Tuesday, September 01, 2009

Intelligence and Education: Richard Nisbett Says the Evironment Matters

If you're a parent and wonder if you can do something to help your child succeed in the world, the answer is: you usually can. Richard E. Nisbett has written a book called Intelligence and How to Get It: Why Schools and Cultures Count. Nisbett admits that he once leaned more towards the hereditarian view of intelligence but changed his mind as an increasing body of research shows that while some intelligence is inherited, the dominant influence is the environment.

Here's an excerpt from a book review by Jim Holt in The New York Times:
...Nisbett bridles at the hereditarian claim that I.Q. is 75 to 85 percent heritable; the real figure, he thinks, is less than 50 percent. [Hereditarian] estimates come from comparing the I.Q.’s of blood relatives — identical twins, fraternal twins, siblings — growing up in different adoptive families. But there is a snare here. As Nisbett observes, “adoptive families, like Tolstoy’s happy families, are all alike.” Not only are they more affluent than average, they also tend to give children lots of cognitive stimulation. Thus data from them yield erroneously high estimates of I.Q. heritability. (Think: if we all grew up in exactly the same environment, I.Q. differences would appear to be 100 percent genetic.)

Holt gives a reasonably fair review though I wish he had mentioned that there is something of a revolution going on in biology. It seems living organisms, including ourselves, are much more influenced by the environment than we previously thought. Genes are very important but they are not the whole story.

I highly recommend Nisbett's book. Science has had a bias for a hundred years that probably stems from 19th century beliefs that were never properly examined and never properly laid to rest.

One of the results Nisbett talks about is how everyone's I.Q. has been rising for the past 70 years or so. That would hardly make sense unless the environment matters. There are many statistical observations like this that bring into question what I would call the hard hereditarian view. Another one is that the I.Q. gap between blacks and whites grows from kindergarten to the end of high school. And then shrinks over the next four years for those blacks who go to college. As the poets say, "something is obviously going on."

One thing to keep in mind is that attributing things to genes is easy, sometimes too easy. The reality—as we are learning more and more all the time—is always more complex. People do vary but they are far more malleable than many people are willing to admit. All of this is consistent with the latest brain research which shows that the brain is highly adaptable and far more intricate than we realized. Our brain doesn't even finish developing until our late twenties. Even then, our brains keep changing for the rest of our lives. And whether we are six years old or sixty years old we're discovering that the old adage: use or lose it applies to the brain as well. I like that Nisbett takes the trouble to explore some of that complexity.

A preview of Nisbett's book can be found on Google books for those who can't afford it. But it's a book worth buying.



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