Discriminatory punishment undermines the enforcement of group cooperation.

Peer punishment can help groups to establish collectively beneficial public goods. However, when humans condition punishment on other factors than poor contribution, punishment can become ineffective and group cooperation deteriorates. Here we show that this happens in pluriform groups where members have different socio-demographic characteristics. In our public good provision experiment, participants were confronted with a public good from which all group members benefitted equally, and in-between rounds they could punish each other. Groups were uniform (members shared the same academic background) or pluriform (half the members shared the same academic background, and the other half shared another background). We show that punishment effectively enforced cooperation in uniform groups where punishment was conditioned on poor contribution. In pluriform groups, punishment was conditioned on poor contribution too, but also partially on others' social-demographic characteristics-dissimilar others were punished more than similar others regardless of their contribution. As a result, punishment lost its effectiveness in deterring free-riding and maintaining public good provision. Follow-up experiments indicated that such discriminatory punishment was used to demarcate and reinforce subgroup boundaries. This work reveals that peer punishment fails to enforce cooperation in groups with a pluriform structure, which is rule rather than exception in contemporary societies.

The Detrimental Effects of No Trust: Active Decisions of No Trust Cause Stronger Affective and Behavioral Reactions Than Inactive Decisions.

In two experimental studies, we investigated the affective (Studies 1 and 2) and behavioral (Study 2) effects of not being trusted. In an adapted version of the Trust Game paradigm, participants were all assigned the position of Person B, and learned that their opponent (Person A) had decided to not let them divide monetary outcomes. This had either been an inactive decision (Person A had not offered them the option to distribute outcomes) or an active decision (Person A had taken away their option to distribute outcomes). Results of both studies reveal that reactions to not being trusted were significantly affected by whether this decision was active or inactive. Active decisions evoked a more negative evaluation toward Person A, led participants to experience more negative emotions, and lowered their satisfaction with the final outcome, even though payoffs and final earnings were held constant between the conditions (Study 1). In addition, when the decision not to trust had been an active decision, participants subsequently behaved less altruistic, as evidenced by significant lower allocations in a subsequent Dictator Game (Study 2). Interestingly, this reduction in altruism was not restricted to encounters with Person A, but also extended to an uninvolved other (Person C).

The emergence of conventions in the repeated volunteer's dilemma: The role of social value orientation, payoff asymmetries and focal points.

Conventions are arbitrary rules of behavior that coordinate social interactions. Here we study the effects of individuals' social value orientations (SVO) and situational conditions on the emergence of conventions in the three-person volunteer's dilemma (VOD). The VOD is a step-level collective good game in which only one actor's action is required to produce a benefit for the group. It has been shown that if actors interact in the payoff-symmetric VOD repeatedly, a turn-taking convention emerges, resulting in an equal distribution of payoffs. If the VOD is asymmetric, with one "strong" actor having lower costs of volunteering, a solitary-volunteering convention emerges by which the strong actor volunteers earning less than others. In study 1 we test whether SVO promotes turn-taking and hampers solitary-volunteering. We find that groups with more prosocials engage less in turn-taking and no effect of SVO on the emergence of solitary-volunteering. In study 2 we test whether making one actor focal is sufficient for solitary-volunteering to emerge. We find instead that payoff asymmetry with one strong actor is a necessary precondition. We discuss explanations for our findings and propose directions for future research.

Preferences for cervical cancer screening: The role of implicit associations.

OBJECTIVES: Implicit associations influence behaviour, but their impact on cancer screening intentions is unknown. METHODS: We assessed implicit associations with cervical cancer screening using an evaluative priming task. Participants were shown primes ('Pap test', neutral or non-word) followed by positive or negative target words. The test is based on the assumption that response times are shorter if primes and targets are strongly associated in the participant's mind. The Dutch screening program targets women aged 30-60, 226 of them completed online assessments twice. Prior to the second assessment participants were randomized to reading versus not reading the leaflet about the cervical screening program. RESULTS: After controlling for knowledge and screen history, response times for 'Pap test' no longer differed between positive and negative targets. Implicit associations were not correlated with explicit attitudes or screening intentions. Reading the screening leaflet resulted in improved knowledge levels (p<0.001), but implicit associations, explicit attitudes, and screening intentions remained similar. CONCLUSION: Cervical cancer screening intentions were related to explicit attitudes, but not to implicit associations. The screening leaflet did not affect screening intentions. PRACTICE IMPLICATIONS: We recommend achieving a deepened interest in the screening program among risk groups, e.g. by adapting the information leaflet.

Increasing interpersonal trust through divergent thinking.

Interpersonal trust is an essential ingredient of many social relationships but how stable is it actually, and how is it controlled? There is evidence that the degree of trust into others might be rather volatile and can be affected by manipulations like drawing attention to personal interdependence or independence. Here we investigated whether the degree of interpersonal trust can be biased by inducing either a more integrative or a more focused/exclusive cognitive control mode by means of a creativity task requiring divergent or convergent thinking, respectively. Participants then performed the trust game, which provides an index of interpersonal trust by assessing the money units one participant (the trustor) transfers to another (the trustee). As expected, trustors transferred significantly more money to trustees after engaging in divergent thinking as compared to convergent thinking. This observation provides support for the idea that interpersonal trust is controlled by domain-general (i.e., not socially dedicated) cognitive states.

Anger and retribution after collective overuse: the role of blaming and environmental uncertainty in social dilemmas.

This article investigates how group members respond to one another when collective overuse occurs. The authors argue that interpersonal reactions after overuse in a common-resource dilemma are largely determined by the environmental characteristics of the social dilemma. More specifically, under environmental certainty they expect people to show more anger to group members than under uncertainty (Study 1). Additionally, they expect stronger retributive reactions to high harvesters than to moderate harvesters, and they expect this difference to be larger under certainty than under uncertainty (Study 2 and 3). Moreover, they predict that these effects are mediated by blaming. The results of three experiments corroborate these predictions.

Tacit coordination in social dilemmas: the importance of having a common understanding.

Previous research has indicated that in social dilemmas, people tacitly coordinate their decisions by using the equal division rule. In 3 experimental studies, the authors investigated the extent to which a common understanding about task and behavioral requirements is essential for the tacit coordination process. The results show that people are less likely to coordinate on the equal division rule when collective feedback on past performance (Study 1), the distribution of information within the group (Study 2), or expected behavioral variance (Study 3) suggests that a common understanding in the group is lacking. Moreover, the results indicate that under these conditions, rather than adhering to the equal division rule, people base their decisions on their own social value orientations. The findings support the view that if situations provide insufficient cues for tacit coordination, people are more likely to decide on the basis of their personal characteristics.

Justifying decisions in social dilemmas: justification pressures and tacit coordination under environmental uncertainty.

This article investigates how justification pressures influence harvesting decisions in common resource dilemmas. The authors argue that when a division rule prescribes a specific harvest level, such as under environmental certainty, people adhere more strongly to this division rule when they have to justify their decisions to fellow group members. When a division rule does not prescribe a specific harvest level, such as under environmental uncertainty, people restrict their harvests when they have to justify their decisions to fellow group members. The results of two experimental studies corroborate this line of reasoning. The findings are discussed in terms of tacit coordination. The authors specify conditions under which justification pressures may or may not facilitate efficient coordination.