Forms and Functions of Aggression 1 RUNNING HEAD: FORMS AND FUNCTIONS OF AGGRESSION Profiles of the Forms and Functions of Self-Reported Aggression in Three Adolescent Samples

In the current study, we addressed several issues related to the forms (physical and relational) and functions (reactive and proactive) of aggression in community (n = 307), voluntary residential (n = 1,917) and involuntarily detained (n = 659) adolescents (ages 11 to 19 years). Across samples, boys self-reported more physical aggression and girls reported more relational aggression, with the exception of higher levels of both forms of aggression in detained girls. Further, few boys showed high rates of relational aggression without also showing high rates of physical aggression. In contrast, it was not uncommon for girls to show high rates of relational aggression alone and these girls tended to also have high levels of problem behavior (e.g., delinquency) and mental health problems (e.g., emotional dysregulation, callousunemotional traits). Finally, for physical aggression in both boys and girls, and for relational aggression in girls, there was a clear pattern of aggressive behavior that emerged from cluster analyses across samples. Two aggression clusters emerged with one group showing moderately high reactive aggression and a second group showing both high reactive and high proactive aggression (combined group). On measures of severity (e.g., self-reported delinquency and arrests) and etiologically important variables (e.g., emotional regulation and callous-unemotional traits), the reactive aggression group was more severe than a non-aggressive cluster but less severe than the combined aggressive cluster. Forms and Functions of Aggression 3 Profiles of the Forms and Functions of Self-Reported Aggression in Three Adolescent Samples The research of Nicki R. Crick has been instrumental in advancing our understanding of aggressive behavior. In particular, Crick’s work has been critical for defining the various ways that aggression can be expressed in children and adolescents, especially in terms of its forms and functions. While physical aggression has long been a construct of interest in the social sciences because, by definition, it leads to physical harm to its victims (Berkowitz, 1993), Crick’s work was influential in drawing attention to another form aggression in which the victim’s relationships are harmed (Crick, Ostrov, & Kawabata, 2007). Relational aggression consists of behaviors such as gossiping about others, excluding children from a peer group, spreading rumors, or telling others not to be friends with a child (Björkqvist, Lagerspetz, & Kaukiainen, 1992; Crick & Grotpeter, 1995; Lagerspetz, Björkqvist, & Peltonen, 1988). This form of aggression is associated with a host of social and psychological problems in both the victims and perpetrators of the aggressive behavior (see Marsee & Frick, 2010, for a review). Crick’s work has also been instrumental in elucidating the different functions served by aggressive behavior, whether physical or relational (Crick & Dodge, 1996; Mathieson & Crick, 2010; Ostrov & Crick, 2007). Specifically, reactive aggression occurs as an angry response to real or perceived provocation or threat, whereas proactive aggression is typically unprovoked and is often used for instrumental gain or dominance over others (Dodge, 1991; Dodge & Coie, 1987). Broadening and refining definitions of aggressive behavior to consider these different forms and functions has had important implications for understanding gender differences in the way aggression may be expressed (Cullerton-Sen et al., 2008) and in understanding the different causal processes that underlie aggression (Dodge & Pettit, 2003; Marsee & Frick, 2010). Forms and Functions of Aggression 4 However, there are a number of issues arising from this research that could use clarification. These issues are relevant for advancing Crick’s seminal work on the causes of aggression and for the development of effective treatments to reduce aggressive behavior in children and adolescents (Leff & Crick, 2010). In this paper, we attempt to address several of these important outstanding issues. The first issue is clarifying the association between gender and the different forms of aggression. The construct of relational aggression was developed to tap methods of harming others that may be preferred by girls. This preference may be due to cultural prohibitions over the expression of physical aggression in girls as well as the greater importance of relationships to girls, which may result in attempts to harm relationships being more hurtful to them (Crick, 1996; Crick & Grotpeter, 1995; Galen & Underwood, 1997). In a comprehensive meta-analytic review of 148 studies, Card, Stucky, Sawalani, and Little (2008) reported that the association between gender and physical aggression (r = .29) was positive and significant (with boys showing more physical aggression), whereas the association between gender and relational aggression was significantly different from zero, but too small to be considered meaningful (r = .03). These findings suggest that the male predominance in aggression is largely confined to physical aggression. However, these findings do not support the contention that girls show more relational aggression than boys but instead, suggest that boys and girls show equivalent levels of this form of aggression. Card et al. (2008) considered whether the method of assessing physical aggression influenced associations with gender, with parent-reports and self-reports yielding the smallest associations (r = .15 and .21, respectively), and peer reports yielding the largest (r = .37). For relational aggression, parent and teacher reports resulted in effects of girls showing more Forms and Functions of Aggression 5 relational aggression than boys (r = -.08 and -.07 for parent and teacher report, respectively), whereas boys self-reported slightly more relational aggression (r = .03); however, all of these effects were small in magnitude. There are two possible influences on the relationship between gender and the forms aggression that were not considered in the meta-analysis. One is whether the measures of physical and relational aggression were equivalent in their coverage of relevant aggressive behaviors. For example, items related to relational aggression may be worded to detect less severe and more normative types of harmful behavior than items assessing physical aggression, and such differences in severity could influence the associations with gender. A second possible influence is the type of sample studied, such that it is not clear whether gender differences in type of aggression are similar across samples that may differ on their base rate of aggression. Thus, in the current study, we examined gender differences in the forms of aggression using a self-report measure designed to have similar items (similar in number, rating format, and severity) assessing physical aggression and relational aggression. Further, we examined possible gender differences in three samples of adolescents in various settings (i.e., community, residential treatment, detained) to examine the robustness of associations with gender across types of samples using the same measure. Another consideration in exploring gender differences in the forms of aggression is whether the forms differ in their incremental utility in predicting problematic outcomes in boys and girls. Specifically, boys and girls may not differ in their level of relational aggression, but this type of aggression may predict problems in adjustment for girls more than for boys, even when controlling for level of physical aggression. In support of this possibility, several studies have found that relational aggression predicts social-psychological maladjustment above and beyond overt aggression more consistently for girls than for boys (Crick, 1996; Crick & Forms and Functions of Aggression 6 Grotpeter, 1995; Cullerton-Sen et al., 2008; Marsee & Frick, 2007; Prinstein, Boergers, & Vernberg, 2001). A related question is whether there are children who show high rates of relational but not physical aggression who also show problems in adjustment that may warrant intervention. This question is critical for determining whether relational aggression should be considered in criteria for mental health conditions because it would indicate that criteria focused only on physical aggression may miss impaired children in need of treatment (Frick & Nigg, 2012). Further, it is essential to investigate whether these profiles of aggression differ by gender, such that boys may exhibit both physical and relational aggression when aggressive, whereas girls may be more likely to show only relational aggression. Addressing this question requires a person-centered approach to data analyses that has not been commonly used in past work. In one notable exception, Crapanzano, Frick, and Terranova (2010) used cluster analyses to study the patterns of aggressive behavior displayed in a sample of middle school students and found a cluster of girls who were high on relational aggression but who showed normative levels of physical aggression. These relationally aggressive girls also showed problems in adjustment, such as higher rates of anger, impulsivity, and bullying compared to girls with normative levels of aggression. Unfortunately, this study did not report whether there was a group of purely relationally aggressive boys who also showed problems in adjustment. Thus, in the current study we examined profiles of physical and relational aggression (i.e., forms of aggression) across three adolescent samples to determine whether purely relationally aggressive groups of both boys and girls emerged and, if so, whether they showed problems in adjustment. The final issue investigated in the present study was whether profiles of reactive and proactive aggression (i.e., the functions of aggression) varied across the different study samples. Forms and Functions of Aggression 7 Reactive and proactive aggression have emerged as separate dimensions in factor analyses (Little, Jones, Henrich, & Hawley, 2003; Poulin & Boivin, 2000) and research has documented differences in their emotional and cognitive correlates. Specifically, reactive aggression has been linked to low frustration tolerance, poorly regulated emotional responses to provocation, impulsivity, and a tendency to misinterpret ambiguous behaviors as hostile provocation (Atkins, Osborne, Bennett, Hess, & Halperin, 2001; Muñoz, Frick, Kimonis, & Aucoin, 2008; Phillips & Lochman, 2003). In contrast, proactive aggression has been associated with the tendency to view aggression as an effective means to reach goals (i.e., positive outcome expectancies), reduced emotional responsiveness to negative emotional stimuli, and a callous-unemotional interpersonal style (i.e., lacking guilt and empathy; a callous manipulation of others) (Crick & Dodge, 1996; Frick, Cornell, Barry, Bodin, & Dane, 2003; Hubbard et al., 2002). Although the vast majority of these studies of the different functions of aggression have focused on physical aggression, there is evidence that relational aggression can also be divided into both reactive and proactive types (Little et al., 2003; Marsee et al., 2011) and that these two types of relational aggression show different associations with several theoretically important variables (Marsee & Frick, 2007; Marsee et al., 2011; Mathieson & Crick, 2010). For example, Marsee and Frick (2007) reported that reactive relational aggression was uniquely associated with poorly regulated emotion and anger to perceived provocation, whereas proactive relational aggression was uniquely associated with callous-unemotional (CU) traits and positive outcome expectations for aggression in a detained sample of girls. Thus, causal theories of aggression must consider these different functions of aggression in order to fully explain the construct. Causal theories must also account for the high correlation between the two types of aggression, which ranges from .40 to .90 across samples of youth with the typical estimate being Forms and Functions of Aggression 8 about .70 (Little et al., 2003; Poulin & Boivin, 2000). Further, research has consistently shown an asymmetry in the overlap between the two types of aggression. Specifically, there appears to be a significant number of children who only show reactive aggression, whereas most children who show high levels of proactive aggression also show high rates of reactive aggression (Brown, Atkins, Osborne, & Milnamow, 1996; Dodge & Coie, 1987; Frick et al., 2003; Muñoz et al., 2008; Pitts, 1997). The high correlation between the two types of aggression and the fact that the combined aggressive group is typically more aggressive overall has led some researchers to question whether the two functions of aggression reflect different patterns of behavior with unique causal factors (Bushman & Anderson, 2001; Walters, 2005). That is, an alternative way of interpreting these findings is that proactive aggression is simply a marker of a more severe pattern of aggression, and not a different type of aggression. Thus, in the current study, we test whether distinct profiles of reactive and proactive behavior emerge across samples, across gender, and across the different forms of aggression when using the same measure. Further, we test whether the profiles differ on severity (e.g., the combined proactive and reactive groups showing more problems in adjustment) and/or on types of risk factors (e.g., the pure reactive group showing more problems in emotional regulation and the combined group showing more CU traits). To summarize, in the current study we address three important issues for understanding the forms and functions of aggression across three different samples that likely vary in their base rate of aggression. First, we address the question of whether gender differences in physical and relational aggression are consistent across these different types of samples when using the same measure of aggression designed to have similar items assessing the different forms of aggression. Second, we address the question of whether a purely relationally aggressive group (i.e., low on Forms and Functions of Aggression 9 physical aggression) of both boys and girls emerges across samples and whether this group shows signs of psychosocial impairment. Third, we address the question of whether profiles of aggressive behaviors differing in their function that have been found in past studies (e.g., a group moderately high on reactive aggression only, a group high on both reactive and proactive aggression) can be consistently replicated across the different samples using the same measure of aggression. Further, we test differences across groups on important variables to determine whether adolescents with distinct profiles of aggressive behavior differ on severity of impairment and/or type of risk factors relevant to causal theory. Method (Sample 1Community)