They do in some of the handful of transracial adoption studies, and don't in others. Rushton and Jensen et al hype the Minnesota study, because it's the one that supports their case, and note data quality problems with the other studies. Nisbett and Flynn do the reverse. But very little work is done in this area (yes, because of PC issues with funding bodies), so the data is still too thin to be very confident either way.

Agreed. More data would be nice.

I am open to a different explanation, it's just that the genetic one seems most compatible with what I do know at this time.

Seeing a prosperous and competent country arising out of Africa would surely be nice. I would prefer living in a universe like that. It's just that I don't see it happening - regardless of the aid - at this time.