Crime, punishment, and evolution in an adversarial game

Games, 2016

We extend a standard two-person, non-cooperative, non-zero sum, imperfect inspection game, considering a large population of interacting inspectees and a single inspector. Each inspectee adopts one strategy, within a finite/infinite bounded set of strategies returning increasingly illegal profits, including compliance. The inspectees may periodically update their strategies after randomly inter-comparing the obtained payoffs, setting their collective behaviour subject to evolutionary pressure. The inspector decides, at each update period, the optimum fraction of his/her renewable budget to invest on his/her interference with the inspectees' collective effect. To deter the inspectees from violating, he/she assigns a fine to each illegal strategy. We formulate the game mathematically, study its dynamics and predict its evolution subject to two key controls, the inspection budget and the punishment fine. Introducing a simple linguistic twist, we also capture the corresponding version of a corruption game.

PLoS ONE, 2013

Direct reciprocity is a mechanism for the evolution of cooperation. For the iterated prisoner's dilemma, a new class of strategies has recently been described, the so-called zero-determinant strategies. Using such a strategy, a player can unilaterally enforce a linear relationship between his own payoff and the co-player's payoff. In particular the player may act in such a way that it becomes optimal for the co-player to cooperate unconditionally. In this way, a player can manipulate and extort his co-player, thereby ensuring that the own payoff never falls below the co-player's payoff. However, using a compliant strategy instead, a player can also ensure that his own payoff never exceeds the co-player's payoff. Here, we use adaptive dynamics to study when evolution leads to extortion and when it leads to compliance. We find a remarkable cyclic dynamics: in sufficiently large populations, extortioners play a transient role, helping the population to move from selfish strategies to compliance. Compliant strategies, however, can be subverted by altruists, which in turn give rise to selfish strategies. Whether cooperative strategies are favored in the long run critically depends on the size of the population; we show that cooperation is most abundant in large populations, in which case average payoffs approach the social optimum. Our results are not restricted to the case of the prisoners dilemma, but can be extended to other social dilemmas, such as the snowdrift game. Iterated social dilemmas in large populations do not lead to the evolution of strategies that aim to dominate their co-player. Instead, generosity succeeds.

Physica A: Statistical Mechanics and its Applications, 2013

We look for optimal strategies to defend valuable goods from the attacks of offenders. Two complementary approaches are used: agent-based modeling and game theory. A Nash equilibrium is found considering the good values and the chance of success. The bifurcation diagram of the Nash-equilibrium as a function of the ∧ relative values of the goods is non-monotonic.

PLoS ONE, 2014

The punishment effect on social behavior is analyzed within the strategic interaction framework of Cellular Automata and computational Evolutionary Game Theory. A new game, called Social Honesty (SH), is proposed. The SH game is analyzed in spatial configurations. Probabilistic punishment is used as a dishonesty deterrence mechanism. In order to capture the intrinsic uncertainty of social environments, payoffs are described as random variables. New dynamics, with a new relation between punishment probability and punishment severity, are revealed. Punishment probability proves to be more important than punishment severity in guiding convergence towards honesty as predominant behavior. This result is confirmed by empirical evidence and reported experiments. Critical values and transition intervals for punishment probability and severity are identified and analyzed. Clusters of honest or dishonest players emerge spontaneously from the very first rounds of interaction and are determinant for the future dynamics and outcomes. Citation: Cremene M, Dumitrescu D, Cremene L (2014) A Strategic Interaction Model of Punishment Favoring Contagion of Honest Behavior. PLoS ONE 9(1): e87471.

Proceedings of the 8th annual conference on Genetic and evolutionary computation - GECCO '06, 2006

The Prisoner's Dilemma and the Public Goods Game are models to study mechanisms leading to the evolution of cooperation. From a simplified rational and egoistic perspective there should be no altruistic cooperation in these games at all. Previous studies observed circumstances under which cooperation can emerge. This paper demonstrates that high-order punishment opportunities can maintain a higher cooperation level in an agent based simulation of the evolution of cooperation.

The standard economic model of crime emphasizes the individual rationality and agency of criminals. On the other hand, sociological theories typically emphasize the importance of social forces. This essay surveys a recent strand of literature on law enforcement that bridges these two approaches. Using the tools of game theory, it investigates crime as the outcome of the interaction between rational individuals. The survey shows that this analysis leads to a substantially richer set of hypotheses regarding the effect of enforcement than the standard economic model, depending on the classification of the social context, or game, in which agents operate. In doing so, it brings rational choice theories in line with long-standing insights in the field of criminology, as well as providing new analytical distinctions and generalizations.

2014

It has been argued that punishment promotes the evolution of cooperation when mutation rates are high (i.e. when agents engage in 'exploration dynamics'). Mutations maintain a steady supply of agents that punish free-riders, and thus free-riders are at a disadvantage. Recent experiments, however, have demonstrated that free-riders sometimes also pay to punish cooperators. Inspired by these empirical results, theoretical work has explored evolutionary dynamics where mutants are rare, and found that punishment does not promote the evolution of cooperation when this 'anti-social punishment' is allowed. Here we extend previous theory by studying the effect of anti-social punishment on the evolution of cooperation across higher mutation rates, and by studying voluntary as well as compulsory Public Goods Games. We find that for intermediate and high mutation rates, adding punishment does not promote cooperation in either compulsory or voluntary public goods games if anti-social punishment is possible: Mutations generate agents that punish cooperators just as frequently as agents that punish defectors, and these two effects cancel each other out. These results raise questions about the effectiveness of punishment for promoting cooperation when mutations are common, and highlight how decisions about which strategies to include in the strategy set can have profound effects on the resulting dynamics.

Social punishment, whereby cooperators punish defectors , has been suggested as an important mechanism that promotes the emergence of cooperation or maintenance of social norms in the context of the one-shot (i.e. non-repeated) interaction. However, whenever antisocial punishment, whereby defectors punish cooper-ators, is available, this antisocial behavior outperforms social punishment, leading to the destruction of cooperation. In this paper, we use evolutionary game theory to show that this antisocial behavior can be efficiently restrained by relying on prior commitments, wherein agents can arrange, prior to an interaction, agreements regarding posterior compensation by those who dishonor the agreements. We show that, although the commitment mechanism by itself can guarantee a notable level of cooperation, a significantly higher level is achieved when both mechanisms, those of proposing prior commitments and of punishment, are available in co-presence. Interestingly, social punishment prevails and dominates in this system as it can take advantage of the commitment mechanism to cope with antisocial behaviors. That is, establishment of a commitment system helps to pave the way for the evolution of social punishment and abundant cooperation, even in the presence of antisocial punishment.

Journal of Economic Behavior & Organization, 1996

Evolutionary models in economics have often been criticized for failing to allow for rational, maximizing behavior. The present paper represents a step toward correcting this deficiency, by introducing rational actors into an evolutionary model of the finitely repeated Prisoners' Dilemma. At the same time, the model endogenizes the uncertainty postulated in the classic model of Kreps et al. (1982), thus explaining cooperation by rational actors in the finitely repeated Prisoners' Dilemma. A testable implication of the model is that the level of voluntary cooperation in a society will be relatively high where geographical mobility is relatively low. JEL clu,ssification: C72; C73