Effects of dimers on cooperation in the spatial prisoner's dilemma game

TL;DR

This paper studies how introducing dimers, pairs of players with synchronized strategies, affects cooperation in the spatial prisoner's dilemma game across different network structures and community configurations.

Contribution

It reveals how different types of dimers influence cooperation levels and draws parallels between dimers and self-interactions in structured populations.

Findings

Dimer interactions can increase cooperation depending on network type.

Non-interacting dimers boost cooperation in multi-community settings.

Dimers facilitate information exchange between communities.

Abstract

We investigate the evolutionary prisoner's dilemma game in structured populations by introducing dimers, which are defined as that two players in each dimer always hold a same strategy. We find that influences of dimers on cooperation depend on the type of dimers and the population structure. For those dimers in which players interact with each other, the cooperation level increases with the number of dimers though the cooperation improvement level depends on the type of network structures. On the other hand, the dimers, in which there are not mutual interactions, will not do any good to the cooperation level in a single community, but interestingly, will improve the cooperation level in a population with two communities. We explore the relationship between dimers and self-interactions and find that the effects of dimers are similar to that of self-interactions. Also, we find that the dimers, which are established over two communities in a multi-community network, act as one type of interaction through which information between communities is communicated by the requirement that two players in a dimer hold a same strategy.