After reading the NYTimes series on class, and my post about it, a reader emailed me to suggest that the discussion of inherited position within a "meritocracy" was ducking the question of genes and IQ. For example, one of the strongest predictors of how well kids do in school is their mother’s level of education. Is this because well-educated mothers read to their kids a lot and use more extensive vocabularies, or because they continued in school because they were good at it, and they passed those genes onto their kids?
It’s a fair question, and the truth is almost certainly a bit of both. A paper by Erik Turkheimer et al. a few years ago found that among very poor families, the environmental conditions were more important than genes in predicting IQ, while among middle- and upper-income families, genetic factors were dominant. The published article is pretty technical, but there’s a nice layperson’s discussion of it and interview with Turkheimer available from Connect for Kids.
This research suggests that there’s a threshold level below which children aren’t able to develop to their full genetic potential. But above that level, what parents do isn’t as critical (at least with regard to IQ) as we often think. As Turkheimer says in the interview:
“In the range where a lot of people spend their time…you know, ‘Should I hang the black and white mobile over my kids’ crib?’ kind of thing, it probably does not matter.”