A stochastic actor-based model was used to investigate the origins of sex segregation by examining how similarity in sex and time spent in gender-typed activities affected affiliation network selection and how peers influenced children’s (N = 292; M age = 4.3 years) activity involvement. Gender had powerful effects on interactions through direct and indirect pathways. Children selected playmates of the same-sex and with similar levels of gender-typed activities. Selection based on gender-typed activities partially mediated selection based on sex. Children influenced one another’s engagement in gender-typed activities. When mechanisms producing sex segregation were compared, the largest contributor was selection based on sex; less was due to activity-based selection and peer influence. Implications for sex segregation and gender development are discussed.

Ethnic-racial identity formation represents a key developmental task that is especially salient during adolescence and has been associated with many indices of positive adjustment. The Identity Project intervention, which targeted ethnic-racial identity exploration and resolution, was designed based on the theory that program-induced changes in ethnic-racial identity would lead to better psychosocial adjustment (e.g., global identity cohesion, self-esteem, mental health, academic achievement). Adolescents (N =215; Mage =15.02, SD =.68; 50% female) participated in a small-scale randomized control trial with an attention control group. A cascading mediation model was tested using pre-test and three follow-up assessments (12, 18, and 67 weeks after baseline). The program led to increases in exploration, subsequent increases in resolution and, in turn, higher global identity cohesion, higher self-esteem, lower depressive symptoms, and better grades. Results support the notion that increasing adolescents' ethnic-racial identity can promote positive psychosocial functioning among youth.

Much research has explored the role of social networks in promoting health through the provision of social support. However, little work has examined how social networks themselves may be structured by health. This article investigates the link between individuals' health and the characteristics of their social network positions. We first develop theoretical predictions for how health may influence the structure of adolescent networks. We then test these predictions using longitudinal analysis of the National Longitudinal Study of Adolescent Health (Add Health). We find important relationships between the health status of adolescents and the characteristics of the social network positions within which they are embedded. Overall we find that adolescents in poor health form smaller local networks and occupy less central global positions than their healthy peers. These results also have implications for social network research, expanding the scope of factors responsible for the network positions individuals occupy.

The peer context features prominently in theory, and increasingly in empirical research, about ethnic-racial identity (ERI) development, but no studies have assessed peer influence on ERI using methods designed to properly assess peer influence. We examined peer influence on ERI centrality, private, and public regard using longitudinal social network analysis. Data were drawn from two sites: a predominantly Latina/o Southwestern (SW) school (N = 1034; Mage = 12.10) and a diverse Midwestern (MW) school (N = 513; Mage = 11.99). Findings showed that peers influenced each other's public regard over time at both sites. However, peer influence on centrality was evident in the SW site, whereas peer influence on private regard was evident in the MW site. Importantly, peer influence was evident after controlling for selection effects. Our integration of developmental, contextual, and social network perspectives offers a fruitful approach to explicate how ERI content may shift in early adolescence as a function of peer influence.

Conventional wisdom holds that friends protect against depression through the social support they provide; however, depression likely has a role in structuring friendship networks. In particular, we investigate friend selection mechanisms responsible for similarity in depression among friends (i.e., homophily). Preference is one explanation, yet several correlates of depression make homophilous selection among depressed individuals unlikely. We propose two alternative mechanisms-avoidance and withdrawal-that can produce depression homophily in the absence of preference. These alternative mechanisms create homophily indirectly by limiting friendship partners available to depressed individuals. We test the preference, avoidance, and withdrawal mechanisms using data from the National Longitudinal Study of Adolescent Health and a dynamic network model. Results provide support for the withdrawal mechanism. These findings help explain how depression affects friend selection and have broader implications for understanding selection mechanisms responsible for network patterns such as homophily.