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

- Children demonstrated a normative inclusive in-group bias.
- In-group bias was less salient in the gender compared to behavior problem contexts.
- Group functioning, identity, and stereotype reasoning was used to justify inclusion.
- The majority of children felt happy about their inclusive decisions.
- Most children attributed negative emotion to excluded out-group peers.

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 4 years (n = 59; 60% girls) and 8 years (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.