Stephen A. Petrill|Sara A. Hart|Nicole Harlaar|Jessica Logan|Laura M. Justice|Christopher Schatschneider|Lee A. Thompson|Laura S. DeThorne|Kirby Deater?Deckard|Laurie E. Cutting
Genetic and environmental influences on the growth of early reading skills
The Ohio State University|The Ohio State University|The Ohio State University|The Ohio State University|The Ohio State University|Florida State University|Case Western Reserve University|University of Illinois System|Virginia Tech|Vanderbilt University
background studies suggested genetic environmental influences overall level early reading whereas larger reading literature shown environmental influences rate growth early reading skills study first examine genetic environmental influences initial level performance rate subsequent growth early reading methods participants drawn western reserve reading project study 314 twin pairs based ohio twins assessed via three annual home visits early elementary school assessments included word identification letter identification pseudoword decoding expressive vocabulary phoneme awareness rapid naming measures analyzed using latent growth curve modeling results heritability initial performance latent intercept ranged h 2 38 word identification h 2 72 rapid naming shared environment ranged c 2 11 rapid naming c 2 62 word identification heritability rate subsequent growth latent slope statistically significant rapid naming h 2 58 phoneme awareness h 2 20 shared environment accounted nearly 100 variance rate growth word identification letter identification pseudoword decoding statistically significant large phoneme awareness c 2 80 genetic variance rapid naming phoneme awareness latent slopes overlapped entirely genetic variance intercepts contrast onethird twothirds shared environmental variance slope independent shared environmental variance intercept conclusions genetic influences related primarily already present initial level performance contrast shared environmental influences affecting rate growth predicted independent initial levels performance results suggested growth early reading skills amenable family school environmental influences reading skills develop