Contingent movement and cooperation evolve under generalized reciprocity

Abstract

How cooperation and altruism among non-relatives can persist in the face of cheating remains a key puzzle in evolutionary biology. Although mechanisms such as direct and indirect reciprocity and limited movement have been put forward to explain such cooperation, they cannot explain cooperation among unfamiliar, highly mobile individuals. Here we show that cooperation may be evolutionarily stable if decisions taken to cooperate and to change group membership are both dependent on anonymous social experience (generalized reciprocity). We find that a win-stay, lose-shift rule (where shifting is either moving away from the group or changing tactics within the group after receiving defection) evolves in evolutionary simulations when group leaving is moderately costly (i.e. the current payoff to being alone is low, but still higher than that in a mutually defecting group, and new groups are rarely encountered). This leads to the establishment of widespread cooperation in the population. If the costs of group leaving are reduced, a similar group-leaving rule evolves in association with cooperation in pairs and exploitation of larger anonymous groups. We emphasize that mechanisms of assortment within populations are often behavioural decisions and should not be considered independently of the evolution of cooperation.

Does mobility decrease cooperation?

“…By letting both mobility and cooperative traits evolve together, Koella [32] (see also Ref. [20,33,53]) obtained low dispersive altruists and highly dispersive egoists which enhanced the stability of local clusters. Again, there was no explicit diffusive behavior as mobility was introduced by generating offspring within a given dispersal range.…”

Evolutionary Prisoner’s Dilemma Game in Flocks

“…The cost of mobility could affect the origin of altruism, while the rise of altruism cost would lead to an evolutionary reduction of mobility [19]. And with a win-stay, lose-shift rule cooperation would be evolutionary stable under generalized reciprocity [20]. Further, in agent-based models mobility of individuals can be involved explicitly as the movement of agents.…”

On the further integration of cooperative breeding and cooperation theory

“…Generalized reciprocity results when B helps C because A helped B independently of the identity of individuals (Hamilton and Taborsky, 2005a;Pfeiffer et al, 2005;Rutte and Taborsky, 2007). There is evidence for generalized reciprocity in humans (Yamagishi and Cook, 1993) and rats (Rutte and Taborsky, 2007).…”

“…There is evidence for generalized reciprocity in humans (Yamagishi and Cook, 1993) and rats (Rutte and Taborsky, 2007). It is related to kin selection because, ultimately, both rely on positive assortment of co-operators (Hamilton, 1975;Hamilton and Taborsky, 2005a;Lehmann and Keller, 2006). Both Skubic (2007) and Taborsky (2007) criticized our omission of generalized reciprocity, but unfortunately neither of both commenters discussed how generalized reciprocity could be acting in cooperative breeders.…”