>>4165793well, one explanation i've heard is because life in africa is so easy you don't need to get smart. mostly because there are no harsh winters in subsaharan africa. so they never evolved a sense of planning. you didn't need to prepare for a harsh winter, so you never needed to think ahead, you never needed to develop agriculture, animal husbandry, you never needed to eat less now, so you have more food later, etc. food was plentiful all the time so without any real challenges, they never needed to get smart to stay alive.
and of course this translates into more than just planning for winter, it affects almost every kind of thinking.
this is a good theory i've heard, although it's not perfect imo and obviously very hard to prove empirically. they could be dumb at a genetic level even, but we can't prove that yet.
desu the reason why isn't all that important, what matters is that there is obviously something wrong with them and that's obvious by the fact that they literally are incapable of building or maintaining a civilized society.