To Örebro University

Objective: This study examined developmental trends of peer selection and socialization related to friends' alcohol use in early-, middle-, and late-adolescent peer networks, with the primary goal of identifying when these mechanisms emerge, when these mechanisms exert their strongest effects, and when (or if) they decrease in importance. Gender and reciprocity are also tested as moderators of selection and socialization.

Method: Cross-sequential study (three age cohorts assessed at three annual measurements) of 950 youth (53% male) initially attending classrooms in Grade 4 (n = 314; M = 10.1 years), Grade 7 (n = 335; M = 13.1 years), and Grade 10 (n = 301; M = 16.2 years).

Results: Similarity between friends' drinking behaviors emerged in Grade 6, peaked in Grade 8, and decreased throughout late adolescence. Adolescents in all three age groups selected peers with similar drinking behaviors, with effects being more robust for early-adolescent males and for late-adolescent females. Peers' alcohol use emerged as a significant predictor of middle-adolescent alcohol use and remained a significant predictor of individual drinking behaviors throughout late adolescence. Socialization did not differ as a function of gender or reciprocity.

Conclusions: Alcohol-related peer selection was relatively more important than socialization in early-adolescent friendship networks; both mechanisms contributed to explaining similarity between the drinking behaviors of friends in middle and late adolescence. Effects of peer socialization emerged in middle adolescence and remained throughout late adolescence. (J Stud. Alcohol Drugs, 73, 89-98, 2012)