Distentangling the systems contributing to changes in learning during adolescence.

Area of Science:

• Neuroscience
• Developmental Psychology
• Cognitive Science

Background:

• Learning involves multiple neurocognitive systems, including reinforcement learning (RL) supported by dopamine and basal ganglia (BG), and working memory (WM) supported by the prefrontal cortex (PFC).
• Developmental trajectories of RL and WM systems are thought to differ, with WM/PFC developing more slowly than RL/BG.
• The combined developmental trajectories of RL and WM during adolescence are not well understood.

Purpose of the Study:

• To investigate the distinct developmental trajectories of reinforcement learning (RL) and working memory (WM) across adolescence.
• To determine how RL and WM contribute to learning performance and its changes during this developmental period.

Main Methods:

• A simple learning task assessing stimulus-action associations from feedback was administered to 187 adolescents (ages 8-17) and 53 adults (ages 25-30).
• Learning load was manipulated to test the capacity of working memory (WM).
• Computational modeling was employed to estimate individual differences in RL and WM processes.

Main Results:

• Younger children (ages 8-12) learned slower and were more sensitive to task load compared to older adolescents (ages 13-17).
• Contrary to expectations, computational modeling revealed more protracted developmental changes in RL than in WM.
• RL learning rates increased with age until 18, while WM parameters exhibited subtler, gender- and puberty-dependent changes.

Conclusions:

• Reinforcement learning (RL) systems demonstrate a more prolonged developmental course throughout adolescence than working memory (WM) systems.
• These findings challenge previous assumptions about the relative developmental timing of RL and WM.
• Understanding these distinct developmental trajectories can inform educational and intervention strategies for adolescent learning.