When we looked at how age interacted with heritability values in the pediatric sample, we found that the pattern depended on the region of the cortex. Regions such as the primary motor and sensory cortices that were not highly heritable in adults were significantly heritable in younger children but became progressively less so with time. Conversely, areas that were strongly heritable in adults were less so earlier in development. Instead, heritability in these regions gradually increased over childhood and adolescence. In the oldest ages heritability in the frontal and temporal regions was of comparable magnitude to that reported in the adult study, suggesting that the lower heritability seen when the sample was taken as a whole may have related to the lower average age of the sample (Figure 4).
