Variation in behaviour promotes cooperation in the Prisoner's Dilemma game

JM McNamara, ZL Barta, AI Houston

Research output: Contribution to journalArticle (Academic Journal)peer-review

160 Citations (Scopus)


The Prisoner's Dilemma game(1-4) is widely used to investigate how cooperation between unrelated individuals can evolve by natural selection. In this game, each player can either 'cooperate' (invest in a common good) or 'defect' (exploit the other's investment). If the opponent cooperates, you get R if you cooperate and T if you defect. If the opponent defects, you get S if you cooperate and P if you defect. Here T > R > 0 and P > S, so that 'defect' is the best response to any action by the opponent. Thus in a single play of the game, each player should defect. In our game, a fixed maximum number of rounds of the Prisoner's Dilemma game is played against the same opponent. A standard argument based on working backwards from the last round(1,5) shows that defection on all rounds is the only stable outcome. In contrast, we show that if extrinsic factors maintain variation in behaviour, high levels of co-operation are stable. Our results highlight the importance of extrinsic variability in determining the outcome of evolutionary games.
Translated title of the contributionVariation in behaviour promotes cooperation in the Prisoner's Dilemma game
Original languageEnglish
Pages (from-to)745 - 748
Number of pages4
Volume428 (6984)
Publication statusPublished - 15 Apr 2004

Bibliographical note

Publisher: Nature Publishing Group


Dive into the research topics of 'Variation in behaviour promotes cooperation in the Prisoner's Dilemma game'. Together they form a unique fingerprint.

Cite this