As a Christian I cannot hold racist views (Gal 3:28). I believe the major factor that arrested development in some areas, was the culture which developed.
Some people looked beyond the tribalism pattern, and when they branched out, they started inventing, trying new things and experimenting with new processes.
One group that seems very tribal, is the Somalians. While I have heard that the average IQ for Somalians is about 70, the best source i can find on the web, says about 90..
While rating low on the list of nations, they don't appear to be at the idiot stage.
https://brght.org/iq/country/p/6/ ..But then, their brightest and best do not come near others..
https://brght.org/iq/country/somalia. Surely, if one were to take the top IQs from say, the UK, US, Japan, China or Russia...just to mention a few, they would likely be hovering around the 200 mark..
Of course, just because somebody hails from Somalia, doesn't mean he/she is not intelligent..butv just that the AVERAGE is below others.
Just my $.02..take it or trash it !