"Only you can play with me!" Children's inclusive decision making, reasoning, and emotions based on peers' gender and behavior problems.

This study examined the development of children's decisions, reasoning, and emotions in contexts of peer inclusion/exclusion. We asked an ethnically diverse sample of 117 children aged 4years (n=59; 60% girls) and 8years (n=58; 49% girls) to choose between including hypothetical peers of the same or opposite gender and with or without attention deficit/hyperactivity problems and aggressive behavior. Children also provided justifications for, and emotions associated with, their inclusion decisions. Both 4- and 8-year-olds predominantly chose to include the in-group peer (i.e., the same-gender peer and peers without behavior problems), thereby demonstrating a normative in-group inclusive bias. Nevertheless, children included the out-group peer more in the gender context than in the behavior problem contexts. The majority of children reported group functioning-related, group identity-related, and stereotype-related reasoning after their in-group inclusion decisions, and they associated happy feelings with such decisions. Although most children attributed sadness to the excluded out-group peer, they attributed more anger to the excluded out-group peer in the aggression context compared with other contexts. We discuss the implications of our findings for current theorizing about children's social-cognitive and emotional development in contexts of peer inclusion and exclusion.