Aims: Adolescence is a critical period characterized by increased sensation-seeking, risk-taking, and sensitivity to rewards, alongside neural and behavioral changes. Research suggests that alterations in functional connectivity within and between cortical and subcortical areas optimize interregional communication, impacting reward processing and decision-making. Hormonal changes, notably gonadal hormones, significantly influence adolescent behavior and brain development. This study aims to elucidate adolescent behavior through a reward learning paradigm while investigating underlying neuronal and hormonal developmental changes.Methods: Employing a probabilistic reward-learning task and fMRI resting-state imaging, we examined 32 adolescents (aged 13-17 years) and 26 adults (aged 30-40 years), evaluating behavior, hormonal levels, and functional connectivity. Utilizing a hierarchical Bayesian framework, we simultaneously modeled reinforcement learning (behavior) and functional connectivity in the reward circuit (neural data), efficiently estimating subject-specific behavioral parameters and exploring their relationships with functional brain connectivity. Finally, we compared the hierarchical model with a win-stay lose-switch model.Results: Adolescents exhibited higher learning rates (α) and inverse temperatures (β) compared to adults. Analysis revealed the anterior cingulate cortex (ACC) as a pivotal region, in connection with learning rate. Hormonal levels did not significantly impact the relationship between behavioral parameters and connectivity.Conclusion: This study provides foundational insights into the complex interplay among reward processing, brain connectivity, and developmental changes during adolescence. Adolescents demonstrated distinct decision-making mechanisms characterized by lower integration of feedback and decreased exploratory behavior compared to adults. The ACC emerged as a critical region encoding decision-making costs, highlighting differences in decision-making processes between adolescents and adults.