Conformity Hinders the Evolution of Cooperation on Scale-Free Networks

TL;DR

This paper investigates how conformity influences the evolution of cooperation in networked populations, revealing that conformity weakens the cooperative advantage of scale-free networks.

Contribution

It introduces a model combining pay-off and conformist biases in imitation, showing how conformity diminishes the cooperative benefits of scale-free network structures.

Findings

Conformity increases cooperation on rings.

Scale-free networks lose their cooperation-promoting advantage with conformity.

Hubs in scale-free networks become more susceptible to influence.

Abstract

We study the effects of conformity, the tendency of humans to imitate locally common behaviors, in the evolution of cooperation when individuals occupy the vertices of a graph and engage in the one-shot Prisoner's Dilemma or the Snowdrift game with their neighbors. Two different graphs are studied: rings (one-dimensional lattices with cyclic boundary conditions) and scale-free networks of the Barabasi-Albert type. The proposed evolutionary-graph model is studied both by means of Monte Carlo simulations and an extended pair-approximation technique. We find improved levels of cooperation when evolution is carried on rings and individuals imitate according to both the traditional pay-off bias and a conformist bias. More important, we show that scale-free networks are no longer powerful amplifiers of cooperation when fair amounts of conformity are introduced in the imitation rules of the players. Such weakening of the cooperation-promoting abilities of scale-free networks is the result of a less biased flow of information in scale-free topologies, making hubs more susceptible of being influenced by less-connected neighbors.