反響を呼んだ『進化の弟子：ヒトは学んで人になった』からの展開。Sterelny sees human evolution not as hinging on a single key innovation, but as emerging from a positive feedback loop caused by smaller divergences from other great apes, including bipedal locomotion, better causal and social reasoning, reproductive cooperation, and changes in diet and foraging style. He advances this argument in The Pleistocene Social Contract with four key claims about cooperation, culture, and their interaction in human evolution.