标题：The Interplay of Friendship Networks and Social Networking Sites: Longitudinal Analysis of Selection and Influence Effects on Adolescent Smoking and Alcohol Use
摘要：Objectives. We examined the coevolution of adolescent friendships and peer influences with respect to their risk behaviors and social networking site use. Methods. Investigators of the Social Network Study collected longitudinal data during fall 2010 and spring 2011 from 10th-grade students in 5 Southern California high schools (n = 1434). We used meta-analyses of stochastic actor-based models to estimate changes in friendship ties and risk behaviors and the effects of Facebook and MySpace use. Results. Significant shifts in adolescent smoking and drinking occurred despite little change in overall prevalence rates. Students with higher levels of alcohol use were more likely to send and receive friendship nominations and become friends with other drinkers. They were also more likely to increase alcohol use if their friends drank more. Adolescents selected friends with similar Facebook and MySpace use habits. Exposure to friends’ risky online pictures increased smoking behaviors but had no significant effects on alcohol use. Conclusions. Our findings support a greater focus on friendship selection mechanisms in school-based alcohol use interventions. Social media platforms may help identify at-risk adolescent groups and foster positive norms about risk behaviors. It is well established that adolescents’ risk behaviors, such as smoking and alcohol use, are associated with their friends’ behaviors. 1–6 Friendships have also been shown to be the most salient relationship through which these behavioral influences are transmitted, especially during adolescence, 7 because of an increase in shared activities 8 and opportunities for socialization. 9 Furthermore, the desire for peer affirmation, social status, and group membership 10,11 make adolescents particularly susceptible to normative influences. 12,13 These influence processes play a significant role in the adoption of risk behaviors such as cigarette smoking and substance use.
