Abstract
Adolescent success providing satisfying support in response to a close friend's call in a caregiving task was examined as a potentially fundamental developmental competence likely to predict future social functioning, adult caregiving security, and physical health. Adolescents (86 males, 98 females; 58% White, 29% African American, 8% mixed race/ethnicity, 5% other) were followed from ages 13 to 33 (1998-2021) using multiple methods and reporters. Early caregiving success was found to predict greater self- and partner-reported caregiving security, lower negativity in adult relationships, and higher adult vagal tone. Results are interpreted as advancing our understanding beyond simply recognizing that adolescent friendships have long-term import, to now identifying specific capacities within friendships that are linked to longer-term outcomes.