title: Genetic effects on children's conversational language use.
abstract: OBJECTIVE
  The present study examined the extent of genetic and environmental influences on individual differences in children's conversational language use.
  
  
  METHODS
  Behavioral genetic analyses focused on conversational measures and 2 standardized tests from 380 twins (M = 7.13 years) during the 2nd year of the Western Reserve Reading Project (S. A. Petrill, K. Deater-Deckard, L. A. Thompson, L. S. DeThorne, & C. Schatschneider, 2006) Multivariate analyses using latent factors were conducted to examine the extent of genetic overlap and specificity between conversational and formalized language.
  
  
  RESULTS
  Multivariate analyses revealed a heritability of .70 for the conversational language factor and .45 for the formal language factor, with a significant genetic correlation of .37 between the two factors. Specific genetic effects were also significant for the conversational factor.
  
  
  CONCLUSIONS
  The current study indicated that over half of the variance in children's conversational language skills can be accounted for by genetic effects with no evidence of significant shared environmental influence. This finding casts an alternative lens on past studies that have attributed differences in children's spontaneous language use to differences in environmental language exposure. In addition, multivariate results generally support the context-dependent construction of language knowledge, as suggested by the theory of activity and situated cognition (J. S. Brown, A. Collins, & P. Duguid, 1989; T. A. Ukrainetz, 1998), but also indicate some degree of overlap between language use in conversational and formalized assessment contexts.
authors: University of Illinois at Urbana-Champaign, 901 South Sixth Street, Champaign, IL 61820, USA. lauras@uiuc.edu
authors: Laura S
authors: LS
authors: DeThorne
authors: Stephen A
authors: SA
authors: Petrill
authors: Sara A
authors: SA
authors: Hart
authors: Ron W
authors: RW
authors: Channell
authors: Rebecca J
authors: RJ
authors: Campbell
authors: Kirby
authors: K
authors: Deater-Deckard
authors: Lee Anne
authors: LA
authors: Thompson
authors: David J
authors: DJ
authors: Vandenbergh
mesh_terms: D002648:Child; D002657:Child Development; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007804:Language Development; D007807:Language Tests; D008297:Male; D008957:Models, Genetic; D015999:Multivariate Analysis; D012931:Social Environment; D014429:Twins, Dizygotic; D014430:Twins, Monozygotic; D014825:Vocabulary