Posted by Jed Lewison on Thu May 31, 2007 at 7:46 AM Pacific

Environment versus genetics in race and intelligence

Over the course of a few days last week and into this weekend, I debated a poster (Chris Chang aka dogofjustice) on Paul Phillips' blog about whether environment or genetics plays a bigger role in determining differences amongst races in performance on things like standardized tests and IQ tests.

If you know me at all, you know I'm firmly in the environmental camp, but reading the full thread on Paul's blog will give you a sense of how deeply entrenched some people are in the genetic/hereditarian camp. It's frustrating to me because it seems so clear that the overwhelming weight of evidence points towards environmental explanations, yet so many people cling to genetic explanations.

One paper that is worth reading is "Testing for Racial Differences in the Mental Ability of Young Children" by Roland Fryer and Steven Levitt. Here is the abstract:

On tests of intelligence, Blacks systematically score worse than Whites. Some have argued that genetic differences across races account for the gap. Using a newly available nationally representative data set that includes a test of mental function for children aged eight to twelve months, we find only minor racial differences in test outcomes (0.06 standard deviation units in the raw data) between Blacks and Whites that disappear with the inclusion of a limited set of controls. Relative to Whites, children of all other races lose ground by age two. We confirm similar patterns in another large, but not nationally representative data set. A calibration exercise demonstrates that the observed patterns are broadly consistent with large racial differences in environmental factors that grow in importance as children age. Our findings are not consistent with the simplest models of large genetic differences across races in intelligence, although we cannot rule out the possibility that intelligence has multiple dimensions and racial differences are present only in those dimensions that emerge later in life.

One other paper that I highly recommend is "Thin Ice: 'Stereotype' Threat and Black College Students" by the Stanford psychologist Claude Steele (brother of Shelby Steele).

One paper that is worth reading is "Testing for Racial Differences in the Mental Ability of Young Children" by Roland Fryer and Steven Levitt. Here is the abstract:

On tests of intelligence, Blacks systematically score worse than Whites. Some have argued that genetic differences across races account for the gap. Using a newly available nationally representative data set that includes a test of mental function for children aged eight to twelve months, we find only minor racial differences in test outcomes (0.06 standard deviation units in the raw data) between Blacks and Whites that disappear with the inclusion of a limited set of controls. Relative to Whites, children of all other races lose ground by age two. We confirm similar patterns in another large, but not nationally representative data set. A calibration exercise demonstrates that the observed patterns are broadly consistent with large racial differences in environmental factors that grow in importance as children age. Our findings are not consistent with the simplest models of large genetic differences across races in intelligence, although we cannot rule out the possibility that intelligence has multiple dimensions and racial differences are present only in those dimensions that emerge later in life.

One other paper that I highly recommend is "Thin Ice: 'Stereotype' Threat and Black College Students" by the Stanford psychologist Claude Steele (brother of Shelby Steele).