Our Research Article does not argue that elements of an evolved social psychology are unimportant, as Baumard et al. suggest. Nor do we believe, as Delton et al. propose, that purely genetically evolved mechanisms, rooted in kinship and reciprocity, are sufficient to account for the massive expansion of cooperation in the past 10 millennia and the diversity of human sociality. We argue that understanding this expansion requires the integration of work on both cultural and genetic evolution.
