Stefan Samuelsson|Richard K. Olson|Sally J. Wadsworth|Robin P. Corley|John C. DeFries|Erik G. Willcutt|Jacqueline Hulslander|Brian Byrne
Genetic and environmental influences on prereading skills and early reading and spelling development in the United States, Australia, and Scandinavia
Linköping University|University of Colorado Denver|University of Colorado Denver|University of Colorado Denver|University of Colorado Denver|University of Colorado Denver|University of Colorado Denver|University of New England
genetic environmental influences prereading skills preschool early reading spelling development end kindergarten compared among samples identical fraternal twins us colorado australia scandinavia mean comparisons revealed significantly lower preschool print knowledge scandinavia consistent relatively lower amount shared book reading letterbased activities parents lack emphasis print knowledge scandinavian preschools patterns correlations preschool environment measures prereading skills within samples remarkably similar patterns genetic shared environment nonshared environment estimates samples genetic influence substantial shared environment influence relatively weak phonological awareness rapid naming verbal memory genetic influence weak shared environment influence relatively strong vocabulary print knowledge contrast reading spelling assessed end kindergarten australian us samples preliminary evidence country differences magnitude genetic environmental influences argue apparently higher genetic lower shared environment influence australian sample related greater emphasis formal reading instruction resulting advanced reading spelling skills end kindergarten thus greater opportunity observe genetic influences response systematic reading instruction among australian twins