Transitions between homophilic and heterophilic modes of cooperation

TL;DR

This paper uses computer simulations to explore how migration influences the emergence of homophilic and heterophilic cooperation in spatially structured populations, revealing that both cooperation modes can coexist and alternate depending on game parameters.

Contribution

It introduces the role of organismal migration into spatial tag-mediated cooperation models, showing its impact on the evolution of cooperation modes.

Findings

Homophilic cooperation arises over a wide parameter range.

Heterophilic cooperation is stable in well-mixed spatial patterns.

Cooperation modes alternate as temptation to defect increases.

Abstract

Cooperation is ubiquitous in biological and social systems. Previous studies revealed that a preference toward similar appearance promotes cooperation, a phenomenon called tag-mediated cooperation or communitarian cooperation. This effect is enhanced when a spatial structure is incorporated, because space allows agents sharing an identical tag to regroup to form locally cooperative clusters. In spatially distributed settings, one can also consider migration of organisms, which has a potential to further promote evolution of cooperation by facilitating spatial clustering. However, it has not yet been considered in spatial tag-mediated cooperation models. Here we show, using computer simulations of a spatial model of evolutionary games with organismal migration, that tag-based segregation and homophilic cooperation arise for a wide range of parameters. In the meantime, our results also show another evolutionarily stable outcome, where a high level of heterophilic cooperation is maintained in spatially well-mixed patterns. We found that these two different forms of tag-mediated cooperation appear alternately as the parameter for temptation to defect is increased.