Imperfect Imitation Can Enhance Cooperation

TL;DR

This paper introduces a new stochastic imitation rule that combines unconditional imitation with another rule, leading to higher cooperation levels in social dilemmas across various network structures.

Contribution

It proposes a novel hybrid imitation rule that enhances cooperation, revealing a nontrivial effect due to timescale separation at cluster interfaces.

Findings

Hybrid rule outperforms individual rules in promoting cooperation

Effect is robust across different network topologies

Timescale separation explains the cooperative enhancement

Abstract

The promotion of cooperation on spatial lattices is an important issue in evolutionary game theory. This effect clearly depends on the update rule: it diminishes with stochastic imitative rules whereas it increases with unconditional imitation. To study the transition between both regimes, we propose a new evolutionary rule, which stochastically combines unconditional imitation with another imitative rule. We find that, surprinsingly, in many social dilemmas this rule yields higher cooperative levels than any of the two original ones. This nontrivial effect occurs because the basic rules induce a separation of timescales in the microscopic processes at cluster interfaces. The result is robust in the space of 2x2 symmetric games, on regular lattices and on scale-free networks.