Early humans domesticated themselves, new genetic evidence suggests

It seems there was a tipping point in human evolution where trade and negotiation grew more beneficial to a given tribe (or group of tribes) than attempting to kill all your competition through war. You could get the best arrowhead stones without hiking hundreds of miles, for example. Art and culture relatively suddenly spiked roughly around 50,000 years ago. Neanderthals arguably had a bigger brain. It's not raw intelligence that set us apart, it was leveraging social networks (the analog type).

A few speculative hypotheses for consideration:

1. Ultraviolence: An extremely violent cultural ritual developed that resulted in a much higher rate of fatality for participants. Then, the genetically predisposed to warlike behaviour would be killed off systematically before breeding. This would have the additional effect of clearing outgroup humanoids in the area.

2. Gender Roles: Male sexual selection for females focused on cooperation attributes -- or aesthetic attributes like the facial ones associated in the paper.

3. Cooperative warfare: Cooperative traits allowed for better outgroup warfare

4. BBQ Theory of Human Evolution: Cooperative traits allowed for better big-game hunting. Mammoth barbecues attracted mating prospects from large areas, resulting in the rapid sexual-selection effect of amplifying cooperative genes

"Society tames the wolf into a dog. And man is the most domesticated animal of all." -- Friedrich Nietzsche