Does competitive winning increase subsequent cheating?

In this preregistered study, we attempted to replicate and substantially extend a frequently cited experiment by Schurr and Ritov, published in 2016, suggesting that winners of pairwise competitions are more likely than others to steal money in subsequent games of chance against different opponents, possibly because of an enhanced sense of entitlement among competition winners. A replication seemed desirable because of the relevance of the effect to dishonesty in everyday life, the apparent counterintuitivity of the effect, possible problems and anomalies in the original study, and above all the fact that the researchers investigated only one potential explanation for the effect. Our results failed to replicate Schurr and Ritov's basic finding: we found no evidence to support the hypotheses that either winning or losing is associated with subsequent cheating.

The Tavistock First-Time Parent Study: a pilot randomised controlled feasibility trial of a brief couple-focused perinatal intervention to reduce inter-parental discord.

Numerous studies report that some first-time parents experience a decline in relationship quality and an increase in conflict after the birth of a first baby. Inter-parental discord that is frequent, intense, and poorly resolved increases the likelihood of relationship breakdown and adversely impacts child development. We investigated the feasibility of a brief preventative couple-focused psychotherapeutic intervention in the perinatal period in a general population sample.

Do say "thank you": verbal expressions of politeness and gratitude influence interpersonal perceptions.

This study investigates how expressions of politeness and gratitude influence interpersonal perceptions of a job interviewee's trustworthiness and personality. A pilot study disentangled politeness and gratitude ratings for phrases. Statements expressing politeness with high or low gratitude were selected and inserted into a job-interview transcript, with the female interviewee depicted as either the same age or 20 years older than the 136 participants.

The persuasive power of knowledge: Testing the confidence heuristic.

According to the confidence heuristic, people are confident when they know they are right, and their confidence makes them persuasive. Previous experiments have investigated the confidence-persuasiveness aspect of the heuristic but not the integrated knowledge-confidence-persuasiveness hypothesis. We report 3 experiments to test the heuristic using incentivized interactive decisions with financial outcomes in which pairs of participants with common interests attempted to identify target stimuli after conferring, only 1 pair member having strong information about the target.

Persistent cooperation and gender differences in repeated Prisoner's Dilemma games: Some things never change.

In the finite-horizon repeated Prisoner's Dilemma, a compelling backward induction argument shows that rational players will defect in every round, following the uniquely optimal Nash equilibrium path. It is frequently asserted that cooperation gradually declines when a Prisoner's Dilemma is repeated multiple times by the same players, but the evidence for this is unconvincing, and a classic experiment by Rapoport and Chammah in the 1960s reported that cooperation eventually recovers if the game is repeated hundreds of times. They also reported that men paired with men cooperate almost twice as frequently as women paired with women.

Dynamic probability of reinforcement for cooperation: Random game termination in the centipede game.

Experimental games have previously been used to study principles of human interaction. Many such games are characterized by iterated or repeated designs that model dynamic relationships, including reciprocal cooperation. To enable the study of infinite game repetitions and to avoid endgame effects of lower cooperation toward the final game round, investigators have introduced random termination rules.

Altruism, collective rationality, and extreme self-sacrifice.

Puzzlement about extreme self-sacrifice arises from an unarticulated assumption of psychological egoism, according to which people invariably act in their own self-interests. However, altruism and collective rationality are well established experimentally: people sometimes act to benefit others or in the interests of groups to which they belong. When such social motives are sufficiently strong, extreme self-sacrifice presents no special problem of explanation and does not require out-group threats.

Correction: Social Value Induction and Cooperation in the Centipede Game.

[This corrects the article DOI: 10.1371/journal.pone.

Social Value Induction and Cooperation in the Centipede Game.

The Centipede game provides a dynamic model of cooperation and competition in repeated dyadic interactions. Two experiments investigated psychological factors driving cooperation in 20 rounds of a Centipede game with significant monetary incentives and anonymous and random re-pairing of players after every round. The main purpose of the research was to determine whether the pattern of strategic choices observed when no specific social value orientation is experimentally induced--the standard condition in all previous investigations of behavior in the Centipede and most other experimental games--is essentially individualistic, the orthodox game-theoretic assumption being that players are individualistically motivated in the absence of any specific motivational induction.

Strong Stackelberg reasoning in symmetric games: An experimental replication and extension.

In common interest games in which players are motivated to coordinate their strategies to achieve a jointly optimal outcome, orthodox game theory provides no general reason or justification for choosing the required strategies. In the simplest cases, where the optimal strategies are intuitively obvious, human decision makers generally coordinate without difficulty, but how they achieve this is poorly understood. Most theories seeking to explain strategic coordination have limited applicability, or require changes to the game specification, or introduce implausible assumptions or radical departures from fundamental game-theoretic assumptions.

The outlandish, the realistic, and the real: contextual manipulation and agent role effects in trolley problems.

Hypothetical trolley problems are widely used to elicit moral intuitions, which are employed in the development of moral theory and the psychological study of moral judgments. The scenarios used are outlandish, and some philosophers and psychologists have questioned whether the judgments made in such unrealistic and unfamiliar scenarios are a reliable basis for theory-building. We present two experiments that investigate whether differences in moral judgment due to the role of the agent, previously found in a standard trolley scenario, persist when the structure of the problem is transplanted to a more familiar context.

Spontaneous similarity discrimination in the evolution of cooperation.

The similarity discrimination effect occurs when a single gene or gene cluster causes its carriers to display both a variable phenotypic trait and a behavioural predisposition to cooperate preferentially with recognisably similar carriers. We distinguish this from the greenbeard effect, in which cooperation evolves through fixed phenotypic tags and genetically linked cooperative behaviour with others displaying the same tag. Our agent-based simulations show that the evolution of cooperation through similarity discrimination, in contrast to the greenbeard effect, does not depend on population viscosity or other restrictive conditions.

Learning to cooperate without awareness in multiplayer minimal social situations.

Experimental and Monte Carlo methods were used to test theoretical predictions about adaptive learning of cooperative responses without awareness in minimal social situations-games in which the payoffs to players depend not on their own actions but exclusively on the actions of other group members. In Experiment 1, learning occurred slowly over 200 rounds in a dyadic minimal social situation but not in multiplayer groups. In Experiments 2-4, learning occurred rarely in multiplayer groups, even when players were informed that they were interacting strategically and were allowed to communicate with one another but were not aware of the game's payoff structure.

Verbal expressions of confidence and doubt.

The development of a taxonomy of expressions expressing the degree of confidence or certainty felt in the correctness of one's judgments, knowledge, or beliefs is reported. 30 phrases expressing confidence and doubt were rated by 96 British participants on a 7-point scale to indicate how much confidence or doubt they felt each phrase expressed. The expressions were rank ordered, based on their mean ratings, to produce a continuum of cues expressing confidence, ranging from high to low.

Is luck on my side? Optimism, pessimism, and ambiguity aversion.

The influences of optimism and pessimism on ambiguity aversion were investigated in two tasks that manipulated the presence or absence of a potentially competitive experimenter. A total of 112 participants chose which option--ambiguous or known-risk--they preferred in the two slightly differing Ellsberg urns tasks. Optimism was measured using the Extended Life Orientation Test (ELOT).

Team reasoning and collective rationality: piercing the veil of obviousness.

The experiments reported in our target article provide strong evidence of collective utility maximization, and the findings suggest that team reasoning should now be included among the social value orientations used in cognitive and social psychology. Evidential decision theory offers a possible alternative explanation for our results but fails to predict intuitively compelling strategy choices in simple games with asymmetric team-reasoning outcomes. Although many of our experimental participants evidently used team reasoning, some appear to have ignored the other players' expected strategy choices and used lower-level, nonstrategic forms of reasoning.

Market entry decisions: effects of absolute and relative confidence.

In a market entry game, the number of entrants usually approaches game-theoretic equilibrium quickly, but in real-world markets business start-ups typically exceed market capacity, resulting in chronically high failure rates and suboptimal industry profits. Excessive entry has been attributed to overconfidence arising when expected payoffs depend partly on skill. In an experimental test of this hypothesis, 96 participants played 24 rounds of a market entry game, with expected payoffs dependent partly on skill on half the rounds, after their confidence was manipulated and measured.

Size doesn't really matter: ambiguity aversion in Ellsberg urns with few balls.

When attempting to draw a ball of a specified color either from an urn containing 50 red balls and 50 black balls or from an urn containing an unknown ratio of 100 red and black balls, a majority of decision makers prefer the known-risk urn, and this ambiguity aversion effect violates expected utility theory. In an experimental investigation of the effect of urn size on ambiguity aversion, 149 participants showed similar levels of aversion when choosing from urns containing 2, 10, or 100 balls. The occurrence of a substantial and significant ambiguity aversion effect even in the smallest urn suggests that influential theoretical interpretations of ambiguity aversion may need to be reconsidered.

Collective rationality in interactive decisions: evidence for team reasoning.

Decision theory and game theory rest on a fundamental assumption that players seek to maximize their individual utilities, but in some interactive decisions it seems intuitively reasonable to aim to maximize the utility of the group of players as a whole. Such team reasoning requires collective preferences and a distinctive mode of reasoning from preferences to decisions. Findings from two experiments provide evidence for collective preferences and team reasoning.

Ambiguous games: evidence for strategic ambiguity aversion.

The problem of ambiguity in games is discussed, and a class of ambiguous games is identified. A total of 195 participants played strategic-form games of various sizes with unidentified co-players. In each case, they first chose between a known-risk game involving a co-player indifferent between strategies and an equivalent ambiguous game involving one of several co-player types, each with a different dominant strategy, and then they chose a strategy for the preferred game.

Personality differences in high risk sports amateurs and instructors.

This study investigated the personality differences of 21 amateurs and 20 instructors who participated in the high risk sports of skydiving, hang-gliding, paragliding, scuba diving, microlighting, and rock climbing, versus those who did not. 38 men and 28 women (M age=32.6 yr.