The evolution of lying in well-mixed populations

TL;DR

This study models the evolution of different lie types in well-mixed populations using statistical physics, revealing diverse dynamics and equilibrium states for altruistic, black, spiteful, and Pareto white lies.

Contribution

It introduces a novel application of Monte Carlo simulations to analyze the evolution of various lie types in populations, highlighting complex behaviors and dependencies on payoffs.

Findings

Spiteful lies lead to truthful behavior dominance.

Altruistic and black lies result in high lying but low belief frequencies.

Pareto white lies exhibit complex, variable dynamics depending on payoffs.

Abstract

Lies can have profoundly negative consequences for individuals, groups, and even for societies. Understanding how lying evolves and when it proliferates is therefore of significant importance for our personal and societal well-being. To that effect, we here study the sender-receiver game in well-mixed populations with methods of statistical physics. We use the Monte Carlo method to determine the stationary frequencies of liars and believers for four different lie types. We consider altruistic white lies that favor the receiver at a cost to the sender, black lies that favor the sender at a cost to the receiver, spiteful lies that harm both the sender and the receiver, and Pareto white lies that favor both the sender and the receiver. We find that spiteful lies give rise to trivial behavior, where senders quickly learn that their best strategy is to send a truthful message, whilst receivers likewise quickly learn that their best strategy is to believe the sender's message. For altruistic white lies and black lies, we find that most senders lie while most receivers do not believe the sender's message, but the exact frequencies of liars and non-believers depend significantly on the payoffs, and they also evolve non-monotonically before reaching the stationary state. Lastly, for Pareto white lies we observe the most complex dynamics, with the possibility of both lying and believing evolving with all frequencies between 0 and 1 in dependence on the payoffs. We discuss the implications of these results for moral behavior in human experiments.