The results of this longitudinal study also indicate significant age-related changes in DD, suggesting a decrease in the propensity for impulsive choice during early adolescence. This finding is consistent with the notion that adolescence is a period of significant changes in cognitive and emotional systems and their underlying neural substrates (Ernst and Mueller 2008). Despite the relatively narrow age range in the present study, the findings suggest a significant trend towards the increasing role of the “reflective” system and decreasing role of the “impulsive” system as adolescents grow older (Bickel et al. 2007).
