Wisely and slow; they stumble that run fast.
The conflict between individual and group interests is a common element in many social dilemmas. Consider the rate at which an organism consumes shared resources. Prudent use of common resources promotes the longevity or fecundity of the group; however, any individual that exhibits restraint suffers in competition with those using resources rapidly. Rapacity is selectively favored and the displacement of prudent types by their unrestrained contemporaries occurs despite harmful consequences for the group (Maynard Smith, 1964; Williams, 1971). Restraint in the use of common resources is a form of altruism: behavior that is self-sacrificial and prosocial. Like other types of altruistic behavior, restraint faces a fundamental problem of subversion (Dawkins, 1976a; Okasha, 2008). How can restrained types persist in the midst of would-be cheaters—individuals that have a competitive edge because they are unrestrained? In this chapter, we address this question directly by outlining ecological conditions sufficient to favor the evolution of restraint.
One ingredient found in most explanations for the evolution of altruism, and thus relevant to the evolution of restraint, is positive assortment. Altruism stands a better chance when altruistic individuals disproportionately help those possessing the genes for altruism (Hamilton, 1975; Queller, 1992b; Pepper and Smuts, 2002; Fletcher and Doebeli, 2009; Godfrey-Smith and Kerr, 2009). One of the most obvious ways to achieve positive assortment is through interactions between genetic relatives (Hamilton, 1964a). In such a case, altruistic individuals disproportionately experience beneficial social environments (engineered by their kin), whereas selfish individuals tend to face a milieu lacking prosocial behavior (because their kin tend to be less altruistic). Interaction with kin can occur actively through the choice of relatives as social contacts or passively through the interaction with neighbors in a habitat with limited dispersal. There is now a large body of literature on the effect of active and passive assortment on the evolution of altruism (Matessi and Jayakar, 1976; Eshel and Cavalli-Sforza, 1982; Toro and Silio, 1986; Wilson et al., 1992; Queller, 1994; Pepper and Smuts, 2002; Lehmann and Keller, 2006; Pepper, 2007; Rankin and Taborsky, 2009). At a fundamental level, this research focuses on the distribution of interactions among altruistic and selfish individuals. However, in many systems, these individuals are also interacting with other members of their community (competing species, predators, prey, mutualists, etc.). It is less