Sunday, November 11, 2007

More on women and math: strong evidence for nurture, not nature

Stuart Taylor Jr. wrote an article in the National Journal in 2005 defending Larry Summers's suggestion that innate gender differences in math ability and interest are part of the reason there are so few tenured female professors in science departments at top schools. (It's behind a pay wall; try Google's cached version.)

He includes this in his evidence:
A 1983 study of 40,000 young adolescents by psychologist Camillia Persson Benbow and three colleagues showed "an exponential intensification" of the male-female ratio in the higher ranges of SAT math scores, with 13 times as many boys as girls in the highest range. (That was the 700-to-800 range, on tests normally taken by much older students.) Other studies show boys consistently winning a very disproportionate share of the very highest SAT math scores, and sex differences in mathematical precocity before kindergarten.
Jean Taylor, former president of Women in Mathematics, has a PowerPoint presentation refuting many of the arguments of Stuart Taylor and co. (Google's HTML translation is here.) Among her more eye-catching points is this (my emphasis):
Benbow and Stanley (1980, 1983) (Johns Hopkins) ... male:female ratio among 13-year-olds scoring over 700 on math SAT was 13:1. Huge publicity!

Subsequent Johns Hopkins data, Duke data have showed decreasing ratios; by late 1990’s, down to under 3:1 (2.8:1) (I don’t know of any more recent data). No sign that not still falling.
The story (as always) might be more complicated than that, but at least at first blush, that's a convincing rebuttal. Also, Jean Taylor points out that since the 1940s, the difference between the number of women and men who major in math in college has been shrinking, and that now the numbers are equal. That's strong evidence against innate differences in interest and ability (which I argued in favor of here and here), and strong evidence for the importance of bias and the career effects of pregnancy and child raising.

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