Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Human Development and Family Studies

Committee Chair(s)

Shawn Whiteman


Shawn Whiteman


Diana Meter


Travis Dorsch


Families are a critical part of an individual's development, yet sibling influences on development are rarely studied. Siblings often share the same genetics and live in the same environment, yet many remark that they are nothing like their brothers or sisters. One proposed reason for these differences is sibling differentiation, a process by which individuals become different from their sibling in order to reduce conflict and rivalry as well as increase intimacy in the sibling relationship. To date, this process has been studied from the perspective of the younger sibling; the current study focused on older siblings. Using longitudinal data from 682 families, I first investigated predictors of older siblings’ engagement in differentiation and found that unlike previous studies which showed differentiation was most likely to occur between siblings of the same gender who were close in age, older siblings’ reports of differentiation was not predicted by these structural factors. Instead, older siblings’ differentiation was predicted by their proclivity for social comparison, parental favoritism, and younger siblings’ reports of differentiation. Secondly, I investigated whether differentiation improves sibling relationships over time. In contrast to theoretical predictions, but consistent with recent empirical work, I found that differentiation was not correlated with improved sibling relationships; instead, differentiation was associated with increased conflict and decreased intimacy two years later.