The specific book linked in the grandparent’s post seems to be some silly pop science claim that human intelligence peaked a few thousand years ago when most hu

The specific book linked in the grandparent’s post seems to be some silly pop science claim that human intelligence peaked a few thousand years ago when most humans were hunter gatherers, and subsequently declined. I believe you’re talking about the Flynn effect of rising IQs in the past several decades, which might have actually leveled off recently (or even reversed slightly) in developed countries.