Aggression is inherently social. Evolutionary theories, for instance, suggest that the peer group within which an aggressor is embedded is of central importance to the use of aggression. However, there is disagreement in the field with regard to understanding precisely how aggression and peer relationships should relate. As such, in a series of three empirical studies, my dissertation takes a relational approach and addresses some of the inconsistencies present in the extant literature. In Study 1, I examined how qualities of youth's close friendships contributed to the use of aggression, both concurrently and over time. I found that youth with large friendship networks were more aggressive, whereas those with highly interconnected friendship network decreased in aggression over time. Using a dyadic mediation model, the second study considered the precursors to aggressors' friendships with peers. Specifically, I explored aggressive youth's interactions with unfamiliar peers and assessed how the interactions that unfold affected the quality of the relationship. I found that dyads who were highly discrepant in their tendencies toward aggression failed to collaborate well with one another, and this led to less positive perceptions of one another. Whereas the first two studies concerned aggressors' relationships with their friends (Study 1) and acquaintances (Study 2), Study 3 focused on a different type of relationship – the relationship between an aggressor and his or her victim(s). In the third study, I explored how power dynamics operate within an aggressor-victim dyad and assessed whether differences in the balance of power between the aggressor and victim affected the strength of their relationship. I found that more aggressor-victim dyads were characterized by a relative balance than imbalance in power, and that power balanced dyads had stronger and more sustained aggressor-victim relationships. By taking a relational approach to the study of aggression, this dissertation has advanced extant work in the field. That is, these findings move away from the simplification and aggregation of relational constructs (e.g., relationships, friendships), and instead consider the nuances of specific types of relationships or interactions with specific peers, allowing for a better understanding of the relational nature of aggression.

The majority of early education programs today use a mix of child-centered and direct instruction approaches. Existing research comparing educational approaches is limited in the degree to which it can inform practice in mixed-method classrooms (i.e., classrooms using both child-centered and direct instruction approaches). The current dissertation extended previous research examining child-centered and direct instruction approaches to early education in two studies. The first study explored how free play and guided play differ from one another. The second study examined how time spent in free play, guided play, and direct instruction in the fall related to children's school readiness in the spring. Both studies were conducted using mixed-method Head Start classrooms. Participants were preschool children (Study 1 n = 284, Study 2 n = 283; M age = 52 months, 48% girls, 70% Mexican or Mexican-American) from lower socioeconomic status families. Observational data were utilized to assess children's time spent in free play and guided play and experiences with activities and peers in each context. Children's academic, affective, and social readiness were assessed through child interviews and teacher reports. The results provided little evidence to support the hypotheses or the popularly held belief that guided play is the most beneficial context for learning and development in early education programs. Findings were discussed in terms of the strengths and limitations of the studies and directions for future research. Importantly, recommendations for policy and practice were provided.

Although aggression is sometimes thought to be maladaptive, evolutionary theories of resource control and dominance posit that aggression may be used to gain and maintain high social prominence within the peer group. The success of using aggression to increase social prominence may depend on the form of aggression used (relational versus physical), the gender of the aggressor, and the prominence of the victim. Thus, the current study examined the associations between aggression and victimization and social prominence. In addition, the current study extended previous research by examining multiple forms of aggression and victimization and conceptualizing and measuring social prominence using social network analysis. Participants were 339 6th grade students from ethnically diverse backgrounds (50.4% girls). Participants completed a peer nomination measure assessing relational and physical aggression and victimization. They also nominated friends within their grade, which were used to calculate three indices of social prominence, using social network analysis. As expected, results indicated that relational aggression was associated with higher social prominence, particularly for girls, whereas physical aggression was less robustly associated with social prominence. Results for victimization were less clear, but suggested that, for girls, those at mid-levels of social prominence were most highly victimized. For boys, results indicated that those both high and low in prominence were most highly relationally victimized, and those at mid-levels of prominence were most highly physically victimized. These findings help inform intervention work focused on decreasing overall levels of aggressive behavior.

In response to the recent publication and media coverage of several books that support educating boys and girls separately, more public schools in the United States are beginning to offer same-sex schooling options. Indeed, students may be more comfortable interacting solely with same-sex peers, as boys and girls often have difficulty in their interactions with each other; however, given that boys and girls often interact beyond the classroom, researchers must discover why boys and girls suffer difficult other-sex interactions and determine what can be done to improve them. We present two studies aimed at examining such processes. Both studies were conducted from a dynamical systems perspective that highlights the role of variability in dyadic social interactions to capture temporal changes in interpersonal coordination. The first focused on the utility of applying dynamics to the study of same- and mixed-sex interactions and examined the relation of the quality of those interactions to participants' perceptions of their interaction partners. The second study was an extension of the first, examining how dynamical dyadic coordination affected students' self-perceived abilities and beliefs in science, with the intention of examining social predictors of girls' and women's under-representation in science, technology, engineering, and mathematics.

The current study was a benefit cost analysis that examined mental and behavioral health and prescription drug service use data of 347 participants (212 youth and 135 caregivers) from a bereavement intervention, the Family Bereavement Program (FBP).The preliminary goals of the current study were to compare the FBP intervention and the Literature Control (LC) groups at the six year follow-up on: (a) number of participants using mental/behavioral health services and prescription drugs, (b) the frequency of use of mental/behavioral health services and prescription drugs, and (c) the costs of mental/behavioral health services and prescription drugs. The final, and primary goal, was to (d) calculate the benefits of the FBP by analyzing the monetary difference between the LC and FBP groups in terms of cost of services used and then by applying those benefits to the cost of the intervention. Data representing participating youths' and caregivers' mental health service use and prescription drug use at the sixth year post-intervention were collected, as were the costs of those services. Results indicated that fewer FBP participants used services and prescription drugs than the Literature Control (LC) participants, but FBP participants, particularly the youth, used some low intensity services more frequently whereas the LC youth used more intensive and costly services more frequently. Consequently, service costs were greater for participants in the LC group than for participants in the FBP group. The benefit cost ratio revealed that the FBP, as delivered, saved society between $.15 and $.27 in mental and behavioral health costs for every dollar spent on the intervention. Implications of these findings and directions for future research are discussed.

In preschool, learning often occurs within the context of children’s play activities with various toys and materials. Although much theoretical speculation has occurred, relatively little empirical research has examined how preschoolers’ play activities foster children’s learning and academic skill development. The current study extended previous research on dimensions of adolescent activity involvement to young children in preschool by assessing dimensions of activity involvement across and within curriculum-based and gender-based activity domains. In a longitudinal design, I explored the relation between these dimensions of activity involvement in the fall semester of children’s preschool year and children’s academic outcomes at the end of their preschool year. Participants included preschool children (n = 279; M age = 52 months, 47% girls, 70% Mexican or Mexican-American) from lower socioeconomic status families. Children’s activity involvement was observed, and academic abilities were assessed through child interviews and teacher reports. The results provided little evidence to support the hypotheses that children’s dimensions of activity involvement in the fall semester of their preschool year contributed to their academic abilities in literacy and mathematics at the end of their preschool year. Findings were discussed in terms of the strengths and limitations of the present study. Potentially important steps remain for research on the relation between preschool activity involvement and academic abilities.