Sibling aggression is one of the most frequently occurring forms of aggression within the family and has been associated with socioemotional problems. Guided by the cultural context perspective and family systems theory, a conceptual model depicting the direct and indirect effects of cultural orientation values, traditional gender role attitudes, parental differential treatment, and parent-child conflict on sibling aggression and psychosocial functioning (i.e., psychological distress and interpersonal difficulties) was developed. It was hypothesized that perceptions of cultural values and gender role attitudes endorsed by primary caregivers would be associated with family dynamics factors (i.e., parental differential treatment and parent-child conflict) that contributed to sibling aggression and resulting impaired psychosocial functioning. A total of 272 participants completed the online questionnaire that measured the variables of interest. Structural equation modeling (SEM) methods were used to analyze the data. Findings of the final models lent clear support to the indirect effects of cultural values and gender role attitudes on sibling aggression and resulting psychosocial functioning through differential treatment and parent-child conflict although the results also yielded some unexpected nuances regarding the indirect effect paths. Specifically, lower levels of independent cultural values contributed to greater levels of sibling aggression and impaired psychosocial functioning through more differential treatment and parent-child conflict, while higher levels of traditional gender role attitudes contributed to the outcome variables only through differential treatment. Findings are discussed from the cultural context and family systems framework. Limitations, future directions, and clinical implications are also discussed.

Three empirical studies comprising this dissertation were carried out to provide a more comprehensive understanding of concurrent measures of both predictors and outcomes of young adolescents' sibling interactions. The participants included older siblings (M age = 14.3), younger siblings (M age = 11.6), and their mothers from approximately 450 families who completed web-based surveys.Study one examined correlates of overt and relational aggression between young adolescent siblings. Family environment emerged as an important factor in explaining internalizing problems as well as overt/relational aggression for both younger and older siblings. Findings also provided partial support for the positive linkages between young adolescents' aggression and their own and siblings' internalizing problems above and beyond family and maternal variables. The main purpose of the study two was to investigate self-criticism as a potential mediating factor in the link between mother-child relationships and aggression or perceptions of social competence. Maternal self-criticism strongly corresponded to the quality of relationships with children, and an intergenerational similarity of self-criticism, particularly for older children, was found. Mother-child relationships and adolescent self-criticism were significantly related to aggression and perceptions of social competence. In addition, the link between mother-child relationships and aggression or social competence is mediated, in part, by self-criticism in adolescents. Using social control theory and attachment theory as guides, study three examined how qualities of young adolescents' social relationships (i.e., mother, sibling, and friend), and dynamic interactions among characteristics of those relationships, are associated with school involvement and delinquency. Results were largely consistent with tenets of social control theory and attachment theory. Young adolescents' social relationships were associated with their adjustment in ways that are protective or beneficial. Furthermore, these social affordances worked additively and in compensatory ways to promote positive adjustment. Positive relationship qualities tended to amplify other relational influences promoting successful development, and these findings were invariant across gender.While optimal mother-child relationships are central in nurturing the child's capacity to develop warm and harmonious sibling relationships in both a direct and an indirect manner, there is a considerable contribution of siblings to adjustment and socialization above and beyond the effects of mother-child relationships.

Past research has investigated parameters of time-out such as duration, mostly with individuals with developmental disabilities. Existing research and popular parenting sources do not coincide in terms of the suggested duration of time-out. The current study sought to find the shortest effective duration(s) of time-out necessary to reduce sibling aggression in eight typically developing girls ages 3-7. The intervention took place in participants’ homes using a minute-by-minute incremental increase and reversal design. All participants reached a minimum reduction in sibling aggression of 60% after experiencing a 1-min time-out. The majority (75%) of participants also demonstrated clear reversals of behavior when returned to the baseline condition. The current findings suggest that a 1-min time-out may be sufficient for children as old as 7— contrary to the common 1-min per year of age rule. Limitations include the presence of a graduate assistant during sibling play and some loss of experimental control in the natural setting. Future research should seek to replicate the current methodology with the same population and populations of different ages and developmental levels.

This study aims to explore the perspective of school counsellors on sibling violence, focusing on their understanding of the phenomenon through their professional experiences and their perceptions of their own abilities in addressing it. The study was conducted through a qualitative approach, where six school counsellors working with teenagers aged thirteen years and up were interviewed using a semi-structured interview method. The findings of this study suggest that school counsellors play an important role in identifying, responding, and promoting change in cases of sibling violence within the school system. Furthermore, their observations indicate that the family environment can be significant to the occurrence of sibling violence through the normalisation and perpetuation of the violence, be it directly or through a general culture of violence in the family. Additionally, the occurrence of sibling violence has also been observed to have some potential consequences for persons experiencing it, such as anxiety, low self-esteem, and mistrust of others.