Do you still have the book at hand? I looked it up the last time there was a big thread about this on HN. Pinker bases most of that chapter on the work of Eric Turkheimer, as his bibliographic references should show. And Eric Turkheimer has substantially revised his opinion about what heritability studies mean after continuing his research and thinking about the data more. I'll recommend here two articles from Turkheimer's faculty web page

http://people.virginia.edu/~ent3c/vita1_turkheimer.htm

that more readers of Pinker's book ought to know about, to bring their understanding of human behavioral genetics up to date.

http://people.virginia.edu/~ent3c/papers2/Articles%20for%20O...

http://people.virginia.edu/~ent3c/papers2/Articles%20for%20O...