Adolescence is associated with elevated risk-taking behaviour, which has been linked to immature reward processing in subcortical brain regions, particularly the ventral striatum. Although reward prediction error signalling and adolescent risk-taking have been examined separately, relatively few studies have directly integrated developmental differences in ventral striatal RPE signals with behavioural risk-taking outcomes. The present study examines the extent to which age-related differences in ventral striatal reward prediction error signals explain elevated risk-taking behaviour in adolescents compared to adults. A literature review was combined with a partial analysis of published summary statistics from Vaidya et al. (2013), comparing fMRI responses to monetary rewards across 18 adolescents and 18 young adults. Demographic analysis of Smith et al. (2024) dataset was conducted to contextualise lifespan coverage across 114 participants aged 21-80. Adolescents showed attenuated ventral striatal sensitivity to reward magnitude differences relative to adults, reflected in a significant reward magnitude by age group interaction in right VS: F(2, 68) = 4.27, p = 0.02. Adults demonstrated contextual recalibration of VS reward signals depending on relative reward value, a pattern absent in adolescents. Lower VS differentiation was independently associated with higher impulsivity scores across both groups, and adolescents scored significantly higher on impulsivity than adults. These findings partially support the dual-systems model, suggesting adolescent risk-taking reflects an immature RPE signalling system characterised by reduced magnitude sensitivity and context-insensitive reward encoding. Causal inference is limited by the cross-sectional design and single primary source, and future longitudinal research with larger and more diverse samples is needed.
Haris Younis (Sun,) studied this question.