From Audacious Epigone.
The figures are quite heartening, but I think that they are in error. Check them out yourself.
As you can see, the average score for Blacks in the US is 91.
AE goes on to give several reasons why this score is higher than the normal ~85 that we typically see. His first point is that the Black IQ may be increasing. It is, but probably only for Black children. His second point is that intermarriage is increasing. This is true, but there is probably not even mulattoization to account for rising scores. Flynn and Dickens discuss that in one of their papers. The other points he gives are not relevant.
His final point is that Blacks mature more early than Whites. This is most probably the reason for the rising scores, because the scores were done on Black 8th grade 13 year olds.
I do not think it is so true that Blacks mature earlier and therefore Black kids have higher scores. In Africa, both Black kids and adults score ~67, so there is no IQ advantage for Black children.
What I believe is happening in the West is that the super-stimulating environment of the West is jacking up the scores of Black kids. At age 5, Black kids have an IQ of 95. However, as they move into adulthood, it is possible that environmental effects on IQ wear off and genetic effects kick in.
The problem with this is that White kids in the US show no advantage in youth. The White youth IQ is 103 and the White adult IQ is 103.
So why would the environment artificially jack up the scores of Black kids but not White kids? It doesn’t seem to make any sense. If Blacks mature sooner and this is the reason for the higher scores in Black kids versus Black adults, then why doesn’t this effect take place in Africa?
At the end of the day, the elevated scores of Black youths, which have indeed been rising quite a bit in the West, which then crash back down to ~85 in adulthood, must be seen as yet another mystery.