Neural processes during adolescent risky decision making are associated with conformity to peer influence

•Adolescents’ neural responses to risky decisions may modulate their conformity to different types of peer influence.•Neural activity in the anterior cingulate cortex (ACC) predicted conformity to risky peers while driving.•Connectivity between VS and risk processing regions (including insula and ACC) predicted safer driving under risky influence. Adolescents demonstrate both heightened sensitivity to peer influence and increased risk-taking. The current study provides a novel test of how these two phenomena are related at behavioral and neural levels. Adolescent males (N = 83, 16–17 years) completed the Balloon Analogue Risk Task (BART) in an fMRI scanner. One week later, participants completed a driving task in which they drove alone and with a safety- or risk-promoting peer passenger. Results showed that neural responses during BART were associated with participants’ behavioral conformity to safe vs. risky peer influence while later driving. First, the extent that neural activation in the anterior cingulate cortex (ACC) scaled with decision stakes in BART was associated with conformity to risky peer influence. Additionally, stake-modulated functional connectivity between ventral striatum (VS) and risk processing regions (including ACC and insula) was associated with safer driving under risky peer influence (i.e. resistance to risky peer influence), suggesting that connectivity between VS and ACC as well as insula may serve a protective role under risky peer influence. Together, these results suggest that adolescents’ neural responses to risky decision making may modulate their behavioral conformity to different types of peer influence on risk taking.