John Holbo’s naming of the two-step of terrific triviality reminded me that this manoeuvre is one of the basic steps in the nature-nurture dance. I looked at
Steven Pinker’s agile performance
a while back.
Anyway, this reminds me of a vaguely related point I’ve been meaning to make for a while. Debate over the relative influence of environment and heredity on intelligence has been going on for at least a century without much change or resolution, or any obvious reduction in the level of vitriol. The only significant new information in the last few decades has been the discovery that average IQ scores have risen substantially over time (the so-called Flynn effect). There has been vigorous debate over whether this effect is real or spurious.
On the other hand, no-one seems particularly exercised about the relative effects of nature and nurture on height, even though the observed patterns seem to be much the same: a fairly high correlation between parents and children, significant class effects, a correlation with wages and a surprisingly strong increasing trend over time.
And much the same things can be said about health, except that the parent-child correlation is specific to particular conditions.
Height, health status and measured intelligence are all positively correlated so it seems as if we should be looking for the same kind of explanation in all cases. This will be left as an exercise for readers (that is, I haven’t got around to working on it myself).
Update The comments do a good job of making my point. There’s plenty of vitriol on the subject of intelligence, but not much new. On the other hand, there’s some interesting, and reasonably civilised, discussion of genetic and environmental determinants of height.