Roland G. Fryer and Steven D. Levitt (2006): Testing for racial differences in the mental ability of young children. Here is the abstract:
On tests of intelligence, Blacks systematically score worse than Whites, whereas Asians frequently outperform 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. The only statistically significant racial difference is that Asian children score slightly worse than those of other races. To the extent that there are any genetically-driven racial differences in intelligence, these gaps must either emerge after the age of one, or operate along dimensions not captured by this early test of mental cognition.
And, here are two interesting paragraphs from the discussion section:
The debate over racial differences in intelligence is among the most divisive in the social sciences. Utilizing a newly available, nationally representative data set with measures of mental function among children before their first birthday, we find little evidence of systematic racial differences. Some substantively small, but statistically significant differences are present in the raw data. Including controls for age, socio-economic status, home environment and prenatal environment largely erase these small differences. A simple calibration exercise suggests that many of the basic facts in the data can be generated from a model in which there are small mean differences in intelligence across races, but large environmental differences across races that become increasingly important as children age. […]
Although damaging to the hypothesis that genetic differences are at the root of racial gaps in intelligence, the results of our analysis do not preclude a possible role for a genetic contribution to racial differences in intelligence for a number of reasons. First, one could reasonably argue that the control variables we include in the regression analysis are themselves partly genetically determined. By controlling for factors such as socio-economic status and birth weight (which systematically differ across races), we may indirectly be parsing out important channels through which genetics are operating. The fact that the raw differences in test performance across races are so small, however, makes this argument largely moot.
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Hat tip: Brad DeLong.