>>14363614A mix of stuff all feeding into each other
Bipedal stance allowed us to make better use of our hands as grasping tools all the time, so we developed better tool use
Using tools, culminating in harnessing fire, allowed us to become more efficient hunters, feeding ourselves better, teaching our children better, and favorably selecting those with better intellectual abilities that would be able to take best advantage of those teachings and also pass the mdown better, in a feedback loop that made us smarter and our accumulated knowledge greater with each generation
We also have some pretty snazzy natural advantages, we are no sabertooths, but we are one of the best stamina runners in the animal kingdom, we can run anything down to their exhaustion, and we are predisposed to gather and hunt socially (not you and me, we'd have to get off 4chins for that) and those advantages allowed us to get a lot of meat when we were otherwise dumb, unarmed apes
Basically we lucked out into the first steps down the path of self-reinforcing evolution of our intellectual abilities
