It was already fairly obvious that genetics did not play the most significant role in the white-black IQ difference. American blacks, for example have about 1/5 White ancestry, yet score about half-way between African blacks and American whites. If genetics played the most significant role, we would expect American blacks to be closer to African blacks. But, this is not the case: as American blacks enjoy better living conditions than African blacks, they have a correspondingly higher IQ.
Furthermore, it is well-known that American blacks were oppressed in American society even after their liberation, and have only achieved legal equality in the last two generations. Thus, it is not surprising that their IQ level rises. It is also known that blacks still have a deficit when it comes to living in good homes and neighborhoods, being breastfed, attending good schools, and they also have problems finding good jobs because American elites prefer to high cheaper and more docile immigrants, especially from Latin America. Moreover, black culture is unfortunately often opposed to education and scholastic achievement, and favors other avenues of achievement.
Thus, it would seem that American blacks could further reduce the racial IQ gap in the future if progress is made in the above factors. Perhaps a small IQ gap could remain even after full environmental equality is achieved, but it is increasingly clear that any kind of "racial" difference in intelligence is of small scope, especially since American Negroids are already performing as well as some Caucasoid and Mongoloid groups.
From the paper:
The constancy of the black/white IQ gap is a myth. Blacks have gained 5 or 6 IQ points on whites over the last 30 years. Neither changes in the ancestry of those classified as black nor changes in those who identify as black can explain more than a small fraction of this gain. Therefore, environment has been responsible. The last two decades have seen both positive and negative developments: gains in occupational status and school funding have been accompanied by more black preschoolers in single-parent homes and lower income in those homes (Neal, in press). We believe that further black environmental progress would engender further black IQ gains.
Forthcoming: Psychological Science, October 2006
Black Americans Reduce the Racial IQ Gap: Evidence from Standardization Samples
William T. Dickens and James R. Flynn
It is often asserted that blacks have made no IQ gains on whites, despite relative environmental gains, and that this adds credibility to the case that the black/white IQ gap has genetic origins. Until recently, there have been no adequate data to measure black IQ trends. We analyze data from nine standardization samples for four major tests of cognitive ability. These suggest that blacks have gained 5 or 6 IQ points on non-Hispanic whites between 1972 and 2002. Gains have been fairly uniform across the entire range of black cognitive ability.