Participants (N = 384 three- to ten-year-olds; 51% girls, 49% boys; 73% White, 18% multiracial/other, 5% Asian, and 3% Black; N = 610 adults) saw depictions of 20 individuals split into two social groups (1:19; 2:18; 5:15; or 8:12 per group) and selected which group was "in charge" (Experiment 1), "the leader" (Experiment 2),…

Strategic collaboration according to the law of comparative advantage involves dividing tasks based on the relative capabilities of group members. Three experiments (N = 405, primarily White and Asian, 45% female, collected 2016-2019 in Canada) examined how this strategy develops in children when dividing cognitive labor. Children divided…

This study investigates the dynamic interplay between bullying relationships and friendships in a sample of 481 students in 19 elementary school classrooms (age 8-12 years; 50% boys). Based on a relational framework, it is to be expected that friendships would be formed when two children bullied the same person and that children would start to…

M. Tomasello, A. Kruger, and H. Ratner (1993) proposed a theory of cultural learning comprising imitative learning, instructed learning, and collaborative learning. Empirical and theoretical advances in the past 20 years suggest modifications to the theory; for example, children do not just imitate but overimitate in order to identify and…

This study examined the value of using a group-centered approach to evaluate process quality of early childhood education and care (ECEC). Is observed support of group processes a different aspect of classroom quality, and does it predict children's collaborative play in ECEC in the Netherlands? In two play situations, 37 teachers and 120 two- to…

This study examined factors that predicted children's gender intergroup attitudes at age 5 and the implications of these attitudes for intergroup behavior. Ethnically diverse children from low-income backgrounds (N = 246; Mexican-, Chinese-, Dominican-, and African American) were assessed at ages 4 and 5. On average, children reported positive…

Three experiments ("N" = 130) used a minimal group manipulation to show that just perceived membership in a social group boosts young children's motivation for and learning from group-relevant tasks. In Experiment 1, 4-year-old children assigned to a minimal "puzzles group" persisted longer on a challenging puzzle than children identified as the…

Does children's bias toward their own groups reflect egocentrism or social understanding? After being categorized as belonging to 1 of 2 fictitious groups, 157 six- to ten-year-olds evaluated group members and expressed preferences among neutral items. Children who expected the in-group to share their item preferences (egocentric social…

Exclusion and victimization by classmates were related to levels and diurnal change in cortisol in 97 fourth graders (53% boys, M = 9.3 years). Number and quality of friendships were considered as moderators. Salivary cortisol was collected 5 times daily on 2 school days. Excluded children had elevated cortisol levels at school and a flattened…

Children and adolescents evaluated group inclusion and exclusion in the context of generic and group-specific norms involving morality and social conventions. Participants ("N" = 381), aged 9.5 and 13.5 years, judged an in-group member's decision to deviate from the norms of the group, whom to include, and whether their personal…

In Study 1, 167 English children aged 6-8 or 9-11 evaluated peer English or French soccer fans that were loyal or partially disloyal. In Study 2, 149 children aged 5-11 made judgments about generic inclusion norms between and within competitive groups. In both studies, children's understanding of intergroup inclusion/exclusion norms (group nous)…

The developmental model of subjective group dynamics hypothesizes that peer exclusion during middle childhood involves inferences about group dynamics. To test the generality of this prediction, children judged, within minimal groups, peers whose behavior was loyal versus disloyal (Study 1: n = 46, mean age = 113 months) or morally acceptable…

Interpersonal dynamics within friendships were observed in a sample of 120 (60 male, 60 female) ethnically diverse 16- and 17-year-old adolescents characterized as persistently antisocial, adolescent-onset, and normative. Dyadic mutuality and deviant talk were coded from videotaped friendship interactions. Persistently antisocial adolescents…

This study interconnects developmental psychology of fair and moral behavior with economic game theory. One hundred eighty-nine 9- to 17-year-old students shared a sum of money as individuals and groups with another anonymous group (dictator game). Individual allocations did not differ by age but did by gender and were predicted by participants'…

Tested hypothesis that children would compete more playing competitive games in tetrads than in dyads. Found that male target children competed more in tetrads than in dyads; female target children did not show different levels of competition based on group size. Based on a global measure of smiling, the emotional atmosphere was less positive in…