Gene-Environment Correlation Linking Aggression and Peer Victimization: Do Classroom Behavioral Norms Matter?

Peer Victimization and Callous-Unemotional Traits: The Impact of Parents and Teachers

Research on the link between peer victimization and callous-unemotional (CU) traits has primarily relied on cross-sectional designs and yielded equivocal findings. In light of the poor outcomes related to peer victimization and CU traits, it is important to determine whether this link is reciprocal in nature and to identify factors that may influence its strength. Accordingly, the current study investigated the bidirectional association between peer victimization and CU traits over a 6-month period, accounting for the moderating effects of parents (i.e., support and hostility) and teachers (i.e., support and conflict). Participants included 284 third- through fifth-grade students (ages 7-12; 51.8% boys; 51.1% Hispanic) and their homeroom teachers. Children provided ratings of peer victimization, parental hostility, and parent and teacher support. Teachers provided ratings of CU traits and student-teacher conflict. A series of cross-lagged panel models were estimated. Results revealed that, at higher levels of parental hostility, peer victimization predicted increases in CU traits over time; in contrast, peer victimization predicted decreases in CU traits at lower levels of parental hostility. Surprisingly, at higher levels of teacher conflict, peer victimization predicted decreases in CU traits over time. CU traits did not interact with parent or teacher variables to predict subsequent peer victimization. Moreover, parental hostility was positively associated with subsequent peer victimization, whereas teacher support predicted decreases in victimization over time. These findings build on previous research examining environmental influences on the expression of CU traits by highlighting peer victimization and parental hostility as potential risk factors.

Are victims of bullying primarily social outcasts? Person-group dissimilarities in relational, socio-behavioral, and physical characteristics as predictors of victimization

Existing literature has mostly explained the occurrence of bullying victimization by individual socioemotional maladjustment. Instead, this study tested the person-group dissimilarity model (Wright et al., Journal of Personality and Social Psychology, 50: 523-536, 1986) by examining whether individuals' deviation from developmentally important (relational, socio-behavioral, and physical) descriptive classroom norms predicted victimization. Adolescents (N = 1267, k = 56 classrooms; Mage  = 13.2; 48.7% boys; 83.4% Dutch) provided self-reported and peer-nomination data throughout one school year (three timepoints). Results from group actor-partner interdependence models indicated that more person-group dissimilarity in relational characteristics (fewer friendships; incidence rate ratios [IRR]T2  = 0.28, IRRT3  = 0.16, fewer social media connections; IRRT3  = 0.13) and, particularly, lower disruptive behaviors (IRRT2  = 0.35, IRRT3  = 0.26) predicted victimization throughout the school year.

Integrating Individual Risk and Social Exposure to Violence: A Multilevel Victimization Perspective

We test two major hypotheses in this article: (a) macrolevels of school disorganization and individual levels of low self-control will be directly, and positively, linked to victimization and (bi) low self-control will have the largest impact on exposure to victimization (ETV) when it interacts with negative environments consistent with a social enhancement perspective, or (bii) low self-control will have a weaker impact on ETV when it interacts with negative environments consistent with saturation or social push models. The data for the current study were collected as part of the second International Self-Report Delinquency Study (ISRD-II). A total of 49,685 individuals from 30 countries are nested within 1,427 schools. We use multilevel generalized linear regression models with violent victimization (robbery and assault) regressed on demographic, family, school, and neighborhood variables. Multiplicative interaction terms are included in separate models to examine key moderation effects consistent with expectations drawn from the victimization literature. Analyses reveal that low self-control and perceptions of school disorganization are both associated with an increase in the odds of experiencing victimization. Interactions between low self-control and school disorganization are also found to be consistent with saturation/social push models. Our regulation approach offers a foundation for theorizing about ETV and provides a testable model for future research. However, elements of the regulation model are in need of further refinement and testing before the perspective can be moved toward a broader theory of victimization.

Physical and relational aggression as predictors of children's friendship experiences: Examining the moderating role of preference norms

Aggressive behavior is generally detrimental to children's friendships, both in terms of having friends and in terms of keeping friends. Despite this general tendency, many aggressive children have friends and some of these friendships are stable. We examined the moderating role of preference norms in the classroom and child's sex in the association between children's physical and relational aggression and their friendship experiences. A total of 1135 children (M = 10.24 years, SD = 1.01) in Grades 4 to 6 completed a peer nomination inventory in the Fall (T1) and Spring (T2) of the same school year. Norms were operationalized as the class- and sex-specific correlation between physical or relational aggression and social preference. Norms moderated associations between each form of aggression and number of friends. At T1, physical and relational aggression were concurrently associated with having more friends when norms favored this behavior and with fewer friends when norms were unfavorable. The latter effect was especially pronounced in girls. Over time, youth lost friends when norms favored physical aggression and gained friends when norms favored relational aggression. T1 friends' physical and relational aggression were strong predictors of new friends' aggressive behavior, suggesting that friends provide a type of norm more significant to new friend selection than norms of the peer group and individual aggressive behavior. Overall, our results suggest that physical and relational aggression are not necessarily detrimental to children's friendship experiences and may even be beneficial in specific social contexts.

The Quebec Newborn Twin Study at 21

This paper is a revised and updated edition of a previous description of the Quebec Newborn Twin Study (QNTS), an ongoing prospective longitudinal follow-up of a birth cohort of twins born between 1995 and 1998 in the greater Montreal area, Québec, Canada. The goal of QNTS is to document individual differences in the cognitive, behavioral, and social-emotional aspects of developmental health across childhood, their early genetic and environmental determinants, as well as their putative role in later social-emotional adjustment, school, health, and occupational outcomes. A total of 662 families of twins were initially assessed when the twins were aged 6 months. These twins and their family were then followed regularly. QNTS now has 16 waves of data collected or planned, including 5 in preschool. Over the last 24 years, a broad range of physiological, cognitive, behavioral, school, and health phenotypes were documented longitudinally through multi-informant and multimethod measurements. QNTS also entails extended and detailed multilevel assessments of proximal (e.g., parenting behaviors, peer relationships) and distal (e.g., family income) features of the child's environment. QNTS children and a subset of their parents have been genotyped, allowing for the computation of a variety of polygenic scores. This detailed longitudinal information makes QNTS uniquely suited for the study of the role of the early years and gene-environment transactions in development.

Relational victimization and elementary schoolchildren’s risk-taking behavior: Impact of the classroom norm toward risk-taking

The association between relational victimization and risk-taking development in children is understudied. Also, it is not clear how the social classroom norm may affect this link. The aim of this study was, therefore, to investigate the link between relational victimization and risk-taking behavior in elementary schoolchildren, and the potential moderating role of the classroom norm salience toward risk-taking. We expected that relationally victimized children would show an increase in risk-taking behavior in classrooms that are unfavorable toward risk-taking as a way to provoke and act against the classroom norm. However, alternatively, relationally victimized children could show an increase in risk-taking behavior in classrooms that are favorable toward risk-taking as a way to fortify the feeling of belonging to the classroom. Participants were 1,009 children (50% boys) in 69 classrooms of 13 mainstream elementary schools, followed annually across ages 7–11 (Grade 1–5). Risk-taking was assessed using the Balloon Analogue Risk Task. Relational victimization was assessed using teacher reports. The classroom norm salience toward risk-taking was based on the within-classroom correlation of risk-taking with children’s social preference score among peers. Results from multilevel modeling showed that there was no significant main effect of relational victimization on risk-taking behavior. However, the classroom norm salience toward risk-taking significantly moderated the effect of relational victimization on risk-taking. Relational victimization was related to relative increases in risk-taking when classroom norms were unfavorable toward risk-taking. In classrooms where risk-taking was favored, relational victimization was related to relative decreases in risk-taking. These findings suggest that children who are relationally victimized may engage in norm-defying behavior in their classroom. Implications for further research are discussed.

Genetic and Environmental Influences on Different Forms of Bullying Perpetration, Bullying Victimization, and Their Co-occurrence

Bullying comes in different forms, yet most previous genetically-sensitive studies have not distinguished between them. Given the serious consequences and the high prevalence of bullying, it is remarkable that the aetiology of bullying and its different forms has been under-researched. We present the first study to investigate the genetic architecture of bullying perpetration, bullying victimization, and their co-occurrence for verbal, physical and relational bullying. Primary-school teachers rated 8215 twin children on bullying perpetration and bullying victimization. For each form of bullying, we investigated, through genetic structural equation modelling, the genetic and environmental influences on being a bully, a victim or both. 34% of the children were involved as bully, victim, or both. The correlation between being a bully and being a victim varied from 0.59 (relational) to 0.85 (physical). Heritability was ~ 70% for perpetration and ~ 65% for victimization, similar in girls and boys, yet both were somewhat lower for the relational form. Shared environmental influences were modest and more pronounced among girls. The correlation between being a bully and being a victim was explained mostly by genetic factors for verbal (~ 71%) and especially physical (~ 77%) and mostly by environmental factors for relational perpetration and victimization (~ 60%). Genes play a large role in explaining which children are at high risk of being a victim, bully, or both. For victimization this suggests an evocative gene-environment correlation: some children are at risk of being exposed to bullying, partly due to genetically influenced traits. So, genetic influences make some children more vulnerable to become a bully, victim or both.

The role of norm salience in aggression socialization among friends: Distinctions between physical and relational aggression

Socialization among aggressive friends is believed to play a critical role in the development of aggressive behavior. This study examined the moderating effect of norm salience in the classroom on the association between reciprocal friends’ and children’s own physical, relational, and general aggression. A total of 713 children ( M = 10.32 years, SD = 0.99) in grades 4 to 6 completed a peer nomination inventory in the fall and spring of the same academic year. Norm salience was operationalized as the class- and sex-specific correlation between each form of aggression and social preference. Norm salience moderated relational aggression socialization among friends only for highly relationally aggressive girls. Specifically, socialization was exacerbated when norm salience was favorable and attenuated when norm salience was unfavorable, suggesting that highly relationally aggressive girls may possess skills allowing them to adapt to the social context in which they and their friends interact. In contrast, boys’ general aggression socialization was exacerbated when norm salience was neutral or unfavorable, suggesting that boys who affiliate with aggressive friends may be more susceptible to aggressive friends’ influence in general and especially in the context of potential peer rejection. No moderating effect of norm salience was found in regards to physical aggression socialization. Results suggest that interventions aimed at changing acceptability of aggression in the classroom may only be effective in specific subgroups of aggressive youth.

Age-Related Differences in the Structure of Genetic and Environmental Contributions to Types of Peer Victimization

The goal of the present investigation was to clarify and compare the structure of genetic and environmental influences on different types (e.g., physical, verbal) of peer victimization experienced by youth in pre-/early adolescence and mid-/late adolescence. Physical, verbal, social, and property-related peer victimization experiences were assessed in two twin samples (306 pairs, ages 9-14 and 294 pairs, ages 15-20). Cholesky decompositions of individual differences in victimization were conducted, and independent pathway (IP) and common pathway (CP) twin models were tested in each sample. In the younger sample, a Cholesky decomposition best described the structure of genetic and environmental contributors to peer victimization, with no evidence that common additive genetic or environmental factors influence different types of peer victimization. In the older sample, common environmental factors influenced peer victimization types via a general latent liability for peer victimization (i.e., a CP model). Whereas the pre-/early adolescent sample demonstrated no evidence of a shared genetic and environmental structure for different types of peer victimization, the mid-/late adolescent sample demonstrates the emergence of an environmentally-driven latent liability for peer victimization across peer victimization types.

The socializing effect of classroom aggression on the development of aggression and social rejection: A two-wave multilevel analysis

The current study examined the moderating effect of classroom aggression on the development of individual aggression and on the path from individual aggression to social rejection over time. The study included 1,284 elementary school children and consisted of two data waves 10months apart. At both time points, teachers assessed the children's physical and relational aggression and their social rejection status. Multi-level analyses revealed that the classroom level of relational aggression moderated the link between individual relational aggression at T1 and T2 (b=-0.18, 95% CI [-0.32, -0.05], p<.01) and the link between T1 relational aggression and T2 social rejection (b=-0.12, 95% CI [-0.23, -0.003], p<.01). Being in a classroom where relational aggression was prevalent increased relational aggression among children with a low level of relational aggression at T1. Furthermore, a high individual level of relational aggression predicted greater social rejection in classrooms with a low level of relational aggression. Children were mainly influenced by their same-gender peers. Boys as a group had a greater influence than girls on their peers of either gender in the domain of relational aggression, whereas girls as a group had a greater influence in the domain of physical aggression. The contributions of analyzing cross-level interaction to understanding the developmental patterns of aggression and social rejection in middle childhood are discussed.

School-related factors in the development of bullying perpetration and victimization: introduction to the special section

Although not limited to school contexts, bullying perpetration and victimization often emanates from social ecologies formed within the classroom. Thus, to fully illuminate risk for involvement in bullying, we must investigate contextual features of schools that heighten or minimize aggression among students and the targeting of children for peer victimization. To this end, the articles in this special section each contribute conceptually and empirically to the study of school-related factors in bullying and peer victimization. This introduction summarizes and highlights the major findings of each paper, organized around two major themes of the articles-the role of peer group ecologies and the role of the classroom teacher. We conclude our synopsis by discussing implications for intervention and the need for anti-bullying efforts that systemically address the peer group and teacher influences identified in these investigations.

The girls set the tone: gendered classroom norms and the development of aggression in adolescence

In a four-wave longitudinal study with N = 1,321 adolescents in Germany, we examined the impact of class-level normative beliefs about aggression on aggressive norms and behavior at the individual level over the course of 3 years. At each data wave, participants indicated their normative acceptance of aggressive behavior and provided self-reports of physical and relational aggression. Multilevel analyses revealed significant cross-level interactions between class-level and individual-level normative beliefs at T1 on individual differences in physical aggression at T2, and the indirect interactive effects were significant up to T4. Normative approval of aggression at the class level, especially girls' normative beliefs, defined the boundary conditions for the expression of individual differences in aggressive norms and their impact on physically and relationally aggressive behavior for both girls and boys. The findings demonstrate the moderating effect of social norms on the pathways from individual normative beliefs to aggressive behavior in adolescence.

Taking peer victimization research to the next level: complex interactions among genes, teacher attitudes/behaviors, peer ecologies, & classroom characteristics

This commentary reviews research findings of the five papers in the special entitled "School-related Factors in the Development of Bullying Perpetration and Victimization", which represent critical areas that are often overlooked in the literature. First, one paper points to the complex interaction between a genetic disposition for aggression and classroom norms toward aggression. Second, an intervention paper unpacks the underlying mechanisms of an efficacious school-wide bully prevention program by opening the "black box" and testing for mediators. Third, the remaining studies employ a wide range of rigorous designs to identify how teachers' attitudes, behaviors, and classroom practices play a critical role in the prevalence of victimization and bullying in the classroom. Further, teachers' attitudes and behaviors are shown to be predictive of youth's willingness to intervene to assist a peer who is being victimized. Results are situated in what is known about bullying prevention, and how the findings from these studies could maximize the sensitivity of future prevention efforts.