I dispense with the tradition of color-coding states in the table based on how their populations under consideration voted, for reasons made clear here:
|1. New Jersey||94.7|
|7. North Dakota||93.1|
|10. South Dakota||92.1|
|11. North Carolina||91.5|
|12. West Virginia||91.5|
|20. New York||90.4|
|22. Rhode Island||90.1|
|28. South Carolina||89.1|
|36. District of Columbia||88.3|
|37. New Mexico||88.3|
A map of the same. The darker a state's shading, the higher its black IQ. Yellow indicates insufficient data:
Racial relations in the US military are generally regarded as being better than they are in the civilian world. This is potentially an important reason why that is the case. Hawaii's strong showing is more evidence of just how authentically black Barack Obama is!
The relatively high scores will jump out immediately to those who are familiar with the history of differences in results on IQ tests by race. The estimated national average IQ estimate for black Americans using the methodology described above is 90.1. Traditionally, US blacks have consistently scored around 85, and the gap between whites and blacks has held tenaciously at one standard deviation, so these estimates appear rather high. A few possibilities as to why:
- The black/white IQ gap may be narrowing. Flynn and Dickens argue that blacks have gained five or six points on whites over the last three decades, presumably spurred in part by better access to nutrition and healthcare. If accurate, that would put contemporary average African American IQ at 90 or 91, just as my estimates did.
- The rate of interracial marriage and procreation has increased over time. Richard Lynn marshals a good deal of evidence showing that racial 'hybrids' tend toward IQs that are an average of the two groups their parents represent. This should work to attenuate the gap by slightly lowering average white IQ and raising average black IQ a bit (the latter should rise more than the former falls due to sheer size).
- I built the formula for the estimates using Richard Lynn's data on international academic and IQ test results, so my equation is linear. Although Lynn believes that adjusting for attenuation yields a correlation between test scores and IQ of 1 (a perfect relationship), I'm inclined to assume that the correlations for IQ and math (.87) and IQ and science (.81), even adjusted for attenuation, are still not perfect. And because my formula is linear, moving further out from the averages if anything underestimates the magnitude of the true deviation. So depending on the true strength of the relationship, the estimates might be inflated by a couple of points (although I think this would only be on the order of a point or two).
- Differing rates of truancy by race may be artificially giving blacks a boost relative to whites. Assuming that children frequently absent from school generally come from more chaotic, less endowed households, it follows that students who are the least likely to show up on test day are among the poorest performers. And the absentee rate for black children (24%), defined as missing an average of three or more days per month, is greater than the rate for white striplings (19%).
- According to the late Philip Rushton, black adolescents develop faster than white adolescents (who in turn develop faster than Asians). Consequently, young blacks achieve greater parity with their white counterparts than they do as both groups age. Indeed, very early on black children may be more intelligent than whites and Asians due to relatively accelerated physical development. This meshes with the tentative assertion that the gap may have narrowed among children but doesn't appear to be shrinking among adults. To the extent that differing development levels affect average scores by race, IQ tests based on an average white IQ of 100 given to children will tend to underestimate the eventual cognitive capacity of Asians and overestimate it for blacks.
Parenthetically, the correlation between a state's white-black IQ gap and its propensity to vote for Romney in 2012 is .47 (p-value = .0013). Unfairly, I can imagine Rush Limbaugh pointing this out as evidence that the Democrats benefit from keeping blacks down!