Peer presence increases adolescent risk-taking by enhancing activity in the brain's reward circuitry. Using fMRI, the study found that adolescents showed greater activation in reward-related brain regions, such as the ventral striatum and orbitofrontal cortex, when observed by peers. This increased activation predicted subsequent risk-taking behavior. In contrast, adults showed less activation in these regions, and cognitive control areas were less engaged in adolescents than in adults. The presence of peers heightened sensitivity to the potential reward value of risky decisions, contributing to increased risk-taking in adolescents. The study suggests that the maturational imbalance between the incentive processing system and the cognitive control system underlies this increased risk-taking behavior in adolescents when peers are present. The findings highlight the role of social context in adolescent decision-making and provide insights into the neurobiological mechanisms underlying peer influence on risk-taking behavior.Peer presence increases adolescent risk-taking by enhancing activity in the brain's reward circuitry. Using fMRI, the study found that adolescents showed greater activation in reward-related brain regions, such as the ventral striatum and orbitofrontal cortex, when observed by peers. This increased activation predicted subsequent risk-taking behavior. In contrast, adults showed less activation in these regions, and cognitive control areas were less engaged in adolescents than in adults. The presence of peers heightened sensitivity to the potential reward value of risky decisions, contributing to increased risk-taking in adolescents. The study suggests that the maturational imbalance between the incentive processing system and the cognitive control system underlies this increased risk-taking behavior in adolescents when peers are present. The findings highlight the role of social context in adolescent decision-making and provide insights into the neurobiological mechanisms underlying peer influence on risk-taking behavior.