Fig 1. Four ownership institutions governing the retention or transfer of resource items.

Foraged foods tend to be retained by their first possessor, whilst under communal ownership norms items are transferred to others in the group; under command ownership items are transferred to those of higher status, whilst under titled property items are transferred to the holder of legal title. ‘A troop of olive baboons’ photo reprinted under a CC BY license with permission from Amanda Lea, original copyright 2009; cave art after San rock painting in the Drakensberg Mountains; Aztec ritual after an extract from the Codex Magliabechiano; New York Stock Exchange image is in the public domain.