reliance on IQ tests. Yes, Dr. Nisbett is very clear that IQ tests aren’t really numerical intelligence scores, though since they do track with individual’s incomes and perceptions of how smart another person is, (to say nothing of the fact there is no alternative) they are used here whilly nilly.
- In the second and third chapters, he closely tracks the data. He shows where the 75% to 80% figure comes from (separated identical twins) and why the data is wrong (selection bias of adopting families). This is the best part of the book.
- Unfortunately to flesh this to a book-sized document, he continues with three chapters of racial bias/statistics: IQ and Black Americans, IQ and Asian Americans, IQ and European Jews living in the US. None of these chapters hone closely to the numerical data, and are instead a patchwork of anecdotes and unsupportable conclusions (Asians are better because of their Confucian background, etc.). I’d like to applaud him for at least broaching this subject, but I think he steers too far away from hard data for it to be useful. (Personally, I’m with Jared Diamond on this – there is almost certainly no major racial difference in intelligence or, if there is, the New Guinea Highlanders are way more likely to be the smarter than educated Europeans or Americans – see Guns, Germs and Steel or The Third Chimpanzee.)
I’d hoped for a more closely defended book, though the first three chapters are really quite good. A moderate recommendation from me at best. I can boil it down to a simple phrase for you: “Intelligence (as defined by IQ testing) is somewhat hereditary, but not to a level higher than 50% of the final attained score. Health (prenatal, perinatal, and juvenile), education, home environment, extended environment and the like account for the other parts. Heredity may be much less than 50% of the factor involved.”
The reason I’m blogging this here (I don’t normally comment on mediocre books that I read, there are too many of them) is that the author discussed home environments of high-IQ families vs. medium-IQ families. He mentioned that not only do high-IQ families read to their children, but they also participate in discussions. Hmm.
I normally just read to the kids. I make a big show of it – lots of voices, making myself quiet or very loud, jumping when there is a lot of action, etc. But I never really talked much about the books afterwards.
Two nights ago, I was reading the Cat in the Hat to all three. Afterward, I asked if the Cat was a good person or a bad person. That was the only question that I had to ask. It’s like they’d been waiting for all these years for a chance to talk about the Cat in the Hat, but hadn’t had a chance to do it.
They went on for fifteen minutes about characters, who was bad, who was good, what they would or wouldn’t do. You couldn’t stop them. And I didn’t want to. It was a very educational moment. For me.