Peer influence plays a crucial role in the rise of health-risk behaviors during adolescence. However, there is increasing evidence that peer influence can also lead to positive psychosocial outcomes, such as prosocial behavior. The main goal of this thesis was to investigate peer influence on risk-taking and prosocial behavior in adolescence and to unravel its underlying neural processes. Findings showed that effects of peers on risk-taking behavior are dependent on the context. Adolescents take into account both social norms from peer feedback and the uncertainty associated with outcomes in risky decisions. Moreover, peers can both increase and decrease prosocial behavior in typically developing (TD) adolescents and those with autism spectrum disorders (ASD), illustrating that peer influence can also lead to more adaptive outcomes. Finally, we studied the neural processes underlying prosocial peer feedback and results indicate that prosocial peer influence is underlined by the social brain network, regions involved in thinking about the self and others. Eventually, the results of this thesis can contribute to interventions aimed at decreasing risk-taking and promoting prosocial behavior in adolescence, with possibly long lasting effects into adulthood.NWO Research Talent Grant 406-11-019 awarded to Eveline Crone & Jorien van HoornPathways through Adolescenc
