One-shot Prisoner Research Articles

Siblings, strangers, and the surge of altruism

We demonstrate how altruism can surge in a population of nonaltruists. We assume that each individual plays a one-shot prisoner’s dilemma game with his or her sibling, or with a stranger, and that the probability that an individual survives to reproduce is proportional to his or her payoff in this game. We model the formation of couples and the rule of imitation of parents and of nonparents. We then ask what happens to the proportion of altruists in the population. We specify a case where the unique and stable equilibrium is one in which the entire population will consist of altruists.

The Evolution of Trust and Cooperation between Strangers: A Computational Model

Social and economic exchanges often occur between strangers who cannot rely on past behavior or the prospect of future interactions to establish mutual trust. Game theorists formalize this problem as a one-shot prisoner's dilemma and predict mutual noncooperation. Recent studies, however, challenge this conclusion. If the game provides an option to exit (or to refuse to play), strategies based on projection (of a player's intentions) and detection (of the intentions of a stranger) can confer a cooperator's advantage. Yet previous research has not found a way for these strategies to evolve from a random start or to recover from invasion by aggressive strategies that feign trustworthiness. The authors use computer simulation to show how trust and cooperation between strangers can evolve without formal or informal social controls. The outcome decisively depends, however, on two structural conditions : the payoff for refusing to play, and the embeddedness of interaction. Effective norms for trusting strangers emerge locally, in exchanges between neighbors, and then diffuse through weak ties to outsiders

NASH EQUILIBRIUM WITH LOWER PROBABILITIES

We generalize the concept of Nash equilibrium in mixed strategies for strategic form games to allow for ambiguity in the players' expectations. In contrast to other contributions, we model ambiguity by means of so-called lower probability measures or belief functions, which makes it possible to distinguish between a player's assessment of ambiguity and his attitude towards ambiguity. We also generalize the concept of trembling hand perfect equilibrium. Finally, we demonstrate that for certain attitudes towards ambiguity it is possible to explain cooperation in the one-shot Prisoner's Dilemma in a way that is in accordance with some recent experimental findings.

Information Preferences and Social Value Orientations in a Prisoner's Dilemma Game

This research examined the relationship between individual differences in social value orientations (cooperation, equality, individualism, and competition) and selective information preferences. One hundred and fifty-nine female college students participated in an one-shot prisoner's dilemma game, and the payoff matrices they reproduced were assessed. The results clearly showed that individuals with different social value orientations selectively processed different kinds of information contained in the payoff matrix. The observed linkage between information preferences and social value orientations implied the existence of decision making processes unique to each orientation. Further more, it was also suggested that social value orientations or individual cooperative tendencies would be closely related to their information processing complexity.

“フォールス・コンセンサス”が“フォールス（誤り）”でなくなるとき １回限りの囚人のジレンマを用いた実験研究

An experiment was conducted to investigate social implications of false consensus effect (what results will occurred at the group level when individuals act on their false consensus) in a “selective-play” situation, The results demonstrated that, under specified situations (in the selective-play situation, derived from Orbell and Dawes, 1993, and in the situation where it is difficult to predict partners' action, derived from Yamagishi and Yamagishi (1994)), the behavior of subjects who acted on their false consensus changed the situation such that their expectations about partners' cooperativeness was no longer “false.” This is because cooperative subjects were able to find other cooperative subjects in the selective-play situation. The results further suggested that having a false consensus about partners' cooperativeness provided an advantage in the one-shot prisoner's dilemma situation.

Long-run cooperation in the one-shot Prisoner's Dilemma: A hierarchic evolutionary approach

This paper proposes a hierarchic evolutionary model leading to long-run cooperation in the Prisoner's Dilemma. The population is segmented into groups, and evolution and interaction take place ‘in parallel’ at two levels: (i) within groups at the lower level; (ii) among groups at the higher one. At each of these levels, what performs currently best tends to be imitated. On the other hand, occasionally, individuals also experiment with (or mutate to) some new strategy. If the number of groups is sufficiently large, the long-run (invariant) distribution of the process is shown to be concentrated on the cooperative outcome.

Cooperation in the One-shot Prisoner's Dilemma Based on Expectations of Reciprocity

By applying the“illusion of control”hypothesis (Karp et al., 1993), originally developed to explain ingroup favoritism in the minimal group experiments, to a prisoner's dilemma (PD) situation, we predicted that the cooperation rate of players would be affected by their illusion of control. We used a sequential PD in which one player decides before the other does to maximize and minimize feasibility of illusion of control. Specifically, the following three hypotheses were successfully tested. Hypothesis 1: The decision of the second player in a sequential PD would be affected by the choice of the first player, cooperating with the cooperative first player and defecting with the defective first player. Hypothesis 2: Compared to the players of ordinary simultaneous one-shot PD (simultaneous condition), the player who decides first and whose decision is informed to the second player before the latter makes his/her decision would feel controllability over the second player and thus would cooperate more. Hypothesis 3: Compared to the simltaneous condition, players uwould cooperate less when they know (without being informed of the first player's choice) that the first player has already made his/her decision. The second experiment was conducted to replicate Hypothesis 3, the most important hypothesis of the three. The hypothesis was also supported in the second experiment.

Group Size and One-Shot Collective Action

Situations of collective actions have been modeled as iterated N- person Prisoner's Dilemma games or N- person Chicken games. Although there exists some experimental evidence with regard to the effects of group size in iterated dilemmas, very little attention has been given to one-shot social dilemmas. This article argues that some social dilemmas can be modeled as one-shot games. Furthermore, it discusses and provides experimental evidence on the effects of group size on cooperation in four different one-shot games. The results confirm the hypotheses that there are no group-size effects in the one-shot Prisoner's Dilemma and in the one-shot Chicken game. However, group size does have a negative effect on the cooperation rate in both the Volunteer's Dilemma and in the Assurance game.

Cooperation in a one-shot Prisoners' Dilemma

In this paper, we model social interactions which are characteristic of large economies. The key properties of this model are: (1) agents are randomly matched over time to engage in a Prisoners' Dilemma; (2) each agent routinely interacts with a proper subset of the other agents; and (3) each agent has highly imperfect information about the past conduct of other agents. For this setting, we show the optimality of a rule of thumb which does not discriminate between encounters with agents that one regularly meets and encounters with agents that one never expects to meet again. This rule of thumb generates cooperative behavior in all encounters. Journal of Economic Literature Classification Numbers: C72, D74.

Emergence of cooperation in one-short prisoner's dilemmas and the role of trust

The main purpose of this study is to apply the "selective play paradigm" to explain how cooperation emerges in one-shot prisoner's dilemmas. A unique feature of the selective play paradigm is the option for not playing a PD game. For this purpose, a computer simulation of 100-actor groups was conducted. At the beginning of each replication, each simulated actor was randomly assigned to one of eleven levels of trust, which indicates the actor's estimate of the overall cooperation rate in the group. Each simulated actor, then, decided whether or not to interact with the previous partner based on the calculated expected gains from interacting with one of the other partners. Results of the simulation show that: (1) when substantial opportunity costs exist, having a high level of trust benefits the actor; (2) the above effect of trust depends on the actor's cooperativeness in PD games; (3) but does not depend on the overall cooperation rate in the group.

Cooperation by indirect revelation through strategic behavior

The paper deals with a one-shot prisoners' dilemma when the players have an option to go to court but cannot verify their testimonies. To solve the problem a second stage is added to a game. At the first stage the players are involved in the prisoners' dilemma and at the second stage they play another game in which their actions are verifiable. In such a setup the information about the actions chosen at the prisoners' dilemma stage can be revealed through strategic behavior of the players during second stage. A mechanism for such revelation in the extended game is described. It provides an existence of a unique sequential equilibrium, which may be obtained by an iterative elimination of dominated strategies and has a number of desirable properties.

The evolution of one-shot cooperation: An experiment

Can people rationally advance their own material interests by cooperating in one-shot prisoner's dilemmas, even when there is no possibility of being punished for defection? We outline a model that describes how such cooperation could evolve if the presence of a cooperative disposition can be discerned by others. We test the model's key assumption with an experiment in which we find that subjects who interacted for thirty minutes before playing one-shot prisoner's dilemmas with two others were substantially more accurate than chance in predicting their partner's decisions.

Stable Cooperation in Iterated Prisoners' Dilemmas

When does self-interest counsel cooperation? This question pertains both to the labile behaviors produced by rational deliberation and to the more instinctive and fixed behaviors produced by natural selection. In both cases, a standard starting point for the investigation is the one-shot prisoners' dilemma. In this game, each player has the option of producing one or the other of two behaviors (labeled “cooperate” and “defect”). The pay-offs to the row player are as follows:

Efficiency in evolutionary games: Darwin, nash and the secret handshake

This paper considers any evolutionary game possessing several evolutionarily stable strategies, or ESSs, with differing payoffs. A mutant is introduced which will "destroy" any ESS which yields a lower payoff than another. This mutant possesses a costless signal and also conditions on the presence of this signal in each opponent. The mutant then can protect itself against a population playing an inefficient ESS by matching this against these non-signalers. At the same time, the mutants can achieve the more efficient ESS against the signaling mutant population itself. This construction is illustrated by means of the simplest possible example, a co-ordination game. The one-shot prisoner's dilemma is used to illustrate how a superior outcome which is not induced by an ESS may be temporarily but not permanently attained. In the case of the repeated prisoner's dilemma, the present argument seems to render the "evolution of co-operation" ultimately inevitable.