Micaela E. Christopher|Jacqueline Hulslander|Brian Byrne|Stefan Samuelsson|Janice M. Keenan|Bruce F. Pennington|John C. DeFries|Sally J. Wadsworth|Erik G. Willcutt|Richard K. Olson
The genetic and environmental etiologies of individual differences in early reading growth in Australia, the United States, and Scandinavia
University of Colorado Boulder|University of Colorado Boulder|University of New England|Linköping University|Linköping University|University of Denver|University of Denver|University of Colorado Boulder|University of Colorado Boulder|University of Colorado Boulder|University of Colorado Boulder|Linköping University
first crosscountry twin study individual differences reading growth postkindergarten postsecond grade analyzed data 487 twin pairs united states 267 twin pairs australia 280 twin pairs scandinavia data two reading measures fit biometric latent growth models individual differences reading measures postkindergarten united states australia due primarily genetic influences genetic shared environmental influences scandinavia contrast individual differences growth generally large genetic influences countries results suggest genetic influences largely responsible individual differences early reading development addition timing start formal literacy instruction may affect etiology individual differences early reading development limited influence etiology individual differences growth