Charting the cognitive development of children using adult 'polygenic g scores'.

The most highly predictive polygenic scores in the behavioural sciences are for cognitive traits, especially general cognitive ability (g) and educational achievement. We combined polygenic scores derived from genome-wide association studies of adult g and educational attainment, conditioned on their prediction of adult g, to create adult 'polygenic g scores' which we used to chart the course of cognitive development of 10,000 white British children from infancy through early adulthood. We integrated cross-sectional regression, latent growth curve, and cross-time common factor analysis to systematically characterise cognitive development. Polygenic g score showed minimal prediction in infancy, modest prediction in childhood, and substantial prediction by early adulthood, accounting for 12% of the variance. Higher polygenic g scores were associated with faster cognitive growth in latent growth models. Prediction was strongest for a cross-time common cognitive factor (15%), reflecting substantial stable genetic influences across development. We also examined the polygenic g score's prediction of educational achievement, behaviour problems, and anthropometric outcomes and found similar developmental increases in prediction for educational achievement. Together, our findings demonstrated that adult polygenic g scores can be a useful tool for charting the development of cognitive traits.