Costly signaling and cooperation

We propose an explanation of cooperation among unrelated members of a socia l group in which cooperation evolves because it constitutes an honest signa l of the member's quality as a mate, coalition partner or competitor, and t herefore results in advantageous alliances for those signaling in this mann er. Our model is framed as a multi-player public goods game that involves n o repeated or assortative interactions, so that non-cooperation would be a dominant strategy if there were no signaling benefits. We show that honest signaling of underlying quality by providing a public good to group members can be evolutionarily stable, and can proliferate in a population in which it is initially rare, provided that certain plausible conditions hold, inc luding a link between group-beneficial signaling and underlying qualities o f the signaler that would be of benefit to a potential mate or alliance par tner. Our model applies to a range of cooperative interactions, including u nconditionally sharing individually consumable resources, participating in group raiding or defense, and punishing free-riding or other violations of social norms. (C) 2001 Academic Press.