Recidivism and rehabilitation of criminal offenders: a carrot and stick evolutionary game

PLoS One. 2014 Jan 16;9(1):e85531. doi: 10.1371/journal.pone.0085531. eCollection 2014.

Abstract

Motivated by recent efforts by the criminal justice system to treat and rehabilitate nonviolent offenders rather than focusing solely on their punishment, we introduce an evolutionary game theoretic model to study the effects of "carrot and stick" intervention programs on criminal recidivism. We use stochastic simulations to study the evolution of a population where individuals may commit crimes depending on their past history, surrounding environment and, in the case of recidivists, on any counseling, educational or training programs available to them after being punished for their previous crimes. These sociological factors are embodied by effective parameters that determine the decision making probabilities. Players may decide to permanently reform or continue engaging in criminal activity, eventually reaching a state where they are considered incorrigible. Depending on parameter choices, the outcome of the game is a society with a majority of virtuous, rehabilitated citizens or incorrigibles. Since total resources may be limited, we constrain the combined punishment and rehabilitation costs per crime to be fixed, so that increasing one effort will necessarily decrease the other. We find that the most successful strategy in reducing crime is to optimally allocate resources so that after being punished, criminals experience impactful intervention programs, especially during the first stages of their return to society. Excessively harsh or lenient punishments are less effective. We also develop a system of coupled ordinary differential equations with memory effects to give a qualitative description of our simulated societal dynamics. We discuss our findings and sociological implications.

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Algorithms
  • Computer Simulation
  • Crime / prevention & control*
  • Crime / psychology
  • Criminals / psychology*
  • Game Theory
  • Humans
  • Models, Psychological
  • Monte Carlo Method
  • Population Dynamics
  • Punishment / psychology*
  • Stochastic Processes

Grants and funding

This work was supported by the National Science Foundation through grants DMS-1021850 (to MRD) and DMS-1021818 (to TC), and by the ARO through the MURI grant W911NF-11-1-0332 (to MRD) and grant 58386MA (to TC). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.