In this study, cortical thickness (CT) and surface area (SA), estimated using magnetic resonance imaging (MRI), were investigated in 99 participants aged 8–19 years. Follow‐up MRI data were collected after on average 2.6 years for 74 individuals. The Big Five personality traits were related to longitudinal regional CT or SA development, but limited cross‐sectional relations were observed. Conscientiousness, emotional stability, and imagination were associated with more age‐expected cortical thinning over time. The results suggest that the substantial individual variability observed in personality traits may partly be explained by cortical maturation across adolescence, implying a developmental origin for personality–brain relations observed in adults.
Child Development, 2018, https://doi.org/10.1111/cdev.13016