I think cases of feral/brutally neglected children that grew up without socialization show that IQ development is heavily determined by socialization. https://

I think cases of feral/brutally neglected children that grew up without socialization show that IQ development is heavily determined by socialization. https://en.m.wikipedia.org/wiki/Behavioral_modernity https://en.m.wikipedia.org/wiki/Behavioral_modernity took a ridiculously long time to develop in pre-lingual humans, so it seems like language is a force multiplier for the brain's capacity to do stuff.