Citation
Dayley, Jenna C. (2022). SIBLINGS INFLUENCE ON YOUNG ADULTS’ DEVELOPMENT: A THREE-STUDY DISSERTATION.Abstract
The nature and correlates of sibling relationships and sibling influence processes have been examined during childhood and adolescence; however, they have been understudied in early adulthood. Across three studies, this dissertation addressed this gap by examining the implications of sibling modeling and differentiation processes during young adulthood across multiple domains of young adult development. Using data from 2,145 unique sibling pairs from the National Study of Adolescent to Adult Health (Add Health), Study 1 examined whether young adult siblings bidirectionally (i.e., older-to-younger sibling as well as younger-to-older sibling) influenced eachother in terms of binge drinking, marijuana use, risky sexual behaviors, civic engagement, and volunteering behaviors. Additionally, this study examined the degree to which sibling closeness exacerbated similarities between siblings. Study 2 investigated the developmental implications of sibling differentiation in young adulthood utilizing data from 1,750 young adults participating in the Sibling Influence on Becoming Adults Study (SIBS). Specifically, across three waves of data, I examined whether sibling differentiation indirectly predicted young adults’ well-being by improving
sibling relational harmony (i.e., increasing sibling intimacy and decreasing sibling conflict). Finally, using data from young adult sibling dyads from Penn State Family Relationships Project, Study 3 explored whether domain specific sibling modeling and sibling differentiation uniquely shaped sibling similarities/differences in terms of academic achievement, work prestige, and romantic love. Study 1 found evidence of bidirectional sibling influence in several domains (but not all); however, these findings were not moderated by sibling closeness. In Study 2, sibling differentiation predicted less harmonious sibling relationships, which in turn, were related to poorer well-being. Finally, Study 3 found evidence for bidirectional sibling influence in terms of romantic love, but not educational or work attainment.
Overall, findings suggest that in domains where development continues into young adulthood, older and younger siblings may shape each other’s behaviors and attitudes. Although the salience of modeling and differentiation processes may diminish in young adulthood, it is possible that other sibling relational qualities play a more important role in sibling similarities/differences, given the significant changes to the sibling relationship during this period. As such, future research should continue
to examine the implications of sibling relationships during young adulthood, paying particular attention to sibling relational qualities like contact, disclosure, and support