Here are the results for the
Minnesota Transracial Adoption Study, mentioned in the APA report:
Adopting parents tested when children were 7 and 17: 120*, 115**
Nonadopted, with two White biological parents: 117*, 109**
Adopted, with two White biological parents: 112*, 106**
Adopted, with one White and one Black biological parent: 109*, 99**
Adopted, with two Black biological parents: 97*, 89**
* Score at IQ test conducted at the age of 7
** Score at IQ test conducted at the age of 17
(The two tests were different and were also differently weighted.)
Thus, the mean IQ for seven-year-old adopted children with two White biological parents was 117 (the tests being conducted in 1975).
By comparison, in the APA report, the mean IQ in the first test (conducted in the late 70s/early 80s on four-year-olds) was 120; in the second test (conducted in the mid-70s on ten-year-olds) it was 112 (for the ‘adequately nourished’ group); in the third test (conducted on Belgian ten-year-olds in the mid-to-late 80s) the mean average was 119.
All in all, it does seem like there is very little difference (117 vs 120, 112 and 119). I find it astonishing that the APA researchers compared the adopted East Asian kids to
average White kids rather than
adopted White kids.