Why teenagers often make less than optimal decisions

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

Learning and decision-making change considerably from adolescence into adulthood. Adolescents undergo developmental changes in specific choice behaviors, such as goal-directed behaviors and motivational influences over choice. They also consistently show high levels of decision noise, i.e., choosing suboptimal options.

However, it remains unknown whether these observations—the development of specific and more sophisticated choice processes and higher decision noise—are independent or related. It is possible that the development of specific choice processes might be impacted by age-dependent changes in decision noise.

To test this idea, Scholz, Deserno, and colleagues analyzed data from 93 participants between 12 and 42 years of age. The participants completed three reinforcement learning tasks: a task assessing motivational influences over 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 across reinforcement learning tasks. Critically, noise levels mediated age-dependent increases in more sophisticated choice behaviors and performance gains. The findings suggest that unspecific noise mediates the development of highly specific functions or strategies.

One reason for these mediation effects could be a limited availability of cognitive resources in adolescents due to the ongoing development of brain areas related to cognitive control. Having fewer cognitive resources might make adolescents more prone to rely on computationally cheaper decision strategies, rendering 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 developmental and clinical real-life relevance of decision noise for neurodevelopmental disorders.

The authors add, “Teenagers make less optimal, so-called ‘noisy’ decisions. While these noisy decisions decrease when growing older, this decrease is also linked to the development of improved complex decision-making skills, such as planning and flexibility.”