Social influences on decision-making are particularly pronounced during adolescence and have both protective and detrimental effects. To evaluate how responsiveness to social signals may be linked to substance use in adolescents, we used functional neuroimaging and a gambling task in which adolescents who have and have not used substances (substance-exposed and substance-naïve, respectively) made choices alone and after observing peers’ decisions. Using quantitative model-based analyses, we identify behavioral and neural evidence that observing others’ safe choices increases the subjective value and selection of safe options for substance-naïve relative to substance-exposed adolescents. Moreover, the effects of observing others’ risky choices do not vary by substance exposure. These results provide neurobehavioral evidence for a role of positive peers (here, those who make safer choices) in guiding adolescent real-world risky decision-making.

社会对决策的影响在青春期尤其明显，既有保护作用，也有有害作用。为了评估青少年对社交信号的反应如何与物质使用相关，我们使用了功能性神经影像学和一项赌博任务，其中使用过和未使用过物质（分别是接触过物质和未接触过物质）的青少年单独和事后做出选择观察同伴的决定。使用基于定量模型的分析，我们确定了行为和神经证据，表明观察他人的安全选择相对于接触物质的青少年而言，增加了未接触过物质的青少年的主观价值和安全选择的选择。此外，观察他人冒险选择的影响并不因物质暴露而变化。这些结果为积极的同龄人（在这里是那些做出更安全选择的人）在指导青少年现实世界的风险决策中的作用提供了神经行为证据。