This article reports a longitudinal study of the social interaction pa
tterns of college students and adults. Adults (N = 113) from 26 to 31
years old who had participated in similar studies in college kept deta
iled records of social activity for 2 weeks. Three hypotheses were sup
ported. First, from college to adulthood, opposite-sex socializing gre
w, whereas same-sex, mixed-sex, and group interactions decreased. Seco
nd, intimacy increased in adulthood, whereas satisfaction did not. Con
trary to theories that focus on the formation of primary intimate rela
tionships in early adulthood, intimacy increased in all interaction ca
tegories. Sex differences in the development of intimacy were also not
ed. Third, correlations revealed marked consistency over time in sever
al variables. Implications of these findings for social development du
ring early adulthood were examined.