The Shared Reward Dilemma

Abstract

One of the most direct human mechanisms of promoting cooperation is rewarding it. We study the effect of sharing a reward among cooperators in the most stringent form of social dilemma, namely the Prisoner's Dilemma. Specifically, for a group of players that collect payoffs by playing a pairwise Prisoner's Dilemma game with their partners, we consider an external entity that distributes a fixed reward equally among all cooperators. Thus, individuals confront a new dilemma: on the one hand, they may be inclined to choose the shared reward despite the possibility of being exploited by defectors; on the other hand, if too many players do that, cooperators will obtain a poor reward and defectors will outperform them. By appropriately tuning the amount to be shared a vast variety of scenarios arises, including traditional ones in the study of cooperation as well as more complex situations where unexpected behavior can occur. We provide a complete classification of the equilibria of the $n$-player game as well as of its evolutionary dynamics.

Major rewriting, new appendix, new figures

References in corpus (2)

• Information diffusion epidemics in social networks
• Cooperation and the Emergence of Role Differentiation in the Dynamics of Social Networks

Cited by in corpus (6)

• Aspiring to the fittest and promotion of cooperation in the prisoner's dilemma game
• Alliance formation with exclusion in the spatial public goods game
• Benefits of tolerance in public goods games
• Optimal distribution of incentives for public cooperation in heterogeneous interaction environments
• Shared rewarding overcomes defection traps in generalized volunteer's dilemmas
• Gains from switching and evolutionary stability in multi-player matrix games