Genetic effects on children's conversational language use.
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.
DeThorne
Laura S
LS
University of Illinois at Urbana-Champaign, 901 South Sixth Street, Champaign, IL 61820, USA. lauras@uiuc.edu
Petrill
Stephen A
SA
Hart
Sara A
SA
Channell
Ron W
RW
Campbell
Rebecca J
RJ
Deater-Deckard
Kirby
K
Thompson
Lee Anne
LA
Vandenbergh
David J
DJ
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