The effect of intergroup competition on group coordination: An experimental study

We report an experiment on the effect of intergroup competition on group coordination in the minimal-effort game (Van Huyck et al., 1990). The competition was between two 7-person groups. Each player in each group independently chose an integer from 1 to 7. The group with the higher minimum won the competition and each of its members was paid according to the game’s original payoff matrix. Members of the losing group were paid nothing. In case of a tie, each player was paid half the payoff in the original matrix. This treatment was contrasted with two control treatments where each of the two groups played an independent coordination game, either with or without information about the minimum chosen by the outgroup. Although the intergroup competition does not change the set of strict equilibria, we found that it improved collective rationality by moving group members in the direction of higher-payoff equilibria. Merely providing group members with information about the minimal-effort level in the other group was not sufficient to generate this effect.Non cooperative games, coordination, minimum effort game, intergroup competition, Leex

The psychological impact of dependency in adults withchronic fatigue syndrome/myalgic encephalomyelitis: A qualitative exploration

Chronic fatigue syndrome/myalgic encephalomyelitis can limit functional capacity, producing various degrees of disability and psychological distress. Semi-structured interviews explored the experiences of adults with chronic fatigue syndrome/myalgic encephalomyelitis being physically dependent on other people for help in daily life, and whether physical dependency affects their psychological well-being. Thematic analysis generated six themes: loss of independence and self-identity, an invisible illness, anxieties of today and the future, catch-22, internalised anger, and acceptance of the condition. The findings provide insight into the psychological impact of dependency. Implications for intervention include better education relating to chronic fatigue syndrome/myalgic encephalomyelitis for family members, carers, and friends; ways to communicate their needs to others who may not understand chronic fatigue syndrome/myalgic encephalomyelitis; and awareness that acceptance of the condition could improve psychological well-being

Group Polarization in the Team Dictator Game reconsidered

While most papers on team decision-making find teams to behave more selfish, less trusting and less altruistic than individuals, Cason and Mui (1997) report that teams are more altruistic than individuals in a dictator game. Using a within-subjects design we re-examine group polarization by letting subjects make individual as well as team decisions in an experimental dictator game. In our experiment teams are more selfish than individuals, and the most selfish team member has the strongest influence on team decisions. Various sources of the different findings in Cason and Mui (1997) and in our paper are discussed

High-resolution fMRI of content-sensitive subsequent memory responses in human medial temporal lobe

Abstract & The essential role of the medial temporal lobe (MTL) in long-term memory for individual events is well established, yet important questions remain regarding the mnemonic functions of the component structures that constitute the region. Within the hippocampus, recent functional neuroimaging findings suggest that formation of new memories depends on the dentate gyrus and the CA 3 field, whereas the contribution of the subiculum may be limited to retrieval. During encoding, it has been further hypothesized that structures within MTL cortex contribute to encoding in a content-sensitive manner, whereas hippocampal structures may contribute to encoding in a more domain-general manner. In the current experiment, highresolution fMRI techniques were utilized to assess novelty and subsequent memory effects in MTL subregions for two classes of stimuli-faces and scenes. During scanning, participants performed an incidental encoding (target detection) task with novel and repeated faces and scenes. Subsequent recognition memory was indexed for the novel stimuli encountered during scanning. Analyses revealed voxels sensitive to both novel faces and novel scenes in all MTL regions. However, similar percentages of voxels were sensitive to novel faces and scenes in perirhinal cortex, entorhinal cortex, and a combined region comprising the dentate gyrus, CA 2 , and CA 3 , whereas parahippocampal cortex, CA 1 , and subiculum demonstrated greater sensitivity to novel scene stimuli. Paralleling these findings, subsequent memory effects in perirhinal cortex were observed for both faces and scenes, with the magnitude of encoding activation being related to later memory strength, as indexed by a graded response tracking recognition confidence, whereas subsequent memory effects were scene-selective in parahippocampal cortex. Within the hippocampus, encoding activation in the subiculum correlated with subsequent memory for both stimulus classes, with the magnitude of encoding activation varying in a graded manner with later memory strength. Collectively, these findings suggest a gradient of content sensitivity from posterior (parahippocampal) to anterior (perirhinal) MTL cortex, with MTL cortical regions differentially contributing to successful encoding based on event content. In contrast to recent suggestions, the present data further indicate that the subiculum may contribute to successful encoding irrespective of event content. &amp

Identities, selection, and contributions in a public-goods game

The notions of one's social identity and group membership have recently become topics for economic theory and experiments, and recent research has shown the importance of identity in a wide array of economic environments. But predictions are unclear when there is some trade-off between one's identity (e.g., race, gender, handedness) and potential monetary considerations. We conduct a public-goods experiment in which we permit endogenous group-formation. In a 2x2 design, we vary whether people participate in a team-building exercise and whether some people receive an endowment twice as much as others receive. We find that when both identity and financial considerations are present, high-endowment participants are strongly attracted to each other, with one's word-task-group affiliation eclipsed by the opportunity to earn more. Nevertheless, the team-building exercise greatly increases the level of contribution whether or not one is linked to people from one's team-building exercise

Rivaroxaban for secondary stroke prevention in patients with embolic strokes of undetermined source : Design of the NAVIGATE ESUS randomized trial

Peer reviewe

Avpr1a variant associated with preschoolers' lower altruistic behavior

10.1371/journal.pone.0025274PLoS ONE69