The Development of Interpartner Aggression from Adolescence to Young Adulthood

Abstract

The overall purpose of this dissertation was to advance our knowledge of change in interpartner aggression (IPA) as adolescents become young adults. This three-study dissertation examined patterns of change and the relationship between psychological and physical forms of IPA throughout the transitional period of late adolescence to young adulthood. The data used for all three studies came from the Child Development Project (Pettit, Lansford, Malone, Dodge, & Bates, 2010) and focused on the 484 participants of that longitudinal study who provided data on their romantic relationship between the ages of 18 and 25. The first study examined multiple patterns of change in the perpetration of psychological and physical forms of IPA through latent class analysis. For both forms of aggression, a latent variable was calculated at each wave based on the occurrence versus non-occurrence of IPA behaviors in that particular year. Results indicated three trajectories of psychological and four trajectories of physical IPA. Specifically, for psychological aggression, the trajectories revealed: (a) one pattern where little or no aggression was expressed over time (Little-to-None Trajectory), (b) one pattern where participants increased in their perpetration of psychological aggression over time (Minor/Increasing Trajectory), and (c) one pattern where participants consistently expressed psychological aggression over time (Extensive Trajectory). These three patterns were also found for physical aggression along with a fourth pattern where a decrease in participants’ perpetration of physical aggression was shown (Decreasing Trajectory). Comparisons were made among the patterns by participants’ demographics and the actual aggressive behaviors more commonly expressed within each trajectory. In general, minor forms of aggression were mostly reported among trajectories for psychological and physical aggression. Participants classified in the more aggressive trajectories (Extensive, Minor/Increasing, and Decreasing Trajectories) were more likely to be females, minorities from low SES households, had less education at the age of 24, and indicated a higher length of cohabitation. Results of the first study allows for participants to be classified in their respective patterns and for pattern membership to be treated as a dependent variable. Therefore, the second study extended the findings from Study 1 by examining the following theory based variables as empirical predictors of these trajectories: (a) from social-learning/social-cognitive theory, interparental aggression, (b) from social-information processing (SIP), SIP biases, (c) from attachment theory, fearful and preoccupied attachment styles, and (d) from systems theory, discontinuity of relationship partner. Results indicated that interparental aggression predicted membership in the high stable pattern for physical aggression only. SIP biases predicted membership in the increasing and stable pattern for both psychological and physical aggression. The fearful and preoccupied attachment styles predicted membership in these same patterns for both forms of aggression, and membership in the Decreasing Trajectory for physical aggression was also predicted by the preoccupied attachment style. Lastly, discontinuity of relationship partner negatively predicted membership in the highly stable pattern for psychological aggression and in the increasing pattern for physical aggression. The third study used SEM cross-lagged analysis to examine the longitudinal relationship between psychological and physical aggression modeled as latent variables at each wave. Results indicated a stronger prediction for early reports of psychological aggression to later reports of physical aggression compared to early reports of physical aggression predicting later psychological aggression. These findings suggest that over time psychological aggression may escalate to physical aggression. Findings from these studies provide developmental implications and improve our understanding of change in IPA from adolescence to young adulthood by identifying multiple patterns of change in these behaviors throughout this transitional period, by examining how different variables representative of different theories can influence these trajectories, and by providing support for the notion that psychological aggression may be a predecessor and contributor to later physical aggression.