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It’s my brain’s fault! Why Teenagers Often Make Unwise Decisions

Adults exhibit a general tendency to make better decisions than adolescents, and this improvement drives an increase in specific, more sophisticated choice behaviors, according to a study published Nov. 14 in the open access journal. More biology by Vanessa Scholz and Lorenz Deserno of the University of Würzburg, Germany, and colleagues.

Learning and decision making change considerably from adolescence to adulthood. Adolescents experience developmental changes in specific choice behaviors, such as goal-directed behaviors and motivational influences on choice. They also consistently show high levels of noise in decision making, that is, choosing suboptimal options. However, it is still unknown whether these observations (the development of specific, more sophisticated choice processes and greater noise in decisions) are independent or related. It is possible that the development of specific choice processes is affected by age-dependent changes in decision noise.

To test this idea, Scholz, Deserno and their colleagues analyzed data from 93 participants between the ages of 12 and 42. Participants completed three reinforcement learning tasks: a task assessing motivational influences on choices, a learning task capturing adaptive decision making in response to environmental changes, and a task measuring goal-directed behavior.

The results revealed that noise levels were strongly correlated between reinforcement learning tasks. Crucially, noise levels mediated age-dependent increases in more sophisticated choice behaviors and improvements in performance. The findings suggest that nonspecific noise mediates the development of very specific functions or strategies.

One reason for these mediation effects could be the limited availability of cognitive resources in adolescents due to the continuous development of brain areas related to cognitive control. Having fewer cognitive resources could make adolescents more likely to rely on computationally cheaper decision strategies, making them more susceptible to emotional, motivational, and social influences.

Overall, the study provides novel insights into the computational processes underlying developmental changes in decision making. According to the authors, future work may unravel the neural basis as well as the real-life clinical and developmental relevance of decision noise for neurodevelopmental disorders.

The authors add: “Adolescents make less optimal, so-called ‘noisy’ decisions. While these noisy decisions decrease with age, this decrease is also related to the development of improved complex decision-making skills, such as planning and flexibility”.