Austerberry, C., Fearon, P., Ronald, A., Leve, L. D., Ganiban, J. M., Natsuaki, M. N., Shaw, D. S., Neiderhiser, J. M., & Reiss, D. (2022). Early manifestations of intellectual ability: Evidence that genetic effects on later achievement are mediated through verbal ability in early childhood. Child Development, 93:e188–e206.

Intellectual ability is highly heritable and robustly predicts lifelong health and adjustment outcomes but the earliest manifestations of this asset are unknown. This study examined whether early executive function (EF) or verbal ability mediate genetic influences on subsequent intellectual ability in a sample of 561 adoptees (57% male), their birth and adoptive parents (70% and 92% Caucasian, 13% and 4% African American, 7% and 2% Latinx, respectively). Genetic influences on children’s achievement at age 7 years were almost entirely mediated by verbal ability at 4.5 years (β = .22, 95% CI [0.08, 0.35], p = .002) and not via EF, indicating that verbal ability is an early manifestation of genetic propensity for achievement and represents a key target for intervention.