title: Dramatic increase in heritability of cognitive development from early to middle childhood: an 8-year longitudinal study of 8,700 pairs of twins.
abstract: The generalist genes hypothesis implies that general cognitive ability (g) is an essential target for understanding how genetic polymorphisms influence the development of the human brain. Using 8,791 twin pairs from the Twins Early Development Study, we examine genetic stability and change in the etiology of g assessed by diverse measures during the critical transition from early to middle childhood. The heritability of a latent g factor in early childhood is 23%, whereas shared environment accounts for 74% of the variance. In contrast, in middle childhood, heritability of a latent g factor is 62%, and shared environment accounts for 33%. Despite increasing importance of genetic influences and declining influence of shared environment, similar genetic and shared environmental factors affect g from early to middle childhood, as indicated by a cross-age genetic correlation of .57 and a shared environmental correlation of .65. These findings set constraints on how genetic and environmental variation affects the developing brain.
authors.affiliation: Social, Genetic and Developmental Psychiatry Centre, Institute of Psychiatry, King's College London, De Crespigny Park, London SE5 8AF, United Kingdom. oliver.davis@iop.kcl.ac.uk
authors.forename: Oliver S P
authors.initials: OS
authors.lastname: Davis
authors.forename: Claire M A
authors.initials: CM
authors.lastname: Haworth
authors.forename: Robert
authors.initials: R
authors.lastname: Plomin
mesh_terms: D000367:Age Factors; D002648:Child; D002657:Child Development; D002675:Child, Preschool; D003071:Cognition; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D025341:Principal Component Analysis; D012931:Social Environment; D013647:Task Performance and Analysis; D014427:Twins / Q000235:genetics*; D006113:United Kingdom; D014705:Verbal Behavior