Behavioral pathways from sibling relationships in adolescence to romantic partnerships in adulthood.

Sibling relationships in adolescence provide rich and relevant socializing opportunities for developing early adult romantic relationships, but much less is known regarding the effect of siblings on future romantic partnerships. Using a prospective, longitudinal design, we investigated the association between observed positive behaviors (warmth, support, positive communication), sibling pairs during adolescence (7th, 8th, 9th, and 10th grades), and the same observed behaviors between adult romantic partners nearly two decades later (M age = 31 years old). In structural equation models (SEMs), we tested four dyadic pathways of interest: (1) individual behavioral continuity; (2) evocative partner effects; (3) sibling modeling; and (4) sibling-to-partner matching. In multiple group analyses, we also investigated gendered socialization effects for different sibling dyads (i.e., brother-brother; sister-sister; and mixed-sex sibling pairs). Results showed strong continuity from adolescent behavior toward their sibling to the same behavior toward their romantic partner in early adulthood, but there was no evidence for sibling modeling effects nor for sibling matching. We also found significant differences between sister-sister sibling dyads compared to brother-brother and mixed-sex sibling dyads for the evocative pathway. Findings highlight the "long view" of positive adolescent behavior in sibling relationships for shaping future romantic partnerships in adulthood.