Aspiring to the fittest and promotion of cooperation in the prisoner's dilemma game

TL;DR

This paper introduces a simple rule in evolutionary games that favors selecting the fittest players for strategy updates, which surprisingly promotes cooperation even when defectors initially have higher fitness.

Contribution

The study demonstrates that biasing strategy adoption towards the fittest players enhances cooperation, revealing a negative feedback mechanism and network effects influencing evolutionary outcomes.

Findings

Positive bias towards fittest players promotes cooperation.

The effect is robust across different uncertainties and network structures.

Bias alters interaction networks, affecting strategy evolution.

Abstract

Strategy changes are an essential part of evolutionary games. Here we introduce a simple rule that, depending on the value of a single parameter $w$, influences the selection of players that are considered as potential sources of the new strategy. For positive $w$ players with high payoffs will be considered more likely, while for negative $w$ the opposite holds. Setting $w$ equal to zero returns the frequently adopted random selection of the opponent. We find that increasing the probability of adopting the strategy from the fittest player within reach, i.e. setting $w$ positive, promotes the evolution of cooperation. The robustness of this observation is tested against different levels of uncertainty in the strategy adoption process and for different interaction network. Since the evolution to widespread defection is tightly associated with cooperators having a lower fitness than defectors, the fact that positive values of $w$ facilitate cooperation is quite surprising. We show that the results can be explained by means of a negative feedback effect that increases the vulnerability of defectors although initially increasing their survivability. Moreover, we demonstrate that the introduction of $w$ effectively alters the interaction network and thus also the impact of uncertainty by strategy adoptions on the evolution of cooperation.