Zones of cooperation in demographic prisoner's dilemma

Abstract

The emergence of cooperation in prisoner's dilemma (PD) games is generally assumed to require repeated play (and strategies such as Tit for Tat, involving memory of previous interactions) or features (“tags”) permitting cooperators and defectors to distinguish one another. In the demographic PD, neither assumption is made: Agents with finite vision move to random sites on a lattice and play a fixed culturally‐inherited zero‐memory strategy of cooperate (C) or defect (D) against neighbors. Agents are indistinguishable to one another—they are “tagless.” Positive payoffs accrue to agents playing C against C, or D against C. Negative payoffs accrue to agents playing C against D, or D against D. Payoffs accumulate. If accumulated payoffs exceed some threshold, agents clone offspring of the same strategy onto neighboring sites and continue play. If accumulated payoffs are negative, agents die and are removed. Spatial zones of cooperation emerge. © 1998 John Wiley & Sons, Inc.

Evolution of Cooperation in the Snowdrift Game With Heterogeneous Population

“…If, additionally, only one strategy is played as in the case of asymptotic stability in Theorems 3 and 4, solubility gap would imply the emergence of a cluster of cooperation and a cluster of defection. This result is similar to one of the cases obtained in [24] where an island of cooperators emerges using an agent-based model but with the game modelled as a prisoner's dilemma and non-tagged individuals. A more precise analysis is left for further research.…”

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“…by Axtell et al [16], Bowles et al [17], Epstein and Axtell [18], and Epstein [19,20] and Tesfatsion [21]. As in their work, our computational results are remarkably sharp and robust.…”