The Emergence of Relationship-based Cooperation.

Bo Xu,Jianwei Wang

doi:10.1038/srep16447

Abstract

This paper investigates the emergence of relationship-based cooperation by coupling two simple mechanisms into the model: tie strength based investment preference and homophily assumption. We construct the model by categorizing game participants into four types: prosocialists (players who prefers to invest in their intimate friends), antisocialists (players who prefer to invest in strangers), egoists (players who never cooperate) and altruists (players who cooperate indifferently with anyone). We show that the relationship-based cooperation (prosocialists) is favored throughout the evolution if we assume players of the same type have stronger ties than different ones. Moreover, we discover that strengthening the internal bonds within the strategic clusters further promotes the competitiveness of prosocialists and therefore facilitates the emergence of relationship-based cooperation in our proposed scenarios. The robustness of the model is also tested under different strategy updating rules and network structures. The results show that this argument is robust against the variations of initial conditions and therefore can be considered as a fundamental theoretical framework to study relationship-based cooperation in reality.

Highlights

We introduce a tie strength model to explore the evolution of relationship-based cooperation under a game-theoretic framework
We show that the emergence of relationship-based cooperation can be dramatically enhanced by coupling two simple mechanisms
The first mechanism presumes a tie strength-based investment preference, where players tend to investment more to the intimate friends

Summary

OPEN The Emergence of Relationshipbased Cooperation

Bo Xu1 & Jianwei Wang[1] received: 20 July 2015 accepted: 14 October 2015 Published: 16 November 2015. Parents devote efforts to kids, friends helps each other when they are in need Despite that such cooperative behaviors usually require the sacrifice of the individual benefits, it turns out that this type of relationship-based cooperation is favored by natural selection[1,2,3,4,5]. This assumption is termed as homophily or “birds of a feather”[28], which elaborates the fact that similar individuals tend to form strong ties Under such simple settings, this research constructs a theoretical framework to explore the evolutionary process of relationship-based interactions and explain the emergence of prosocial cooperation observed in social life. We reveal that the existence of heterogeneous tie strength and the resulted preferential investment preference enables prosocialists outperform other types of players throughout evolution Strengthening such investment preference can further enhance the level of prosocial cooperation in prisoner’s dilemma games.

The Model

Simulation Results and Discussions

Prosocialist Antisocialist Egoist Altruist

Summary

Additional Information