Probabilities of cooperative moves in all 67 symmetric ordinal two-player two-moves games

The symmetric 2x2 one-shot game is one of the simplest and most commonly used representations of strategic conflict. Among others, it includes the prisoner’s dilemma, the game of chicken, the volunteer’s dilemma, and the assurance game. All of these games share three characteristics: (1) both players have to make a single choice between two options; (2) they decide simultaneously; and (3) the payoff structure is symmetric. Typically, social scientists who examine (symmetric) 2x2 one-shot games either focus on one game or compare a small number of such games. There are comparatively few studies which analyzed (symmetric) 2x2 one-shot games in a more comprehensive manner. The goal of the present paper is to initiate research on the strategies people use to play any or all symmetric ordinal two-player two-moves games. We propose comparisons between eight different strategies. As will be shown, this analysis lays the groundwork for many possible follow-up projects

The Role of Certainty in a Two-Person Volunteer’s Dilemma

In the standard volunteer’s dilemma (VoD), a single prosocial act (i.e., volunteering) yields the optimal overall outcome. Whereas the volunteer’s outcome is certain, the defector’s outcome depends on what others do. This research addressed the confounding of prosocial responses with uncertainty avoidance in the standard VoD. In Experiment 1, participants (N = 102) considered 18 hypothetical one-shot two-person VoD scenarios with certain, risky, and uncertain outcomes when volunteering. In Experiment 2, participants (N = 496) considered three hypothetical one-shot two-person VoD scenarios; a certain VoD and two uncertain VoDs of which one had a lower expected collective outcome of volunteering than the certain VoD and the other a higher one. Results suggest that volunteering does not reflect a desire to avoid uncertainty but to maximize expected collective outcomes, reinforcing the assumption that the high volunteering rates we see in a standard VoD are due to social/moral preferences and social projection

The role of certainty in a two-person volunteer’s dilemma

In the standard volunteer’s dilemma (VoD), a single prosocial act (i.e., volunteering) yields the optimal overall outcome. Whereas the volunteer’s outcome is certain, the defector’s outcome depends on what others do. This research addressed the confounding of prosocial responses with uncertainty avoidance in the standard VoD. In Experiment 1, participants (N = 102) considered 18 hypothetical one-shot two-person VoD scenarios with certain, risky, and uncertain outcomes when volunteering. In Experiment 2, participants (N = 496) considered three hypothetical one-shot two-person VoD scenarios; a certain VoD and two uncertain VoDs of which one had a lower expected collective outcome of volunteering than the certain VoD and the other a higher one. Results suggest that volunteering does not reflect a desire to avoid uncertainty but to maximize expected collective outcomes, reinforcing the assumption that the high volunteering rates we see in a standard VoD are due to social/moral preferences and social projection

PsycINFO classification: 2340

Abstract Orthodox game theory and social preference models cannot explain why people cooperate in many experimental games or how they manage to coordinate their choices. The theory of evidential decision making provides a solution, based on the idea that people tend to project their own choices onto others, whatever these choices might be. Evidential decision making preserves methodological individualism, and it works without recourse to social preferences. Rejecting methodological individualism, team reasoning is a thinly disguised resurgence of the group mind fallacy, and the experiments reported by Colman et al

Attribution and Categorization Effects in the Representation of Gender Stereotypes

Social stereotypes involve judgments of how typical certain personality traits are of a group. According to the attribution hypothesis, judgments of trait typicality depend on the perceived prevalence of the trait in the target group. According to the categorization hypothesis, such judgments depend on the degree to which a trait is thought to be more or less prevalent in the target group than in a relevant comparison group. A study conducted with women and men as target groups showed that the attribution hypothesis fit the data best when typicality ratings were made in an absolute format. When, however, typicality ratings were made in a comparative format (how typical is the trait of women as compared with men?), both hypotheses received support. Analytical derivation, supported by empirical evidence, showed an inverse relationship between the size of perceived group differences and their weight given in stereotyping. Implications for stereotype measurement and the rationality of social perception are discussed

Game interrupted: The rationality of considering the future

The “problem of points”, introduced by Paccioli in 1494 and solved by Pascal and Fermat 160 years later, inspired the modern concept of probability. Incidentally, the problem also shows that rational decision-making requires the consideration of future events. We show that naïve responses to the problem of points are more future oriented and thus more rational in this sense when the problem itself is presented in a future frame instead of the canonical past frame. A simple nudge is sufficient to make decisions more rational. We consider the implications of this finding for hypothesis testing and predictions of replicability

Outcomes and expectations in dilemmas of trust

Rational trust decisions depend on potential outcomes and expectations of reciprocity. In the trust game, outcomes and expectations correspond to the structural factors of risk and temptation. Two experiments investigated how risk and temptation influenced information search and final decisions in the trust game. The central finding was that trustors underemphasized temptation relative to its effects on the expected value of trust. Instead, trustors made decisions egocentrically, focusing on potential outcomes. In Experiment 1, information search data revealed that trustors often made decisions without learning about the payoffs related to temptation. Experiment 2 investigated whether trustors were able to use temptation to form accurate expectations of reciprocity. Trustors understood, but underestimated, the relationship between temptation and the probability of reciprocity. Moreover, they did not fully consider expectations in their final trust decisions. Changes in potential outcomes had larger effects on trust than comparable changes in expectations. These results suggest that levels of trust are too high when the probability of reciprocity is low and too low when that probability is high

Archaea in Past and Present Geobiochemical Processes and Elemental Cycles

For a long time, Archaea have been considered as an ancient prokaryotic group comprising specialists restricted to narrow ecological niches. This opinion might have been supported by the characteristics of the first well-investigated isolates, being strictly anaerobic (methanogens), halophilic (haloarchaea), or thermophilic (various groups). This is, however, just the tip of the iceberg. Archaea are abundant in all ecosystems. Representatives of the whole domain span the widest range of ecological adaptations from psychrophilic to hyperthermophilic. They tolerate the widest range of pH as well as salt concentrations and use all types of substrates comprising all kinds of organic molecules as well as reduced inorganic compounds

The Effect of Outcome Severity on Moral Judgment and Interpersonal Goals of Perpetrators, Victims, and Bystanders

When two actors have the same mental state but one happens to harm another person (unlucky actor) and the other one does not (lucky actor), the latter elicits a milder moral judgement. To understand how this outcome effect would affect post-harm interactions between victims and perpetrators, we examined how the social role from which transgressions are perceived moderates the outcome effect, and how outcome effects on moral judgements transfer to agentic and communal interpersonal goals. Three vignette experiments (N = 950) revealed similar outcome effects on moral judgement across social roles. In contrast, outcome effects on agentic and communal goals varied by social role: victims exhibited the strongest outcome effects and perpetrators the weakest, with bystanders falling in between. Moral judgement did not mediate the effects of outcome severity on interpersonal goals. We discuss the possibility that outcome severity raises normative expectations regarding post-harm interactions that are unrelated to moral considerations