36 Pages Posted: 23 Jul 2011
Date Written: September 22, 2010
In experiments, people behave more cooperatively when they are aware of an external threat, while in the field, we observe surprisingly high levels of within - group cooperation 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’ behavior under attack, and may be deterred by a group that bands together against an initial attack. Then, even self-interested individuals may defend each other 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 extend the model from cooperation in defence to cooperative and altruistic behavior in general.
Keywords: cooperation, conflict, signaling, groups
JEL Classification: C90, D74
Suggested Citation: Suggested Citation