Evolution of cooperation driven by zealots

TL;DR

This paper presents a model showing that a small fraction of committed cooperators can significantly promote widespread cooperation in social dilemma games, even when defection is more profitable.

Contribution

It introduces a new evolutionary dynamics model linking experimental findings with the emergence of cooperation driven by zealots.

Findings

A small fraction of zealots can induce widespread cooperation.

Weak selection pressure allows cooperation to spread via mimicry.

Zealous cooperators can lead to full cooperation in the population.

Abstract

Recent experimental results with humans involved in social dilemma games suggest that cooperation may be a contagious phenomenon and that the selection pressure operating on evolutionary dynamics (i.e., mimicry) is relatively weak. I propose an evolutionary dynamics model that links these experimental findings and evolution of cooperation. By assuming a small fraction of (imperfect) zealous cooperators, I show that a large fraction of cooperation emerges in evolutionary dynamics of social dilemma games. Even if defection is more lucrative than cooperation for most individuals, they often mimic cooperation of fellows unless the selection pressure is very strong. Then, zealous cooperators can transform the population to be even fully cooperative under standard evolutionary dynamics.