A double-edged sword: Benefits and pitfalls of heterogeneous punishment in evolutionary inspection games

TL;DR

This paper models criminal behavior using an extended inspection game with heterogeneous punishers and ordinary individuals, revealing complex dynamics and phase transitions that hinder complete crime eradication.

Contribution

It introduces a three-strategy model with diverse punishers, uncovering intricate phase transitions and the persistent challenge of eliminating crime.

Findings

Multiple phase transitions occur as temptation varies.

Heterogeneous punishers create complex strategic dynamics.

Crime persists despite various punishment strategies.

Abstract

As a simple model for criminal behavior, the traditional two-strategy inspection game yields counterintuitive results that fail to describe empirical data. The latter shows that crime is often recurrent, and that crime rates do not respond linearly to mitigation attempts. A more apt model entails ordinary people who neither commit nor sanction crime as the third strategy besides the criminals and punishers. Since ordinary people free-ride on the sanctioning efforts of punishers, they may introduce cyclic dominance that enables the coexistence of all three competing strategies. In this setup ordinary individuals become the biggest impediment to crime abatement. We therefore also consider heterogeneous punisher strategies, which seek to reduce their investment into fighting crime in order to attain a more competitive payoff. We show that this diversity of punishment leads to an explosion of complexity in the system, where the benefits and pitfalls of criminal behavior are revealed in the most unexpected ways. Due to the raise and fall of different alliances no less than six consecutive phase transitions occur in dependence on solely the temptation to succumb to criminal behavior, leading the population from ordinary people-dominated across punisher-dominated to crime-dominated phases, yet always failing to abolish crime completely.