title: Phase transitions and volunteering in spatial public goods games.
abstract: We present a simple yet effective mechanism promoting cooperation under full anonymity by allowing for voluntary participation in public goods games. This natural extension leads to "rock-scissors-paper"-type cyclic dominance of the three strategies, cooperate, defect, and loner. In spatial settings with players arranged on a regular lattice, this results in interesting dynamical properties and intriguing spatiotemporal patterns. In particular, variations of the value of the public good leads to transitions between one-, two-, and three-strategy states which either are in the class of directed percolation or show interesting analogies to Ising-type models. Although volunteering is incapable of stabilizing cooperation, it efficiently prevents successful spreading of selfish behavior.
authors.affiliation: Research Institute for Technical Physics and Materials Science, P.O. Box 49, H-1525 Budapest, Hungary.
authors.forename: György
authors.initials: G
authors.lastname: Szabó
authors.forename: Christoph
authors.initials: C
authors.lastname: Hauert
mesh_terms: D004467:Economics; D008962:Models, Theoretical; D012919:Social Behavior; D014838:Volunteers