posted on 2022-02-23, 05:15authored byNicole Harlaar, Laura Segebart DeThorne, Jamie Mahurin-Smith, Mariana Aparicio Betancourt, Stephen A. Petrill
Purpose: We evaluated genetic and environmental
contributions to individual differences in language skills
during early adolescence, measured by both language
sampling and standardized tests, and examined the extent
to which these genetic and environmental effects are stable
Method: We used structural equation modeling on latent
factors to estimate additive genetic, shared environmental,
and nonshared environmental effects on variance in
standardized language skills (i.e., Formal Language) and
productive language-sample measures (i.e., Productive
Language) in a sample of 527 twins across 3 time points
(mean ages 10–12 years).
Results: Individual differences in the Formal Language
factor were influenced primarily by genetic factors at
each age, whereas individual differences in the Productive
Language factor were primarily due to nonshared
environmental influences. For the Formal Language factor,
the stability of genetic effects was high across all 3 time
points. For the Productive Language factor, nonshared
environmental effects showed low but statistically significant
stability across adjacent time points.
Conclusions: The etiology of language outcomes may differ
substantially depending on assessment context. In addition, the
potential mechanisms for nonshared environmental influences
on language development warrant further investigation.
This project was supported by National Institute of Child Health and Human Development Grants HD38075, HD46167, and HD050307 (awarded to Stephen Petrill).