Subject: anonymous cooperation is stable if opting out possible

Volunteering as Red Queen Mechanism for Cooperation in Public Goods Games Christoph Hauert, Silvia De Monte, Josef Hofbauer, and Karl Sigmund Science May 10 2002: 1129-1132.

Volunteering as Red Queen Mechanism for Cooperation in Public Goods Games

Christoph Hauert,12 Silvia De Monte,13 Josef Hofbauer,1 Karl Sigmund14*

The evolution of cooperation among nonrelated individuals is one of

Reciprocal altruism fails to provide a solution if interactions are not repeated often enough or groups are too large. Punishment and reward can be very effective but require that defectors can be

mechanism operating under full anonymity. Optional participation can foil exploiters and overcome the social dilemma. In voluntary public goods interactions, cooperators and defectors will coexist. We show that this result holds under very diverse assumptions on population structure and adaptation mechanisms, leading usually not to an equilibrium but to an unending cycle of adjustments (a Red Queen type of evolution). Thus, voluntary

the fundamental problems in biology and social sciences. traced and identified. Here we present a simple but effective participation offers an escape hatch out of some social traps.

Cooperation can subsist in sizable groups even if interactions are not repeated, defectors remain anonymous, players have no memory, and assortment is purely random.

1 Institute for Mathematics, University of Vienna, Strudlhofgasse 4, A-1090 Vienna, Austria. 2 Department of Zoology, University of British Columbia, 6270 University Boulevard, Vancouver, BC, Canada V6T 1Z4. 3 Department of Physics, Danish Technical University, DK-2800 Kgs. Lyngby, Denmark. 4 International Institute for Applied Systems Analysis (IIASA), A-2361 Laxenburg, Austria. * To whom correspondence should be addressed. E-mail: karl.sigmund@univie.ac.at