Interesting link
'The 1992 follow-up study found that "social environment maintains a dominant role in determining the average IQ level of black and interracial children"'
And while "Levin[5] and Lynn[6] argued that these findings supported the view that genetics is a determinant of average differences in IQ test performance between races", "other researchers, including Weinberg, Scarr and Waldman, argued that the findings aligned with environmental explanations, noting that the IQ scores of the black children were slightly higher than the national average"
also : "Subsequent developments in genetics research have led to a scholarly consensus that the hypothesis of Levin and Lynn is false."
and
"Scarr and Weinberg (1976) interpreted the results from age 7 suggesting that racial group differences in IQ are inconclusive because of confounding in the study. They noted, however, that the study indicated that cross-racial adoption had a positive effect on black-adopted children. In support of this interpretation, they drew special attention to the finding that the average IQ of "socially classified" black children was greater than that of the U.S. white mean. Follow-up data were collected in 1986, and Weinberg et al. published their findings in 1992, arguing that this follow-up data supported Scarr and Weinberg's original conclusions.
Both Levin[5] and Lynn[6] argued that the data support a hereditarian alternative - that the mean IQ scores and school achievement of each group reflected their degree of Sub-Saharan African ancestry. For all measures, the children with two black parents scored lower than the children with one black and white parent, who in turn scored lower than the adopted children with two white parents. Both omitted discussion of Asian adoptees.
Waldman, Weinberg, and Scarr responded to Levin and Lynn.[16] They noted that the data taken of adoption placement effects can explain the observed differences but that they cannot make that claim firmly because the pre-adoption factors confounded racial ancestry, preventing an unambiguous interpretation of the results. They also note that Asian data fit that hypothesis while being omitted by both Levin and Lynn. They argued that, "contrary to Levin's and Lynn's assertions, results from the Minnesota Transracial Adoption Study provide little or no conclusive evidence for genetic influences underlying racial differences in intelligence and achievement, " and noted that, "We think that it is exceedingly implausible that these differences are either entirely genetically based or entirely environmentally based. The true causes of racial-group differences in IQ, or in any other characteristic, are likely to be too complex to be captured by locating them on a single hereditarianism-environmentalism dimension."[16] "
Yet even Scarr said in 1998 "The results of the transracial adoption study can be used to support either a genetic difference hypothesis or an environmental difference one (because the children have visible African ancestry). We should have been agnostic on the conclusions"
I think you may need to read your cited material a little more objectively. On the whole, your link isn't so black and white on the subject as you suggested and generally does not support either position completely.
(
My Name was saying these words inside your head on, Tue 7 Apr 2026, 12:19,
Reply)
No, I'm aware that the results of that particular study were somewhat ambiguous/inconclusive.
And nurture undoubtedly plays a part in the results, how could it not? But I think the results of this study, plus other studies on the subject indicate that there's a very real plausibility for the hypothesis that there is some genealogical disparity between ethnic groups in regards to intellectual ability, the same way as there are ethnic disparities in regards to things like metabolism or certain health conditions. The brain is still just an organ at the end of the day.
I posted the link mainly to reassure Cummy that discussion on the subject isn't inherently racist unless you treat it as such. The studies themselves are well beyond my remit, I just think it's an interesting topic, and it's nice to be able to have an adult discussion about it without too many people throwing up the racism flag.
(, Tue 7 Apr 2026, 12:39, Reply)