How Evolutionary Dynamics Affects Network Reciprocity in Prisoner's Dilemma

Cooperation lies at the foundations of human societies, yet why people cooperate remains a conundrum. The issue, known as network reciprocity, of whether population structure can foster cooperative behavior in social dilemmas has been addressed by many, but theoretical studies have yielded contradictory results so far—as the problem is very sensitive to how players adapt their strategy. However, recent experiments with the prisoner's dilemma game played on different networks and in a specific range of payoffs suggest that humans, at least for those experimental setups, do not consider neighbors' payoffs when making their decisions, and that the network structure does not influence the final outcome. In this work we carry out an extensive analysis of different evolutionary dynamics, taking into account most of the alternatives that have been proposed so far to implement players' strategy updating process. In this manner we show that the absence of network reciprocity is a general feature of the dynamics (among those we consider) that do not take neighbors' payoffs into account. Our results, together with experimental evidence, hint at how to properly model real people's behaviorThis work was supported by the Swiss Natural Science Foundation through grant PBFRP2_145872 and by Ministerio de Economía y Competitividad (Spain) through grant PRODIEVO.Publicad

It Pays to be Nice: The Benefits of Cooperating in Markets

We contribute to the experimental literature by examining the causal effect of partner choice opportunities on the earnings of different cooperative types. We first elicit cooperative types and then randomly assign subjects to a repeated prisoner's dilemma game, with either mutual partner choice or random matching. In each period, the individual who fails to attain a partner is excluded from the group. The results from three experiments show that mutual partner choice enables cooperators to outperform free riders; cooperators tend to earn more than free riders and are less frequently excluded. Our findings are robust with respect to varying group size and whether subjects are reminded about their entire partner and earnings history or only their recent history.publishedVersio

Conflict and Cooperation in Long-Term Contracts

This Article uses the techniques of modern decision analysis and game theory to analyze the decisionmaking strategies of parties to long-term commercial contracts. Most parties to long-term contracts initially allocate the risks of future contingencies and agree – either explicitly or implicitly – to adjust this initial risk-allocation scheme if unanticipated events occur. Once contract risks are initially distributed, however, each party\u27s self-interest may compel them to evade their responsibility rather than adjust cooperatively as originally agreed. Visualizing the interactions between contracting parties as an iterated prisoner\u27s dilemma, the Author attempts to clarify the dynamics of this adjustment process. Professor Scott employs a game theoretic model to demonstrate that two polar behavioral patterns – either conflict or cooperation – would dominate if parties were unable to bargain over adjustment. However, this choice may not occur, he suggests, because even parties that are precluded from negotiating each adjustment option, nevertheless can communicate their intentions to each other. Under these conditions, a cooperative equilibrium will emerge so long as one of the parties commits to a strategy of conditional cooperation before the first adjustment is necessary. Professor Scott notes that in more realistic contractual situations, some breakdowns in patterns of mutual cooperation are inevitable. In actual contract settings, substantial problems of information and enforcement may threaten the parties\u27 efforts to realize a cooperative equilibrium. Nevertheless, he concludes that parties in continuing relationships can invoke various legal and extralegal mechanisms to reduce these information and enforcement deficits and strengthen the existing matrix of social and contractual norms

Evaluating the Role of Personality Trait Information in Social Dilemmas

We investigate whether cooperative behavior in social dilemmas is conditional on information about a partner\u27s personality traits. Using a repeated one-shot continuous strategy Prisoner\u27s Dilemma (two person Public Goods game), we test how information on personality traits of partners influences cooperative actions. Before each game we provide subjects with the rank-order of their partner (relative to all subjects in the session) on one of the personality traits of the Big Five Inventory. Using a within-subjects design we find that subjects are more cooperative when informed that their partner is more ‘Agreeable’ or ‘Open to Experience’. The primary reason for more cooperative behavior is the expectation that partners will give more to the public good

Rehabilitation and social behavior: Experiments in prison

Despite the economic and social significance of crime reduction and criminals’ rehabilitation, research evaluating the effects of incarceration on behavior is surprisingly scarce. We conduct an experiment with 105 prison inmates and complement it with administrative data in order to explore several aspects of their social behavior. We first perform a comprehensive analysis of behavior in three economic games, finding evidence of discrimination against a sample from outside prison. In addition, our regression analysis reveals that inmates generally become less pro-social towards this out-group the longer they remain incarcerated. Finally, we introduce and evaluate a priming intervention that asks inmates to reflect on their time spent in prison. This intervention has a very sizeable and significant impact, increasing pro-sociality towards the out-group. Hence, a simple, low-cost intervention of this sort can have desirable effects in promoting rehabilitation and integration into social and economic life after release

Self Selection Does Not Increase Other-Regarding Preferences among Adult Laboratory Subjects, but Student Subjects May Be More Self-Regarding than Adults

We use a sequential prisoner's dilemma game to measure the other-regarding behavior in samples from three related populations in the upper Midwest of the United States: 100 college students, 94 non-student adults from the community surrounding the college and 1,069 adult trainee truckers in a residential training program. Both of the first two groups were recruited according to procedures commonly used in experimental economics (i.e., via e-mail and bulletin-board advertisements) and therefore subjects self-selected into the experiment. Because the structure of their training program reduced the opportunity cost of participating dramatically, 91% of the solicited trainees participated in the third group, so there was little scope for self-selection in this sample. We find no differences in the elicited other-regarding preferences between the self-selected adults and the adult trainees, suggesting that selection into this type of experiment is unlikely to bias inferences with respect to non-student adult subjects. We also test (and reject) the more specific hypothesis that approval-seeking subjects are the ones most likely to select into experiments. At the same time, we find a large difference between the self-selected students and the self-selected adults from the surrounding community: the students appear considerably less pro-social. Regression results controlling for demographic factors confirm these basic findings.methodology, selection bias, laboratory experiment, field experiment, other-regarding behavior, social preferences, truckload, trucker

Fairness Emergence in Reputation Systems

Reputation systems have been used to support users in making decisions under uncertainty or risk that is due to the autonomous behavior of others. Research results support the conclusion that reputation systems can protect against exploitation by unfair users, and that they have an impact on the prices and income of users. This observation leads to another question: can reputation systems be used to assure or increase the fairness of resource distribution? This question has a high relevance in social situations where, due to the absence of established authorities or institutions, agents need to rely on mutual trust relations in order to increase fairness of distribution. This question can be formulated as a hypothesis: in reputation (or trust management) systems, fairness should be an emergent property. The notion of fairness can be precisely defined and investigated based on the theory of equity. In this paper, we investigate the Fairness Emergence hypothesis in reputation systems and prove that , under certain conditions, the hypothesis is valid for open and closed systems, even in unstable system states and in the presence of adversaries. Moreover, we investigate the sensitivity of Fairness Emergence and show that an improvement of the reputation system strengthens the emergence of fairness. Our results are confirmed using a trace-driven simulation from a large Internet auction site.Trust, Simulation, Fairness, Equity, Emergence, Reputation System

Social decision-making in highly psychopathic offenders – A systematic literature review

Despite their decisions to frequently manipulate or even callously harm others in real life, highly psychopathic individuals often exhibit judgments comparable to individuals low in psychopathy when examined experimentally. This conundrum has generated a rich body of studies exploring social decision-making in psychopathy, but no systematic review to date has identified decision-making as measured in real-world or simulated social interactions in criminal offender samples assessed for psychopathic traits. Out of 807 studies provided by database searching in August 2022, 16 studies were included in this review and revealed behavioral economic games and paradigms for the assessment of aggressive behavior as the two main approaches to dissect social decision-making in offender samples regarding psychopathy. The specific paradigms exposed the multidimensional structure of both, the psychopathy construct and social decision-making. On one side, the distinct affordances of the social tasks, such as trust, power, or reactions to unfairness and provocation shed light on the inconsistent relations of decisions in experimental situations and psychopathy. On the other side, studies analyzing decision outcomes with respect to the distinct psychopathy subcomponents revealed nuanced interference effects with the social decision tasks. The review encourages a differentiated perspective to the psychopathy construct and social decision-making processes alike

On closer inspection : reviewing the debate on whether fish cooperate to inspect predators

This work was funded by an EASTBIO DTP scholarship to A. Li Veiros.Cooperative behaviours, which benefit a recipient, are widespread in the animal kingdom; yet their evolution is not straightforward. Reciprocity, i.e., cooperating with previously experienced cooperative partners, has been suggested to underly cooperation, but has been contested throughout the years. Once a textbook example of reciprocity was cooperative predator inspection, where one or several individuals leave their group to approach a potential threat. Each can at any point stop or retreat, increasing the risk for its partner. It was suggested that inspecting individuals follow a specific reciprocal strategy called tit-for-tat, i.e., cooperating on the first move and then copying the partner's last move. Numerous studies provide evidence to support the claim that fish cooperate to inspect predators, including three-spined sticklebacks (Gasterosteus aculeatus), guppies (Poecilia reticulata) and minnows (Phoxinus phoxinus). However, over the past few decades some scholars have expressed scepticism whether predator inspection is indeed a cooperative behaviour or rather a case of by-product mutualism, which describes behaviours that benefit a partner as a corollary of an otherwise selfish behaviour. For instance, it has been shown that pairs of fish moving in unfamiliar environments appear to coordinate movements even in the absence of predators. Many studies have also used coarse measures of overall approach rates towards predators rather than the fine-grained analyses necessary to infer tit-for-tat in cooperative inspections. Now is the time to return to the question of cooperative predator inspection with new tools and approaches to resolve a decades-old debate.Publisher PDFPeer reviewe