title: Why people punish defectors. Weak conformist transmission can stabilize costly enforcement of norms in cooperative dilemmas.
abstract: In this paper, we present a cultural evolutionary model in which norms for cooperation and punishment are acquired via two cognitive mechanisms: (1) payoff-biased transmission-a tendency to copy the most successful individual; and (2) conformist transmission-a tendency to copy the most frequent behavior in the population. We first show that if a finite number of punishment stages is permitted (e.g. two stages of punishment occur if some individuals punish people who fail to punish non-cooperators), then an arbitrarily small amount of conformist transmission will stabilize cooperative behavior by stabilizing punishment at some n -th stage. We then explain how, once cooperation is stabilized in one group, it may spread through a multi-group population via cultural group selection. Finally, once cooperation is prevalent, we show how prosocial genes favoring cooperation and punishment may invade in the wake of cultural group selection.
authors.affiliation: University of Michigan, 701 Tappan Road, D3276, Ann Arbor, MI 48109-1234, USA. henrich@umich.edu
authors.forename: J
authors.initials: J
authors.lastname: Henrich
authors.forename: R
authors.initials: R
authors.lastname: Boyd
mesh_terms: D003299:Cooperative Behavior; D003468:Cultural Evolution; D006801:Humans; D008960:Models, Psychological; D011678:Punishment; D012925:Social Conformity