>>2498861And this. If you look at the brain of a retarded kid, or a primate, the main difference will be the folding, not size.
But also brain-to-body ratio is important, dolphins have brains that are both larger and more folder.
Then the main and most important aspect, is culture, which is to say, gathered knowledge of hundreds of generations. If you take a human kid from 70k years ago and put it in a modern school, it would be in line with modern humans, possibily a bit less intelligent and stronger physically.
But take a modern kid and put it 70k years ago (or in tribal africa) and it will be functionally retarded by our standards.
