Information, variance and cooperation: minimal models

Abstract

There is increasing awareness that inter-individual variation can affect the propensity of individuals to cooperate. Here we formally examine the role of variation in the context of animal conflict, assuming that individuals vary in resource holding potential (RHP) and are capable of adopting strategies (Hawk if strong, Dove if weak) based on this trait. Our models allow winners and/or losers of contests to pay costs of fighting that vary with the difference in RHP between contestants. In contrast to earlier studies, we identify a broad range of conditions under which increasing variation in RHP serves to reduce rather than to enhance the proportion of conflicts resolved without fighting. Moreover, we show that in many cases ignorance of one’s RHP can lead to a higher tendency for individuals to cooperate than awareness of one’s RHP. Equally counterintuitively, precluding fights between individuals strong enough to want to fight and individuals not strong enough to want to fight decreases the overall extent to which conflicts are settled without conflict, by enhancing the incentive to act like a Hawk. Collectively, our results indicate that the effect of RHP variation on the tendency of individuals to resolve conflicts without fighting is more subtle than previously anticipated.