I'm familiar. I believe you're referring to Moore 1986.
(
http://psycnet.apa.org/index.cfm?fa=buy.optionToBuy&id=1986-24139-001)
Black children adopted by middle-class Black families (Mean IQ = 103, N = 17)
Black children adopted by middle-class White families (Mean IQ = 118, N = 9)
Biracial children adopted by middle-class Black families (Mean IQ = 105.7, N = 6)
Biracial children adopted by middle-class White families (Mean IQ = 116.5, N = 14)
"Family socialization and the IQ test performance of traditionally and transracially adopted Black children.
By Moore, Elsie G.
Developmental Psychology, Vol 22(3), May 1986, 317-326.
Abstract
Compared mean IQ test performance and response styles to cognitive demands of the Wechsler Intelligence Scale for Children (WISC) among 23 Black children (aged 7–10 yrs) who had been adopted by middle-class White families (i.e., transracially adopted) and 23 age-matched Black children who had been adopted by middle-class Black families (i.e., traditionally adopted). Findings indicate that while the traditionally adopted Ss received normal IQ scores, transracially adopted Ss showed nearly 1 standard deviation Full-Scale Scoring advantage over them. A multiple analysis of variance (MANOVA) indicated significant differences in the styles of responding to test demands demonstrated by the 2 groups of Ss, which were conceptualized as contributors to the difference in average test score observed between them. Multivariate analysis of the helping behaviors adopted mothers exhibited when helping their children solve a difficult cognitive task revealed significant differences between Black and White mothers, which were conceptualized as culturally determined. White adopted mothers tended to release tension by joking, grinning, and laughing, while Black adoptive mothers more often released tension in less positive ways such as scowling, coughing, and frowning. White adoptive mothers were more likely than Black adoptive mothers to provide positive evaluations of their children's problem solving efforts. It is concluded that the ethnicity of the rearing environment exerts a significant influence on children's styles of responding to standardized intelligence tests and on their test achievement."
-Full text
Also, biracials born to White mothers averaged 9 points higher on the Stanford-Binet than biracials born to Black mothers.
Biracials born to White mothers (Mean IQ = 102, N = 101)
Biracials born to Black mothers (Mean IQ = 93, N = 28)
(
Intellectual development of children from interracial matings: Performance in infancy and at 4 years)