Regensburg 2013 – scientific programme
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DY: Fachverband Dynamik und Statistische Physik
DY 15: Evolutionary Game Theory (joint session BP/DY/SOE)
DY 15.4: Talk
Tuesday, March 12, 2013, 15:45–16:00, H37
Banish or vanish? The evolution of cooperation by social exclusion — •Tatsuya Sasaki1,2 and Satoshi Uchida3 — 1International Institute for Applied Systems Analysis, Laxenburg, Austria — 2University of Vienna, Vienna, Austria — 3Rinri Institute, Tokyo, Japan
Fines and exclusion are ubiquitous, yet very different ways of punishing freeriders. In the former, punishers are allowed to fine freeriders at a cost to themselves. It is clearly difficult for only fines to promote cooperation due to this punisher's cost. Less clear is the latter, in which punishers are allowed to exclude freeriders from the common good at a cost to themselves. When does exclusion solve the commons dilemma?
We investigate the replicator dynamics in standard public good games with costly exclusion. Costly exclusion reduces the group size, but not necessarily the group benefit, and thus, the punisher's net payoff may increase through excluding freeriders. We demonstrate how exclusion of freeriders can establish a coercion-based regime. Our results do not require a genetic relationship, repeated interaction, reputation, or group selection. Instead, only a limited number of freeriders are required to prevent the second-order freeriders from eroding the social immune system.