title: Cooperation: close friends and common enemies.
abstract: The Prisoner's dilemma game has been a key conceptual tool for analyzing social behavior for over 50 years. A recent study shows how the spatial scale of competition in this game critically determines when cooperation can emerge.
authors.affiliation: Behavioural Ecology Research Group, Department of Biosciences, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada. crespi@sfu.ca
authors.forename: Bernard
authors.initials: B
authors.lastname: Crespi
mesh_terms: D003163:Competitive Behavior; D003299:Cooperative Behavior; D005716:Game Theory; D006801:Humans; D012201:Reward