Do My Reactions Outweigh My Actions? The Relation between Reactive and Proactive Aggression with Peer Acceptance in Preschoolers.

Aggressive behaviors negatively impact peer relations starting from an early age. However, not all aggressive acts have the same underlying motivations. Reactive aggression arises as a response to an antecedent behavior of someone else, whereas proactive aggression is initiated by the aggressor and is instrumental. In this study, we aim to understand the relation between reactive and proactive aggression and peer acceptance in preschoolers. Parents of 110 children aged between 3 and 6 years old rated their children's manifestation of reactive and proactive aggressive behaviors. To assess the children's peer acceptance score within their class, they completed a paired comparisons task. The outcomes confirmed that reactive aggression in particular is negatively related to peer acceptance at the preschool age. Our results provide insights for the needs and directions of future research and interventions.

Neural processing of observed performance-based errors and rewards in the context of friends and unfamiliar peers across adolescence.

Adolescence is characterized by changes in performance monitoring, whereby action outcomes are monitored to subsequently adapt behavior and optimize performance. Observation of performance-based outcomes (i.e., errors and rewards) received by others forms the basis of observational learning. Adolescence is also a period of increasing importance of peers, especially friends, and observing peers forms a crucial aspect of learning in the social context of the classroom. However, to our knowledge, no developmental fMRI studies have examined the neural mechanisms underlying observed performance monitoring of errors and rewards in the context of peers. The current fMRI study investigated the neural correlates of observing performance-based errors and rewards of peers in adolescents aged 9-16 years (N = 80). In the scanner, participants observed either their best friend or an unfamiliar peer play a shooting game resulting in performance-dependent rewards (based on hits) or losses (based on misses, i. e, errors), where outcomes affected both the player and the observing participant. Findings showed higher activation in the bilateral striatum and bilateral anterior insula when adolescents observed peers (i.e., best friend and unfamiliar peer) receive performance-based rewards compared to losses. This might reflect the heightened salience of observed reward processing in the peer context in adolescence. Our results further revealed lower activation in the left temporoparietal junction (TPJ) while adolescents observed the performance-based outcomes (rewards and losses) for their best friend than for an unfamiliar peer. Considering that observation of others' performance-based errors and rewards forms the basis of observational learning, this study provides a crucial first step in understanding and potentially improving adolescent observational learning in the peer context.

Are there negative cycles of peer victimization and rejection sensitivity? Testing ri-CLPMs in two longitudinal samples of young adolescents.

This study's aim was to examine whether there are negative increasing cycles of peer victimization and rejection sensitivity over time. Drawing from Social Information Processing Theory, we hypothesized that victimization leads to higher levels of rejection sensitivity, which would put adolescents at risk for higher future victimization. Data were collected in a four-wave study with 233 Dutch adolescents starting secondary education (Mage = 12.7 years), and a three-wave study with 711 Australian adolescents in the last years of primary school (Mage = 10.8 years). Random-intercept cross-lagged panel models were used to disentangle between-person from within-person effects. In each sample, a significant between-person association was found: adolescents with higher levels of victimization as compared to their peers also reported higher levels of rejection sensitivity. At the within-person level, all concurrent associations between individual fluctuations of victimization and rejection sensitivity were significant, but there were no significant cross-lagged effects (except in some sensitivity analyses). These findings demonstrate that victimization and rejection sensitivity are interrelated, but there may not be negative victimization-rejection sensitivity cycles during the early-middle adolescent years. Possibly, cycles establish earlier in life or results are due to shared underlying factors. Further research is needed examining different time lags between assessments, age groups, and contexts.

Brain Responses to Peer Feedback in Social Media Are Modulated by Valence in Late Adolescence.

Previous studies have examined the neural correlates of receiving negative feedback from peers during virtual social interaction in young people. However, there is a lack of studies applying platforms adolescents use in daily life. In the present study, 92 late-adolescent participants performed a task that involved receiving positive and negative feedback to their opinions from peers in a Facebook-like platform, while brain activity was measured using functional magnetic resonance imaging (fMRI). Peer feedback was shown to activate clusters in the ventrolateral prefrontal cortex (VLPFC), medial prefrontal cortex (MPFC), superior temporal gyrus and sulcus (STG/STS), and occipital cortex (OC). Negative feedback was related to greater activity in the VLPFC, MPFC, and anterior insula than positive feedback, replicating previous findings on peer feedback and social rejection. Real-life habits of social media use did not correlate with brain responses to negative feedback.

Connecting the dots: social networks in the classroom and white matter connections in the brain.

BACKGROUND: Peer connections in school classrooms play an important role in social-emotional development and mental health. However, research on the association between children's peer relationships and white matter connections in the brain is scarce. We studied associations between peer relationships in the classroom and white matter structural connectivity in a pediatric population-based sample. METHODS: Bullying and victimization, as well as rejection and acceptance, were assessed in classrooms in 634 children at age 7. White matter microstructure (fractional anisotropy (FA), mean diffusivity (MD)) was measured with diffusion tensor imaging at age 10. We examined global metrics of white matter microstructure and used Tract-Based Spatial Statistics (TBSS) for voxel-wise associations. RESULTS: Peer victimization was associated with higher global FA and lower global MD and peer rejection was associated with lower global MD; however, these associations did not remain after multiple testing correction. Voxel-wise TBSS results for peer victimization and rejection were in line with global metrics both in terms of direction and spatial extent of the associations, with associated voxels (pFWE <.05) observed throughout the brain (including corpus callosum, corona radiata, sagittal stratum and superior longitudinal fasciculi). CONCLUSIONS: Although based only on cross-sectional data, the findings could indicate accelerated white matter microstructure maturation in certain brain areas of children who are victimized or rejected more often. However, repeated measurements are essential to unravel this complex interplay of peer connections, maturation and brain development over time.

Understanding the Dynamics of the Developing Adolescent Brain Through Team Science.

One of the major goals for research on adolescent development is to identify the optimal conditions for adolescents to grow up in a complex social world and to understand individual differences in these trajectories. Based on influential theoretical and empirical work in this field, achieving this goal requires a detailed understanding of the social context in which neural and behavioral development takes place, along with longitudinal measurements at multiple levels (e.g., genetic, hormonal, neural, behavioral). In this perspectives article, we highlight the promising role of team science in achieving this goal. To illustrate our point, we describe meso (peer relations) and micro (social learning) approaches to understand social development in adolescence as crucial aspects of adolescent mental health. Finally, we provide an overview of how our team has extended our collaborations beyond scientific partners to multiple societal partners for the purpose of informing and including policymakers, education and health professionals, as well as adolescents themselves when conducting and communicating research.

Developmental Changes in Dynamic Functional Connectivity From Childhood Into Adolescence.

The longitudinal study of typical neurodevelopment is key for understanding deviations due to specific factors, such as psychopathology. However, research utilizing repeated measurements remains scarce. Resting-state functional magnetic resonance imaging (MRI) studies have traditionally examined connectivity as 'static' during the measurement period. In contrast, dynamic approaches offer a more comprehensive representation of functional connectivity by allowing for different connectivity configurations (time varying connectivity) throughout the scanning session. Our objective was to characterize the longitudinal developmental changes in dynamic functional connectivity in a population-based pediatric sample. Resting-state MRI data were acquired at the ages of 10 (range 8-to-12, n = 3,327) and 14 (range 13-to-15, n = 2,404) years old using a single, study-dedicated 3 Tesla scanner. A fully-automated spatially constrained group-independent component analysis (ICA) was applied to decompose multi-subject resting-state data into functionally homogeneous regions. Dynamic functional network connectivity (FNC) between all ICA time courses were computed using a tapered sliding window approach. We used a k-means algorithm to cluster the resulting dynamic FNC windows from each scan session into five dynamic states. We examined age and sex associations using linear mixed-effects models. First, independent from the dynamic states, we found a general increase in the temporal variability of the connections between intrinsic connectivity networks with increasing age. Second, when examining the clusters of dynamic FNC windows, we observed that the time spent in less modularized states, with low intra- and inter-network connectivity, decreased with age. Third, the number of transitions between states also decreased with age. Finally, compared to boys, girls showed a more mature pattern of dynamic brain connectivity, indicated by more time spent in a highly modularized state, less time spent in specific states that are frequently observed at a younger age, and a lower number of transitions between states. This longitudinal population-based study demonstrates age-related maturation in dynamic intrinsic neural activity from childhood into adolescence and offers a meaningful baseline for comparison with deviations from typical development. Given that several behavioral and cognitive processes also show marked changes through childhood and adolescence, dynamic functional connectivity should also be explored as a potential neurobiological determinant of such changes.

Integrating Cognitive Developmental Neuroscience in Society: Lessons Learned From a Multidisciplinary Research Project on Education and Social Safety of Youth.

Integrating fundamental science in society, with the goal to translate research findings to daily practice, comes with certain challenges. Successfully integrating research projects into society requires (1) good collaboration between scientists and societal stakeholders, (2) collaboration partners with common expectations and goals, and (3) investment in clear communication. Here we describe an integrative research project conducted by a large Dutch consortium that consisted of neuroscientists, psychologists, sociologists, ethicists, teachers, health care professionals and policy makers, focusing on applying cognitive developmental neuroscience for the benefit of youth in education and social safety. We argue that to effectively integrate cognitive developmental neuroscience in society, (1) it is necessary to invest in a well-functioning, diverse and multidisciplinary team involving societal stakeholders and youth themselves from the start of the project. This aids to build a so-called productive interactive network that increases the chances to realize societal impact in the long-term. Additionally, we propose that to integrate knowledge, (2) a different than standard research approach should be taken. When focusing on integration, the ultimate goal of research is not solely to understand the world better, but also to intervene with real-life situations, such as education or (forensic) youth care. To accomplish this goal, we propose an approach in which integration is not only started after the research has been conducted, but taken into account throughout the entire project. This approach helps to create common expectations and goals between different stakeholders. Finally, we argue that (3) dedicating sufficient resources to effective communication, both within the consortium and between scientists and society, greatly benefits the integration of cognitive developmental neuroscience in society.

Parental Support and Positive Mood Buffer Adolescents' Academic Motivation During the COVID-19 Pandemic.

School closures during the first COVID-19 lockdown in 2020 severely disrupted adolescents' lives. We used a daily diary method for 20 days, including online and physical school days, assessing daily mood, social support and conflict, and academic motivation in 102 adolescents aged 12-16 years. We found that adolescents' academic motivation was lower on online compared with physical school days. In general, positive mood was positively associated with academic motivation, and friend conflict related negatively to academic motivation. Moreover, lower levels of parental support were related to lower academic motivation on online versus physical school days. Overall, these findings identified some critical changes in adolescents' daily experiences during the COVID-19 school closure and social-emotional factors that may buffer decreases in adolescents' academic motivation.

Happy for Us not Them: Differences in neural activation in a vicarious reward task between family and strangers during adolescent development.

During adolescence social-interactions with other people become more relevant. One key aspect of these interactions is cooperative behavior. Cooperation relies on a set of cognitive and affective mechanisms. In this study, we focused on the mental ability to feel happy for another person's positive experience, called vicarious joy. We investigated the neural mechanisms of this ability using a false-choice vicarious reward fMRI task. Participants played a game where they could win monetary rewards for themselves, their mother, their father, and a stranger. A region-of-interest (ROI) analysis of the Nucleus Accumbens revealed robust activation in this region for personal reward as well as vicarious rewards for both parents. Vicarious reward for a stranger was not associated with activation within the Nucleus Accumbens. ROI activation was associated with self-reported vicarious joy for mother and father. A Prisoner's Dilemma game outside the scanner showed an increase in cooperative behavior until age 14 for parents and strangers, followed by a decline for the stranger but not for the parents. Together, these findings demonstrate that adolescence is an important time for developing ingroup-outgroup relations.

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 motivations related to formation and maintenance of friendships across adolescence.

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 biannual 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), temporoparietal 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.

I am happy for us: Neural processing of vicarious joy when winning for parents versus strangers.

This study investigated the neural processes underlying vicarious joy and their dependence on emotional closeness. Prior studies revealed that the nucleus accumbens (NAcc) is a target brain region for processing rewards for self, but the neural mechanisms of processing rewards for others are not yet well understood. A functional magnetic resonance imaging (fMRI) paradigm was employed in young adults (N = 30), in combination with a self-report questionnaire on the perceived emotional closeness to the target. We examined the neural correlates of vicarious rewards when winning money for oneself or one of three other targets. To examine family relationships, two of the targets were the mother and father of the participants, and the third target was an unknown stranger. We found an increase in activation in the NAcc when playing for family members compared with a stranger. We further observed a difference in neural activation when winning for the father compared with the mother in an extended network involving the medial prefrontal cortex and precuneus, brain regions involved in mentalizing. These findings were not related to reports of emotional closeness. This new paradigm has considerable value for future research into the fundamental neural processes underlying empathy and vicarious joy.

Developmental Changes and Individual Differences in Trust and Reciprocity in Adolescence.

A Trust Game was used to examine trust and reciprocity development in 12-18-year-old-adolescents (N = 496), as findings have been conflicting and transitions in adolescence remain elusive. Furthermore, this study tested the roles of gender, risk, and individual differences in empathy, impulsivity, and antisocial tendencies in trust and reciprocity. Results indicate stability in trust and a decrease in reciprocity across adolescence, but also show that trust and reciprocity choices were influenced by risk, and that empathy mediated the age-related decrease in reciprocity. Males trusted more than females, but there were no gender differences in reciprocity. These findings highlight the importance of considering individual differences and adolescents' sensitivities to varying contexts in explaining trust and reciprocity development in adolescence.

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 = 2,381). High-resolution structural MRI was conducted when children were 10 years of age. Cortical thickness estimates across the cortical mantle were compared among groups. Results: Children classified as frequent targets of bullying showed thicker cortex in the fusiform gyrus compared to those uninvolved in bullying (B = 0.108, p corrected < 0.001). Results remained consistent when adjusted for socioeconomic factors, general intelligence, and psychiatric symptoms. Children classified as frequent perpetrators showed thinner cortex in the cuneus region; however, this association did not survive stringent correction for multiple testing. Lastly, no differences in cortical thickness were observed in perpetrator-targets. Discussion: Bullying involvement in young children was associated with differential cortical morphology. Specifically, the fusiform gyrus, often involved in facial processing, showed thicker cortex in targets of frequent bullying. Longitudinal data are necessary to demonstrate the temporality of the underlying neurobiology associated with bullying involvement.

Friends and foes: Neural correlates of prosocial decisions with peers in adolescence.

Adolescence is a critical period for social orientation to peers and for developing social skills in interactions with peers. In the current study we examined the neural correlates of prosocial decisions for friends and disliked peers, and their links with participants' friendship quality and empathy as indices of social competence. Participants' friends and disliked peers were identified using sociometric nominations. Mid-adolescents (Mage = 14.6; N = 50) distributed coins between themselves and another player in a set of allocation games where they could make prosocial or selfish decisions for their friends and disliked peers, as well as for neutral and unfamiliar peers. Participants made the most prosocial decisions for friends and the least prosocial decisions for disliked peers. Prosocial decisions for friends yielded activity in the putamen and posterior middle temporal gyrus (pMTG) when compared to prosocial decisions for disliked peers, and in the superior parietal lobule (SPL) and precentral gyrus when compared to prosocial decisions for unfamiliar peers. Selfish decisions for friends and decisions for disliked peers did not result in heightened neural activity. Exploratory analyses of the associations between these neural activation patterns and measures of social competence revealed that putamen activity related negatively to negative friendship quality and that empathic personal distress related positively to SPL and precentral gyrus activity. Together, the findings illustrated that the SPL, precentral gyrus, pMTG, and putamen may be involved in promoting the continuation of friendships, and that social competence may modulate these neural mechanisms.

Turning a Blind Eye? Punishment of Friends and Unfamiliar Peers After Observed Exclusion in Adolescence.

In order to decrease the occurrence of social exclusion in adolescence, we need to better understand how adolescents perceive and behave toward peers involved in exclusion. We examined the role of friendships in treatment of perpetrators and victims of social exclusion. Eighty-nine participants (aged 9-16) observed exclusion of an unfamiliar peer (victim) by their best friend and another unfamiliar peer. Subsequently, participants could give up valuable coins to altruistically punish or help peers. Results showed that participants altruistically compensated victims and punished unfamiliar excluders, but refrained from punishing their friends. Our findings show that friendship with excluders modulates altruistic punishment of peers and provide mechanistic insight into how friendships may influence treatment of peers involved in social exclusion during adolescence.

What lies beneath peer acceptance in adolescence? Exploring the role of Nucleus Accumbens responsivity to self-serving and vicarious rewards.

Peer relationships play an important role in adolescent social development. Adolescence is also a sensitive period for reward-related processing where Nucleus Accumbens (NAcc) shows peak levels of activity. To investigate the role of reward-related neural processes in peer relationships, we scanned 31 adolescents (16 boys, 15 girls) from 12 to 17 years old and had their classmates rate their likability and dislikability. Using these ratings, we calculated levels of peer acceptance (i.e., likability minus dislikability scores). Participants played a social gambling paradigm in the scanner where we examined NAcc responses to winning for self and winning for best friends. We showed that acceptance by peers was related negatively to activation patterns in the NAcc when winning money for self. Peer acceptance was not related to NAcc activity during vicarious reward processing where participants won money for their best friend. These results point in the direction of an underlying neural mechanism indicating that peer interactions of well-liked adolescents are characterized by a lower focus on benefits for self.

Social network cohesion in school classes promotes prosocial behavior.

Adolescence is a key period of social development at the end of which individuals are expected to take on adult social roles. The school class, as the most salient peer group, becomes the prime environment that impacts social development during adolescence. Using social network analyses, we investigated how individual and group level features are related to prosocial behavior and social capital (generalized trust). We mapped the social networks within 22 classrooms of adolescents aged between 12 and 18 years (N = 611), and collected data on social behaviors towards peers. Our results indicate that individuals with high centrality show both higher levels of prosocial behavior and relational aggression. Importantly, greater social cohesion in the classroom was associated with (1) reduced levels of antisocial behavior towards peers and (2) increased generalized trust. These results provide novel insights in the relationship between social structure and social behavior, and stress the importance of the school environment in the development of not only intellectual but also social capital.

Contributions of Reward Sensitivity to Ventral Striatum Activity Across Adolescence and Early Adulthood.

It was examined how ventral striatum responses to rewards develop across adolescence and early adulthood and how individual differences in state- and trait-level reward sensitivity are related to these changes. Participants (aged 8-29 years) were tested across three waves separated by 2 years (693 functional MRI scans) in an accelerated longitudinal design. The results confirmed an adolescent peak in reward-related ventral striatum, specifically nucleus accumbens, activity. In early to mid-adolescence, increases in reward activation were related to trait-level reward drive. In mid-adolescence to early adulthood decreases in reward activation were related to decreases in state-level hedonic reward pleasure. This study demonstrates that state- and trait-level reward sensitivity account for reward-related ventral striatum activity in different phases of adolescence and early adulthood.