Emergence of multilevel selection in the prisoner's dilemma game on coevolving random networks

TL;DR

This paper demonstrates that a coevolutionary process involving link deletion and addition in random networks fosters multilevel selection, which promotes cooperation in the prisoner's dilemma game despite ongoing network randomness.

Contribution

It introduces a novel coevolutionary rule that maintains network heterogeneity and induces multilevel selection, enhancing cooperation in social dilemmas.

Findings

Multilevel selection emerges spontaneously under the coevolutionary rule.

Cooperation persists across a wide range of temptation values.

Network heterogeneity is preserved despite random link modifications.

Abstract

We study the evolution of cooperation in the prisoner's dilemma game, whereby a coevolutionary rule is introduced that molds the random topology of the interaction network in two ways. First, existing links are deleted whenever a player adopts a new strategy or its degree exceeds a threshold value, and second, new links are added randomly after a given number of game iterations. These coevolutionary processes correspond to the generic formation of new and deletion of existing links that, especially in human societies, appear frequently as a consequence of ongoing socialization, change of lifestyle or death. Due to the counteraction of deletions and additions of links the initial heterogeneity of the interaction network is qualitatively preserved, and thus cannot be held responsible for the observed promotion of cooperation. Indeed, the coevolutionary rule evokes the spontaneous emergence of a powerful multilevel selection mechanism, which despite of the sustained random topology of the evolving network, maintains cooperation across the whole span of defection temptation values.