Hybrid models for achieving and maintaining cooperative symbiotic groups

Societies are composed of groups that interact. Symbiotic groups are those in which agents complement each other in resources that they have in excess. Symbiotic groups are useful especially when the resources in an environment are distributed unevenly, because they enable agents to trade resources easily. However, for trading to happen successfully, agents in symbiotic groups need to cooperate, i.e., they should be willing to donate resources when appropriate. Similarly, if some agents in a symbiotic group are defectors, they should be identified by others and eliminated from the group for the well-being of the remaining agents. Accordingly, we first study Edmonds’ tag-based model of symbiotic groups to understand the lifespan of symbiotic groups (e.g., why some groups live shorter than others). Then, we enhance Edmonds’ model by adding the capability of reciprocal interactions to agents, thus achieving a hybrid model. We capture reciprocity in three different models and study their effects on the elimination of defectors in symbiotic groups. Our experimental results show that the groups that are built with the proposed hybrid model can eliminate more defectors and earlier than tag-based models. Further, the hybrid approach can generate symbiotic groups more effectively and efficiently.