Social Contexts Requiring Adjudication Self- and Peer-Interest Differentially Alter Risk Preferences Across Adolescence.

Adolescence is a period of escalated rates of risk taking and a dynamic social landscape with peers taking on an important role in shaping one's decisions. Choosing to engage in risk rarely impacts only the decision maker, but also those around them. With a cohort of typically developing adolescent and young adult friend dyads (N = 128, 11-22 years), the current study investigates how peer-relevant social contexts influence risk preferences at different ages using a computational decision making task. We adapted a computational expected utility model to account for weighing the friend's outcome as part of one's utility calculation when deciding between assigning the risky option to oneself or one's friend. Compared to participants' baseline risk preferences absent of any friend involvement, we found age-related changes in risk taking when the preferred option can only be assigned to oneself or one's friend but not to both. Exploratory, data-driven analyses using behavioral measures and the computationally derived risk preference parameter revealed that overall, early adolescence is a period in which individuals assigned more weight to their friends' outcomes and were willing to forego personal benefits to a greater extent. Active observation by friends had no additional, age-dependent impact on participants' risky choices. These results indicate early adolescence to be a period of sensitivity to social contexts evoking prosocial gestures that are costly to oneself.