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Brothers in Arms: Cooperation in Defence

Author

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  • David Hugh-Jones
  • Ro'i Zultan

Abstract

In experiments, people behave more cooperatively when they are aware of an external threat, while in the field, we observe surprisingly high levels of cooperation and altruism within groups in conflict situations such as civil wars. We provide an explanation for these phenomena. We introduce a model in which different groups vary in their willingness to help each other against external attackers. Attackers infer the cooperativeness of a group from its members' behaviour under attack, and may be deterred by a group which bands together against an initial attack. Then, even self-interested individuals may behave cooperatively when threatened, so as to mimic more cooperative groups. By doing so, they drive away attackers and increase their own future security. We argue that a group's reputation is a public good with a natural weakest-link structure. We test the implications of our model in a laboratory experiment.

Suggested Citation

  • David Hugh-Jones & Ro'i Zultan, 2010. "Brothers in Arms: Cooperation in Defence," Jena Economic Research Papers 2010-064, Friedrich-Schiller-University Jena.
  • Handle: RePEc:jrp:jrpwrp:2010-064
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    References listed on IDEAS

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    Cited by:

    1. Frans van Winden, 2012. "Affective Social Ties - Missink Link in Governance Theory," Rationality, Markets and Morals, Frankfurt School Verlag, Frankfurt School of Finance & Management, vol. 3(57), October.

    More about this item

    Keywords

    cooperation; conflict; defence; signaling;

    JEL classification:

    • C73 - Mathematical and Quantitative Methods - - Game Theory and Bargaining Theory - - - Stochastic and Dynamic Games; Evolutionary Games
    • C92 - Mathematical and Quantitative Methods - - Design of Experiments - - - Laboratory, Group Behavior
    • D74 - Microeconomics - - Analysis of Collective Decision-Making - - - Conflict; Conflict Resolution; Alliances; Revolutions

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