This study used a short-term longitudinal design with theoretically derived preregistered hypotheses and analyses to examine the role of temperament in the development of forms (i.e., physical and relational) and functions (i.e., proactive and reactive) of aggressive behavior in early childhood (N = 300, M age = 44.70 months, SD = 4.38, 44% girls). Temperament was measured via behavioral reports of emotional dysregulation, fearlessness/daring, and rule internalization/empathy and, in a subsample that completed a physiological assessment, via skin conductance and respiratory sinus arrhythmia. Emotion dysregulation generally served as a risk factor for all subtypes of aggression, with evidence of stronger associations with reactive as compared to proactive functions of relational aggression for girls. Daring predicted increases in physical aggression, especially among boys, and rule internalization predicted decreases in relational aggression, especially among girls. Rule internalization mediated longitudinal associations between daring and proactive relational aggression for girls. Some evidence also emerged supporting associations between adaptive functioning (i.e., high empathy, high respiratory sinus arrhythmia) and proactive functions of aggression. Findings highlight distinct temperamental risk factors for physical versus relational aggression and provide partial support for gender-linked theories of the development of aggression.

This study tested the independent effects and interactions of sympathetic nervous system reactivity and hostile attribution biases (HAB) in predicting change in pure and co-occurring relational bullying and victimization experiences over one year. Co-occurring and pure relational bullying and victimization experiences were measured using a dimensional bifactor model, aiming to address methodological limitations of categorical approaches, using data from 300 preschoolers (Mage = 44.70 months, SD = 4.38). Factor scores were then saved and used in nested path analyses with a subset of participants (n = 81) to test main study hypotheses regarding effects of HAB and skin conductance level reactivity (SCL-R). Bifactor models provided good fit to the data at two independent time points. HAB and SCL-R interacted to predict increases in co-occurring relational bullying/victimization with evidence for over- and underarousal pathways.

The current study examined a bifactor model of affective dimensions of withdrawal. Specifically, a model which specified a general factor of anxious-avoidant withdrawal (i.e., withdrawal with negative affect), a specific factor of unsociability (i.e., withdrawal without negative affect), and a specific factor of negative affect without withdrawal was specified in the primary sample (n = 238, 56.3% boys, M age = 44.92 months, SD = 5.32 months) and a validation sample (n = 332, 52.6% boys, M age = 47.11 months, SD = 7.32 months). The model provided a good fit to the data in both samples. In the primary sample, longitudinal relations between the bifactor model and peer victimization were examined across three time points (Time 1 in the spring, Time 2 in the fall, and Time 3 in the spring). Results showed that negative affect without withdrawal was concurrently associated with higher levels of relational and physical victimization at T1, unsociability predicted reductions in relational victimization from T1 to T2 as children entered a new classroom, and anxious-avoidant withdrawal predicted reductions in relational and physical victimization from T2 to T3 as children acclimated to the new classroom. Developmental considerations and clinical implications are discussed.

A short-term longitudinal study during early childhood (N = 301; 155 girls; M = 44.76 months old, SD = 8.20) investigated the prospective associations between peer victimization and aggression subtypes. Specifically, observations of relational and physical victimization as well as teacher reports of the forms (i.e., relational and physical) and functions (i.e., proactive and reactive) of aggression were collected at two time points during an academic year. Within- and between-group gender differences were examined as part of the preliminary analyses. In order to address key study questions, both directions of effect between peer victimization and aggression subtypes were examined. We found that teacher-reported proactive relational aggression predicted decreases in observed relational victimization over time, whereas reactive relational aggression predicted increases in observed relational victimization over time. Ways in which these and other findings extend the literature are discussed.

A secondary analysis of the National Institute of Child Health and Human Development Study of Early Child Care and Youth Development was conducted to test the mechanisms by which relational aggression in third grade was associated both directly and indirectly with relational victimization in sixth grade. A large sample (N = 1,035; 522 girls; M = 8.3 years old; SD = 0.23) and multiple informants (teacher, child, and parent report) and methods were used to test several theoretically driven hypotheses. Our path analysis model suggested evidence for both direct and indirect pathways consistent with the sequential social process model of peer harassment. Relational aggression was significantly associated with future relational victimization even after controlling for physical aggression and gender. Loneliness mediated the direct association between relational aggression and peer victimization. A second model testing the reverse direction of effect revealed that relational victimization in third grade predicted relational aggression in sixth grade and was associated with loneliness and depressive symptoms in fifth grade, but there was no evidence for any of the indirect pathways.

Trajectories of relational aggression were examined in a large, diverse sample of fourth-grade students. Hierarchical linear modeling was used to examine relational aggression over 1 calendar year. The results indicated that relational aggression increased in a linear fashion for girls over the course of the study. In addition, increases in friend intimate exchange were associated with time-dependent increases in relational aggression among girls only. Relational aggression and internalizing “tracked” together across the course of the study. Overall, the findings suggest relational aggression becomes increasingly common among elementary school girls, and girls' close, dyadic relationships may fuel relationally aggressive behavior in some contexts. Finally, the results indicate that relational aggression trajectories are dynamically associated with maladjustment.This study was funded by grants from NIMH (MH63684) and NSF (BCS-0126521) to N. C. Crick. Preparation of this manuscript was supported by a NIMH Traineeship (MH-15755) to D. Murray-Close and J. M. Ostrov. Portions of this manuscript were presented at the 2004 Biennial Meeting of The Society for Research on Adolescence, Baltimore, MD. We thank Kathleen E. Woods for her assistance and comments on an earlier draft, Dr. Jeff Long for his statistical consultation and assistance with this study, and Peter Ralston and the entire School Buddies Project team for assistance with the collection of this data. Finally, we thank the principals, teachers, parents, and children for their participation.