In 1976, a study was published by prolific American psychologists Dr. Sandra Scarr and Dr. Richard A. Weinberg, the first female full professor in psychology at Yale University and a developmental psychologist at the University of Minnesota, respectively. It was titled, IQ Test Performance of Black Children Adopted by White Families, wherein, “to separate genetic factors from rearing conditions, 130 black/interracial children adopted by advantaged white families were studied.” 

The goal of the study was to address the epidemic of “the poor performance of black children on IQ tests and in school” by surveying the intelligence of adopted black children raised by middle-class white families, contrasted with the intelligence of non-adopted black children raised by black families.

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The results of the study, which was conveyed in 1975, would not be known until 1992, when the two professional psychologists published, a follow-up, titled, The Minnesota Transracial Adoption Study: A follow-up of IQ test performance at adolescence (read the article here). The results found that non-adopted children with two white biological parents score higher on IQ tests than their adopted, non-white counterparts. The following chart depicts the data discovered by the psychologists: 

Evidently, children with two biological black parents who were adopted by middle-class white families scored nearly 25 points lower on IQ tests at the age of 17 than their non-adopted white counterparts. 

However, the above data did not account for the Flynn effect, which was not well-documented until the early 1990s. In the year 2000, steps were taken to correct the above chart, resulting in the following corrected data: 

The drastic difference in IQ between the two races, black and white, is the most intriguing, as there has never been an infinitive declaration on how to interpret this staggering figure. Because the black children possessed discernable African ancestry, it has been argued that the results above reflect a hereditarian worldview, whereby one’s genetic makeup can be invoked to explain traits and personality, including intelligence and nature. On the  other hand, the psychologists admit that this is not the only possible interpretation, because,

“transracial adoption studies only control for family environment, not social environment. For example, children who are socially identified as black may still be subject to racial discrimination despite being raised by white parents.” 

However, it is possible that hereditarianism is not mutually exclusive from social environment, and in fact, they may be one in the same. In South Africa, the national IQ has been recorded to be 77 as of 2006, and this can be attributed at least partially to the lack of educational development achieved in the Sub-Saharan world. There existed virtually no educational, administrative, or civil institutions present in Southern Africa until European colonialism in the late 19th and early 20th centuries. With the advent of the white man and the newfound privilege of mass migration into European countries, South African peoples have only recently been capable of utilizing tools such as the university.

However, there has been absolutely no credible evidence that argues that the educational gap between races is closing in the United States. Despite the massive quantities of state and federal regulations enforced on educational institutions to chip away at the racial achievement gap, the expanse remains as wide as ever, and in some cases, has widened. As eloquently states, “despite significant increases in education spending at all levels and the federal government’s ever-increasing role in education, national academic achievement has remained relatively flat, graduation rates have stagnated around 70 percent, and racial disparities persist.” 

This, coupled with the natural differences demonstrable by surveying native African populations, seems to argue that the disparity in intelligence between black and white Americans is not predominately environmental, but is actually latent in the natural differentiation between populations.