Tuesday, January 26, 2010

Science Vs. Advocacy...

By Professor J. Philippe Rushton

In his book, Intelligence and How to Get It, Richard E. Nisbett, a social psychologist at the University of Michigan, asserts that cultural factors alone are sufficient to explain all the race differences to be observed in IQ and educational achievement.

Nisbett [Email] criticizes the nature + nurture model Arthur Jensen and I presented in 2005 in Psychology, Public Policy, and Law. . [Thirty Years Of Research On Race Differences In Cognitive Ability (PDF)] Nisbett claims the heritability of IQ is lower than assumed, that Blacks have substantially narrowed the gap on Whites, that any remaining differences can be eliminated through educational and social intervention, and that any assertion of a mean IQ of 70 for sub-Saharan Africans is “desperately wrong”.

The dust jacket blurb puts Nisbett’s book in the tradition of Stephen Jay Gould’s Mismeasure of Man (1981, 1996). What is striking, however, is how much ground the egalitarians have given since Gould’s effort to debunk race, genetics, and IQ.

Nisbett concedes that general intelligence exists, that IQ tests predict success at both school and work, that scores are influenced by genes, and that in White populations, genes contribute to social class differences. He even accepts that IQ is related to brain size and that “Blacks are sometimes found to have smaller brains than Whites”. Gould must be spinning in his grave!

Such is the state of expert opinion today that Nisbett simply had to make these concessions lest his book be disqualified as serious scholarship. But while he admits that genes play a role in accounting for within-group differences, he still maintains they play no significant part in between-group differences.

Nisbett acknowledges that measured group differences exist: Jewish (mean IQ = 113), East Asian (107), White (100), South Asian (87), Hispanic (87), African American (85), and sub-Saharan African (70), although he erroneously claims that South Asians score as highly as East Asians. But Nisbett asserts that family pressure for success leads East Asians and Jews to high levels of achievement, while low expectations and a lack of opportunity lead Hispanics and Blacks to much lower levels of achievement.

Jensen and I have provided a long point-counterpoint review of Nisbett’s book in The Open Psychology Journal. [Race and IQ: A Theory-Based Review of the Research in Richard Nisbett’s Intelligence and How to Get It(PDF)] We found much that was admirable and informative in it, such as the cost-benefit survey of the literature on educational interventions and what can be done to increase school performance. But, sadly, we concluded it was mainly a work of advocacy, not scholarship.

Nisbett misrepresents much of the available information using highly selective reviews of the literature. Especially egregious are his many errors of omission. For example, while complaining of unrepresentative samples in a 1991 review paper by Richard Lynn, Nisbett side-stepped the very much larger compilation of data in Lynn and Vanhanen’s 2006 book. Nisbett completely ignores the adoption studies of East Asians, as well as those on brain size showing a genetic contribution to their high achievement.

I’m going to group Nisbett’s flaws under seven heads:

-the rest here