Longitudinal links between childhood peer acceptance and the neural correlates of sharing

Childhood peer acceptance is associated with high levels of prosocial behavior and advanced perspective taking skills. Yet, the neurobiological mechanisms underlying these associations have not been studied. This functional magnetic resonance imaging study examined the neural correlates of sharing decisions in a group of adolescents who had a stable accepted status (n = 27) and a group who had a chronic rejected status (n = 19) across six elementary school grades. Both groups of adolescents played three allocation games in which they could share money with strangers with varying costs and profits to them and the other person. Stably accepted adolescents were more likely to share their money with unknown others than chronically rejected adolescents when sharing was not costly. Neuroimaging analyses showed that stably accepted adolescents, compared to chronically rejected adolescents, exhibited higher levels of activation in the temporo-parietal junction, posterior superior temporal sulcus, temporal pole, pre-supplementary motor area, and anterior insula during costly sharing decisions. These findings demonstrate that stable peer acceptance across childhood is associated with heightened activity in brain regions previously linked to perspective taking and the detection of social norm violations during adolescence, and thereby provide insight into processes underlying the widely established links between peer acceptance and prosocial behavior

Friendship stability in adolescence is associated with ventral striatum responses to vicarious rewards

An important task for adolescents is to form and maintain friendships. In this three-wave biannual study, we used a longitudinal neuroscience perspective to examine the dynamics of friendship stability. Relative to childhood and adulthood, adolescence is marked by elevated ventral striatum activity when gaining self-serving rewards. Using a sample of participants between the ages of eight and twenty-eight, we tested age-related changes in ventral striatum response to gaining for stable (n = 48) versus unstable best friends (n = 75) (and self). In participants with stable friendships, we observed a quadratic developmental trajectory of ventral striatum responses to winning versus losing rewards for friends, whereas participants with unstable best friends showed no age-related changes. Ventral striatum activity in response to winning versus losing for friends further varied with friendship closeness for participants with unstable friendships. We suggest that these findings may reflect changing social motivati

Beyond the Average Brain: Individual Differences in Social Brain Development are Associated with Friendship Quality

We tested whether adolescents differ from each other in the structural development of the social brain, and whether individual differences in social brain development predicted variability in friendship quality development. Adolescents (N = 299, Mage T1 = 13.98 years) were followed across three bi-annual waves. We analysed self-reported friendship quality with the best friend at T1 and T3, and bilateral measures of surface area and cortical thickness of the medial prefrontal cortex (mPFC), posterior superior temporal sulcus (pSTS), temporo-parietal junction (TPJ), and precuneus across all waves. At the group level, growth curve models confirmed non-linear decreases of surface area and cortical thickness in social brain regions. We identified substantial individual differences in levels and change rates of social brain regions, especially for surface area of the mPFC, pSTS, and TPJ. Change rates of cortical thickness varied less between persons. Higher levels of mPFC surface area and cortical thickness predicted stronger increases in friendship quality over time. Moreover, faster cortical thinning of mPFC surface area predicted a stronger increase in friendship quality. Higher levels of TPJ cortical thickness predicted lower friendship quality. Together, our results indicate heterogeneity in social brain development and how this variability uniquely predicts friendship quality development

Friend versus foe: Neural correlates of prosocial decisions for liked and disliked peers

Although the majority of our social interactions are with people we know, few studies have investigated the neural correlates of sharing valuable resources with familiar others. Using an ecologically valid research paradigm, this functional magnetic resonance imaging study examined the neural correlates of prosocial and selfish behavior in interactions with real-life friends and disliked peers in young adults. Participants (N = 27) distributed coins between themselves and another person, where they could make selfish choices that maximized their own gains or prosocial choices that maximized outcomes of the other. Participants were more prosocial toward friends and more selfish toward disliked peers. Individual prosociality levels toward friends were associated negatively with supplementary motor area and anterior insula activity. Further preliminary analyses showed that prosocial decisions involving friends were associated with heightened activity in the bilateral posterior temporoparietal junction, and selfish decisions involving disliked peers were associated with heightened superior temporal sulcus activity, which are brain regions consistently shown to be involved in mentalizing and perspective taking in prior studies. Further, activation of the putamen was observed during prosocial choices involving friends and selfish choices involving disliked peers. These findings provide insights into the modulation of neural processes that underlie prosocial behavior as a function of a positive or negative relationship with the interaction partner

Frequent bullying involvement and brain morphology in children

Background: Over the past few decades, bullying has been recognized as a considerable public health concern. Involvement in bullying is associated with poor long-term social and psychiatric outcomes for both perpetrators and targets of bullying. Despite this concerning prognosis, few studies have investigated possible neurobiological correlates of bullying involvement that may explain the long-term impact of bullying. Cortical thickness is ideally suited for examining deviations in typical brain development, as it has been shown to detect subtle differences in children with psychopathology. We tested associations between bullying involvement and cortical thickness using a large, population-based cohort. Methods: The study sample consisted of 2,602 participants from the Generation R Study. When children were 8 years old, parents and teachers reported on common forms of child bullying involvement (physical, verbal, and relational). Questions ascertained whether a child was involved as a perpetrator (n = 82), a target of bullying (n = 92), as a combined perpetrator and target of bullying (n = 47), or uninvolved in frequent bullying (n = 2,38

Disentangling proactive and reactive aggression in children using self-report

The distinction between proactive and reactive functions of aggression is one of the most common divisions when investigating aggression among children and adolescents. To date, self-report is the least used measurement, despite existing literature supporting the view that the best informant regarding internal processes and motives are children themselves. The main aim of this study was to examine the construct and concurrent validity of a new self-report questionnaire, which aims to disentangle acts of reactive vs. proactive aggression that are most common within the daily lives of children. We examined the self-report measure among 578 children (313 girls, 265 boys, mean age 11 years, range 9–13 years). Most children (90% boys; 85% girls) reported at least one act of aggression over the last four weeks. Furthermore, the outcomes support the two-factor structure (reactive and proactive aggression) and the questionnaire showed good concurrent and discriminant validity with measures for emotional and social functioning. This study validates the use of the self-report instrument for reactive and proactive aggression and demonstrates that children can successfully distinguish between their own motives for reactive and proactive forms of aggressive behaviours