How War Shaped Human Evolution - David Geary

The gist

1. Geary says around 5,000 to 7,000 years ago most male lineages vanished, leaving 17 female ancestors per male, which he attributes to organized male violence.
2. He says reproductive skew among hunter-gatherer men is about three times higher than among women, rising to roughly 100-fold in early empires.
3. Geary argues war was the main driver of civilization, with large-scale cooperation among strangers emerging mainly to compete against other groups.
4. He says humans' expanded default mode and frontal parietal brain networks let us imagine higher-status futures, then plan how to close the gap.
5. Geary's advice: status anxiety evolved when low status meant higher death risk, so today you can relax about keeping up, debt spending, and kids' competitions.