How does David Geary say war shaped human evolution on Modern Wisdom?

David Geary told Chris Williamson that better tools and food, from Homo erectus about 1.8 million years ago onward, grew populations and sharpened competition for resources. Groups pushed into rivals' territory, violence rose, and competing Homo species went extinct. Geary argues this between-group conflict, led by coalitions of related men, drove brain expansion, technology and ever larger cooperative societies.

• Geary says at least eight Homo species existed at one point, and the more shared an area, the likelier some went extinct.
• Modern humans reached Eurasia about 60,000 years ago and displaced the Neanderthals, with some interbreeding and signs of violence.

Source: our own transcription of the episode. The full conversation is on Modern Wisdom (2026-11-05). Read the whole episode summary →

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