Susceptibility to Peer Influence, Social Exclusion, and Adolescent Risky Decisions

Understanding the mechanisms of poor decision making and risk behavior in adolescence is an important goal. Two important features of adolescence relevant to these concerns are the saliency of social acceptance and increased frequency of making decisions in the company of peers. The current study examines individual differences in susceptibility to peer influence and the effect of positive and negative social contexts on adolescent decision making. Fifty-five adolescents (11.2-17.6 years of age) completed measures of social susceptibility and risk behavior and subsequently underwent functional magnetic resonance imaging while completing a simulated driving game in three conditions: alone, while being watched by peers, and after an event of social exclusion. Individual differences in susceptibility to peers predicted a decrease in adaptive decision making following exclusion by peers. Adolescents with greater self-reported engagement in substance use, risky sexual behavior, and aggressive behavior performed worse on the game following social exclusion. Neuroimaging results showed relatively greater activation in the striatum during risky decisions (Go through a yellow light) in the peer condition compared to the social exclusion condition. Whole-brain and region of interest analyses revealed a significant decrease in striatal activity during Go decisions following social exclusion. Adolescents who were more susceptible to peer influence and engaged in more risk behavior evidenced the greatest decreases in striatal activity after social exclusion. Results suggest that susceptibility to peer influence interacts with the experience of social exclusion to produce maladaptive decision making in adolescents. More broadly, the results demonstrate that individual differences and social contexts are both important factors affecting adolescent decisions and that changes in momentary levels of social acceptance can influence the quality of adolescent decisions in social situations. These findings suggest that the explanatory power of existing models of adolescent decision making could be extended by exploring individual differences in decision making within and across social contexts, including peer influence and social exclusion, to provide a more comprehensive account of which adolescents are prone to making poor decisions and when