title: The structure of language abilities at 4 years: a twin study.
abstract: Normal language development was studied in 310 pairs of 4-year-old twins born in the United Kingdom in 1994. Twins were assessed individually in their homes on a diverse battery of language and nonverbal measures. Rotated factor analyses indicated the presence of a general Language factor (L) as well as a general Nonverbal (NV) factor. Moderate genetic influence was found for both L and NV abilities. Bivariate genetic analysis estimated a genetic correlation of .63 between L and NV abilities, implying that over half of the genetic influence on L overlaps with genetic influence on NV. These results suggest that at age 4, genetic influences on individual differences in language overlap substantially with genetic influences on individual differences in other cognitive abilities, although perhaps less so than later in development.
authors.affiliation: Social, Genetic, and Developmental Psychiatry Research Center, Institute of Psychiatry, London, England. e.colledge@iop.kcl.ac.uk
authors.forename: Essi
authors.initials: E
authors.lastname: Colledge
authors.forename: Dorothy V M
authors.initials: DV
authors.lastname: Bishop
authors.forename: Gesina
authors.initials: G
authors.lastname: Koeppen-Schomerus
authors.forename: Thomas S
authors.initials: TS
authors.lastname: Price
authors.forename: Francesca G E
authors.initials: FG
authors.lastname: Happé
authors.forename: Thalia C
authors.initials: TC
authors.lastname: Eley
authors.forename: Philip S
authors.initials: PS
authors.lastname: Dale
authors.forename: Robert
authors.initials: R
authors.lastname: Plomin
mesh_terms: D002663:Child Language; D002675:Child, Preschool; D004777:Environment; D005163:Factor Analysis, Statistical; D005260:Female; D006801:Humans; D007206:Individuality; D007804:Language Development; D007807:Language Tests / Q000706:statistics & numerical data; D008297:Male; D015999:Multivariate Analysis; D009633:Nonverbal Communication / Q000502:physiology; D010641:Phenotype; D012737:Sex Factors; D011795:Surveys and Questionnaires; D014427:Twins / Q000235:genetics / Q000523:psychology*; D006113:United Kingdom