Relatively large decreases in racial gaps over a decade don’t increase my confidence in a global genetic hypothesis. Below are the dutch CITO gaps (SDs = 10) as reported in Gijsberts, et al., 2012. The CITO is given by 85% of Dutch primary schools to age ~12 students; the sample sizes are large. Bartels et al. reports a 0.63 age 12 correlation between CITO and IQ and a narrow heritability of 0.60. Lynn (2006; 2008) considered the test to be a sufficiently good enough measure of g to include it in his discussions of race differences (see: Lynn, 2006; Lynn, 2008).
Ignore the White-Antillian gap. As Suzanne Model has shown in her exhaustive analysis of the performance of Black Caribbean emigrants to the US, UK, Canada, and the Netherlands, the parents of these kids are fairly selected. Black West Indian emigrants perform approximately the same in these diverse places, suggesting that they are equally selected. In the UK and the US, circa 2010, 2nd generation Black West Indian children/adolescents performed, on tests of mental ability, about a half of a standard deviation below 2nd and 3rd generation Whites. So we might not be surprised that, as of 2008, West Indian Blacks perform only 0.75 SD below Dutch Whites.
Focus instead on the Surinamese-Dutch gap. The gap from 1994 to 1997 is consistent with the 2nd generation IQ gap reported by te Nijenhuis et al. (2004), so this can be taken as a good estimate of the overall IQ gap. Over 2/5ths of Surinamese emigrated to the Netherlands. They can’t possibly be very selected. For reference, here are the rates of emigration by educational attainment as presented by Docquier and Marfouk (2005):
As can be seen by looking at Rate of Emigration by Education, approximately 41% of the emigrants were low skilled and 50% were high skilled. The difference amounts to approximately 0.25 SD deviations. If one compares the number of working age residents by education to working age emigrants to the OECD by education, assuming low, medium, and high skill represent -1 SD, +0 SD, and +1 SD standardized deviations, respectively, above the mean, one arrives at a similar standardized educational difference. Assuming that the correlation between education and general intelligence is the same in Suriname as it is in the West, approximately 0.6, the selection for general intelligence on the account of education could only be 0.15 SD (0.25 X 0.6). Since there would be regression to the mean, the second generation could only be selected approximately 0.1 SD on the account of their parents’ educational selectivity (0.15 x 0.6). Similar analyses can be done to show that on other accounts, Surinamese emigrants to the Netherlands are not particularly selected for g.
To the extent that a hereditarian hypothesis can be reconciled with the small and continually narrowing gap, it must in terms of population composition. According to the CIA World Fact Book, Surinamese are 37% Indian, 31% Creole (mixed white and black), 15% Javanese, 10% African, and 8% other. According to Lynn (2008 p. 205), this population should have a phenotypic IQ of 85; assuming that the narrow heritability of the various global IQ differences is 50%, as argued by Lynn (2006), the IQ gap should be, at minimal 0.5 SD. The 2008 gap, then, is at the minimal level consistent with Lynn’s genetic hypothesis.
Gijsberts, et al., 2012. Bijlagen Jaarrapport integratie 2011
Lynn, 2006. Differences in Intelligence An Evolutionary Analysis
Lynn, 2008. The Global Bell Curve: Race, IQ, and Inequality Worldwide
te Nijenhuis et al., 2004. Are Cognitive Differences Between Immigrant and Majority Groups Diminishing?
Bartels, et al., 2002. Heritability of Educational Achievement in 12-year-olds and the Overlap with Cognitive Ability