Does parochial cooperation exist in childhood and adolescence? A meta-analysis

Children cooperate more with in-group members than with out-group members in an iterated face-to-face Prisoner's Dilemma Game

Adults are more likely to cooperate with in-group members than with out-group members in the context of social dilemmas, situations in which self-interest is in conflict with collective interest. This bias has the potential to profoundly shape human cooperation, and therefore it is important to understand when it emerges in development. Here we asked whether 6- to 9-year-old children (N = 146) preferentially cooperate with in-group members in the context of a well-studied social dilemma, the iterated Prisoner's Dilemma Game. We assigned children to minimal groups and paired them with unfamiliar same-age and same-gender peers. Consistent with our predictions, children were more likely to cooperate with in-group members than with out-group members in this minimal group context. This finding adds to the current literature on group bias in children's prosocial behavior by showing that it affects decision making in a context that calls on strategic cooperation. In addition, our analyses revealed an effect of gender, with girls more likely to cooperate than boys regardless of the group membership of their partner. Exploring this gender effect further, we found an interaction between gender and age across condition, with older girls showing less sensitivity to the group membership of their partner than younger girls and with older boys showing more sensitivity to the group membership of the partner than younger boys. Our findings suggest that risky cooperation in the face of social dilemmas is shaped by group bias during childhood, highlighting the potentially deeply rooted ties between cooperation and parochialism in humans.

How retributive motives shape the emergence of third-party punishment across intergroup contexts

This study examines how retributive motives-the desire to punish for the purpose of inflicting harm in the absence of future benefits-shape third-party punishment behavior across intergroup contexts. Six- to nine-year-olds (N = 151, Mage = 8.00, SDage = 1.15; 54% White, 18% mixed ethnicities, 17% Asian American; 46% female; from the USA) could punish ingroup, outgroup, or non-group transgressors by removing positive resources and allocating negative ones. Both punishments were described as retributive, yet allocating negative resources was perceived as more retributive than removing positive ones. We predicted that children would punish outgroups more so than ingroups and that this effect would be especially pronounced when punishment is perceived as particularly retributive. The results did not align with this prediction; instead, children similarly punished all agents.

Importance of Friendship and Minimal Group Membership in 4-6-Year-olds' and 9-12-Year-olds' Sharing Behavior in China

Strategies for favoring close others, such as friends and in-group members, benefit individuals and society. Although younger and older children apply these sharing strategies, how they integrate these relationships remain understudied. Friendship and group membership sometimes conflict (e.g. a friend from another, even a rival group), driving the question of how children behave in such situations. To address this question, this preregistered study recruited 121 4-6-year-olds and 94 9-12-year-olds from a middle-class community in China. A 2 (friend vs. stranger) by 2 (in vs. out-group) between-subjects design was applied per age group. Participants were asked to share seven objects with a recipient, who was either a stranger, or a previously nominated friend and from an in- or out-group (manipulated in the Minimal Group Paradigm). The results showed that children in both age groups shared more with friends than with strangers. However, only 4-6-year-olds shared more resources with in-group members than with out-group ones. Moreover, 4-6-year-olds did not distinguish between an out-group friend and an in-group stranger, while 9-12-year-olds shared more with an out-group friend relative to an ingroup stranger, indicating that friendship outweighs minimal group membership only among 9-12-year-olds. Furthermore, there was an interaction between age and minimal group membership, implying a decrease in the minimal group effect between 4-6-year-olds and 9-12-year-olds. Accordingly, the implications of friendship and minimal group effects, and their relative influence on sharing during childhood are discussed.

Group membership and adolescents' third-party punishment: a moderated chain mediation model

Third-party punishment (TPP) reflects people's social preference for fairness norms and is fundamental to maintaining fairness norms on a large scale. Several empirical studies have shown that the offender's group membership impacts TPP, but the detailed mechanisms have yet to be fully elucidated. The current study used the third-party punishment game task to explore the relationship between group membership, perceived unfairness, anger, and adolescents' TPP. A total of 306 teenagers aged 12 to 15 were chosen as subjects through cluster sampling. The results showed that group membership (classmate vs. stranger) and gender can affect adolescents' TPP together, which manifests as adolescents enacting significantly harsher punishments on strangers than on classmates, especially for boys. Group membership indirectly affects TPP through the mediating effects of perceived unfairness, anger and through a chain mediation of perceived unfairness and anger. Moreover, gender positively moderate the relationship between group membership and perceived unfairness. Specifically, group membership significantly affects boys' perceived unfairness, but cannot predict girls' perceived unfairness. The above results can be used to guide adolescents toward appropriate justice concepts and moral awareness, thus enhancing TPP.

Effects of Ingroup Identification on Ingroup Favouritism during Fairness Norm Enforcement

People tend to voluntarily sacrifice their own interests to reject unfair proposals, and this behaviour is affected by group affiliation. While group bias is a well-established phenomenon, its direction is still unclear, and little attention has been given to possible moderating factors. In two studies, we manipulate participants' ingroup identification and investigate whether and how individuals with various levels of ingroup identification react differently to unfairness from ingroups and outgroups during an incentivized (Study 1, N = 46) and hypothetical (Study 2, N = 332) ultimatum game. The results show that participants display a strong preference for their own group. High identifiers tend to accept unfair proposals from ingroups compared to outgroups, whereas this effect is nonsignificant for low identifiers, especially for moderately unfair treatment (offer 7:3). Moreover, higher identification tends to be accompanied by higher ingroup positive expectation, which then leads to greater ingroup favouritism for an offer of 7:3. These results imply that ingroup identification can enhance group favouritism during fairness norm enforcement through ingroup positive expectation.