Saturday, October 20, 2007

Role of culture in racial differences in IQ

Here's the abstract of a recent paper by Joseph F. Fagan and Cynthia R. Holland [link via -- who else?! -- Cosma Shalizi]:

African-Americans and Whites were asked to solve problems typical of those administered on standard tests of intelligence. Half of the problems were solvable on the basis of information generally available to either race and/or on the basis of information newly learned. Such knowledge did not vary with race. Other problems were only solvable on the basis of specific previous knowledge, knowledge such as that tested on conventional IQ tests. Such specific knowledge did vary with race and was shown to be subject to test bias. Differences in knowledge within a race and differences in knowledge between races were found to have different determinants. Race was unrelated to the g factor. Cultural differences in the provision of information account for racial differences in IQ.


  1. M said...

    re: Cosma Shalizi & the g-factor.

    As Steve Hsu (involved in the Cognitive Genomics Project) has pointed out, anyone who understands factor analysis realises that you can have correlations and a single largest factor even if there are no underlying causal reasons (i.e., it is just an accident). Nonetheless, these models may still be useful.

    Prior to the availability of molecular studies the heritability of type II diabetes was estimated at 0.25 using all those methods. Now molecular studies have identified at least 9 loci involved in the disease. There are other examples in relation to height. So you can’t say that heritability studies, with all their seemingly ridiculous assumptions, are worthless.

    In fact, reading Shalizi closely, you’ll see that he doesn’t think they are either. For instance, he says:

    ***If you put a gun to my head and asked me to guess [whether there are genetic variants that contribute to IQ], and I couldn’t tell what answer you wanted to hear, I’d say that my suspicion is that there are, mostly on the strength of analogy to other areas of biology where we know much more. ***

    Also, in his article on g he seems to accept in the footnotes that intelligence or cognitive ability, as operationally defined by psychologists, is important for economic development.

    His criticism of g is also met here. Still just 1 g: Consistent results from five test batteries Johnson et al
    Intelligence Volume 36, Issue 1, January–February 2008, Pages 81–95