Are inter-demic selection models of the evolution of human altruism empirically plausible?

Samuel Bowles - Santa Fe Institute and University of Siena

Abstract:
Multi-level selection on genetically transmitted altruistic traits is a weak evolutionary force except where extraordinary conditions support significant
genetic differences between groups or enhance the benefits of altruism relative to the costs. Did early Homo sapiens sapiens live under these extraordinary conditions?
Distinctive human social practices and institutions may have created a culturally transmitted niche allowing the proliferation of a genetic predisposition to altruism toward non-kin. Included are the sharing of valued resources within groups, frequent intergroup competition for survival, and the positive assortment that arises when groups that have become too large for effective governance fission. These distinctive aspects of human behavior and social structure presuppose advanced cognitive and linguistic capacities and a process of cultural learning, perhaps accounting for the relative absence
of altruism toward non-kin in most other animals. A model of cultural niche construction clarifies how this process might have worked, and a review of the
available empirical evidence suggests that it may apply to some human ancestral groups during the late Pleistocene and early Holocene.