Decomposing the Peer Effect on Adolescent Substance Use: Mediation, Nonlinearity, and Differential Nonlinearity*

Abstract

Although the correlation between peer delinquency and delinquency is one of the most consistently demonstrated findings in delinquency research, researchers have focused primarily on the direct, linear, and additive effects of peers in statistical models, rather than on empirically modeling mediating, nonlinear, and moderating processes that are specified by theory. To address these issues, we measure respondent delinquency and peer delinquency with illegal substance use and then decompose the effect of peer substance use on self-reported substance use. Logistic hierarchical models on a sample of adolescents from the Project on Human Development in Chicago Neighborhoods (PHDCN) indicate that the effect of peer substance use on self-reported substance use is partially mediated by perceptions of the health risks of substance use. In addition, the direct statistical effect of peers is nonlinear: On average, the peer effect decreases at higher values of peer substance use, which is consistent with a "saturation" effect. We also find that the functional form of the peer substance use/substance use relationship is dependent on the neighborhood context. In neighborhoods with more opportunities for crime, the peer effect is initially strong but decreases *

Beyond Traditional Interaction: Exploring the functional form of the exposure-offending association across online network size

“…Once this threshold is met, an increase of half a standard deviation is associated with a 5.12% decrease in personal offending, followed by a decrease of 14.15%. This finding comports with previous research based on traditional peer groups and illustrates the functional form of peer exposure is indeed nonlinear (Zimmerman & Messner, 2011;Zimmerman & Vásquez, 2011).…”

“…Using data from the Project on Human Development in Chicago Neighborhoods (PHDCN), their findings support this claim, indicating the effect of exposure to peer violence on selfreported violence becomes weaker at very high levels of exposure to peer delinquency. In a subsequent study using the same data, Zimmerman and Vásquez (2011) reported a similar nonlinear relationship between substance using peers and individual substance use. Research by Burt and Rees (2014) comports with these findings, suggesting the association between individual substance use and exposure to peer substance use was nonlinear.…”

“…Echoing a sentiment raised by Zimmerman and Vásquez (2011), peer effect research needs to transition from considering whether or not peers affect deviant and criminal behavior to identifying the conditions that influence the relationships. The current study illustrates the importance of including the size of the online network in the broader spectrum of online peer effects.…”

“…Moderate to high levels of peer behavior did not increase respondents' likelihood of engaging in these behaviors; however, those exposed to low levels of peer smoking and alcohol use were strongly influenced by their peers' behaviors. To reiterate the claims of Zimmerman and Vásquez (2011), it seems theories of peer influence must be "expanded to accommodate potential saturation effects under which the effect of deviance exposure has a maximum" (p. 1261).…”

“…Zimmerman and Messner (2011) demonstrated that exposure to pro-deviant peers influenced individual offending only to a certain point. After this saturation point was met, additional exposure to pro-deviant peers became redundant and had a diminishing effect on self-reported offending (see also Zimmerman & Vásquez, 2011). Given the mixed composition and relatively large size of online networks, it remains unclear if exposure to pro-deviant messages will achieve a saturation point after which they will have diminishing returns.…”