Do differences make the heart grow fonder? Associations between differential peer experiences on adolescent sibling...

Though it is known that different familial relationships influence one another (e.g., Yu & Gamble, 2008) the influence of outside relationships (i.e., peers) on family dynamics (i.e., sibling relationships) is less clear. Thus, the authors examined the association differential peer experiences had on the conflict frequency, conflict intensity, and relationship quality of the sibling relationship. A 1-year longitudinal design measured first-born siblings in Grades 8, 10, and 12 along with their second-born siblings. In the first year, participants were brought to the university to complete questionnaires and in the following year, siblings again participated by completing online questionnaires at home. Results partially confirmed the study hypotheses that adolescents would show greater sibling conflict and poorer relationship quality with greater peer group differences, revealing that when peer group differences between siblings were greater, the youngest siblings reported more intense sibling conflicts (pe = -.10 p < .05), the oldest siblings reported greater relationship positivity (pe = .13 p < .05), and the oldest second-borns reported greater relationship negativity (pe = -.12 p < .10). These findings underscore the importance of investigating siblings' differential experiences beyond familial influence to focus on outside sources to better understand developmental fluctuations in siblings' relationships.