Employing the same methodology used to estimate state average IQs, I’ve been breaking the results down by race. Black estimates by state follow (those not listed had too small an NAEP test-taking contingent to use with any statistical certainty):

1) Washington — 94.5

2) Delaware — 93.9

3) Massachusetts — 93.6

3) Virginia — 93.6

5) Alaska — 93.5

6) New Jersey — 92.9

7) Colorado — 92.9

8) South Carolina — 92.5

9) New Mexico — 92.3

10) Kentucky — 92.2

11) Texas — 92.2

12) New York — 92.1

13) Oregon — 92.0

14) Arizona — 91.9

15) North Carolina — 91.5

16) West Virginia — 91.5

17) Georgia — 91.3

18) Iowa — 91.3

18) Kansas — 91.3

20) Maryland — 91.2

21) Ohio — 91.1

22) Michigan — 91.1

23) Conneticut — 90.6

24) Indiana — 90.4

25) Pennsylvania — 90.4

26) Missouri — 90.4

27) Rhode Island — 90.2

28) Louisiana — 90.1

29) Minnesota — 90.0

30) Illinois — 89.8

30) Oklahoma — 89.8

32) California — 89.7

33) Florida — 89.6

34) Wisconsin — 89.5

35) Tennessee — 89.3

36) Nebraska — 89.0

37) Nevada — 88.7

38) DC — 88.6

39) Mississippi — 88.5

40) Arkansas — 88.0

41) Alabama — 87.8

The relatively high scores jump out immediately to those who are familiar with the historical results of IQ testing by race. Adjusted for population, the average IQ estimate for black Americans comes to just under 91. Traditionally, African Americans 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. Lynn marshalls lots of evidence showing that racial ‘hybrids’ tend toward IQs that are an average of the two groups their parents represent. The offspring of one black and one white parent represent almost 3% of American births today, compared to about 2.3% in 1995 and around 1.3% in 1980. 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). But taking a net 1.7% ‘blending’ and assuming a 15 point gap would only be expected to narrow the gap by a quarter of one point.

Relatedly, states with lighter skinned blacks (those with more white ancestry in the northern states especially) tend to achieve higher test score results, although the results aren’t that pronounced. Deep-south South Carolina certainly bucks the trend, probably due to the number of black military families at Fort Jackson, where most army personnel are initially trained.

– I built the formula for the estimates using 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 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 Steve Sailer’s tentative assertion and the GNXP graph supporting it 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.

(Human biodiversity2)