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Pennington, Bruce F.; McGrath, Lauren M.; Rosenberg, Jenni; Barnard, Holly; Smith, Shelley D.; Willcutt, Erik G.; Friend, Angela; DeFries, John C.; Olson, Richard K. – Developmental Psychology, 2009
This article examines Gene x Environment (G x E) interactions in two comorbid developmental disorders--reading disability (RD) and attention-deficit/hyperactivity disorder (ADHD)--as a window on broader issues on G x E interactions in developmental psychology. The authors first briefly review types of G x E interactions, methods for detecting…
Descriptors: Reading Difficulties, Attention Deficit Hyperactivity Disorder, Interaction, Developmental Psychology
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Davis, Chayna J.; Knopik, Valerie S.; Olson, Richard K.; Wadsworth, Sally J.; DeFries, John C. – Annals of Dyslexia, 2001
A study assessed genetic and environmental etiologies of reading, rapid naming (RN), and their covariation using data from 587 twin pairs (ages 7-20) in which one student had reading difficulties and from 360 control pairs. Correlation between reading and RN performances for subjects was significantly higher than that of controls. (Contains…
Descriptors: Biological Influences, Elementary Secondary Education, Environmental Influences, Etiology
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Castles, Anne; Datta, Helen; Gayan, Javier; Olson, Richard K. – Journal of Experimental Child Psychology, 1999
Examined heritability of reading deficits in dyslexic subtypes. Found reading deficits were heritable in developmental phonological and surface dyslexics, with greater genetic contribution in the former. Findings suggest a partial independence in the development of cognitive processes involved in reading, and affirm accounts of surface dyslexia…
Descriptors: Adolescents, Biological Influences, Children, Cognitive Development
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Wadsworth, Sally J.; Olson, Richard K.; Pennington, Bruce F.; DeFries, John C. – Journal of Learning Disabilities, 2000
Composite reading performance data from 223 pairs of identical twins and 169 same-gender fraternal twins in which at least one member was classified with reading disability were subjected to multiple regression analysis. Results indicated that the genetic etiology of reading disability differs as a linear function of IQ. (Contains extensive…
Descriptors: Biological Influences, Children, Disability Identification, Environmental Influences
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Byrne, Brian; Delaland, Cara; Fielding-Barnsley, Ruth; Quain, Peter; Samuelsson, Stefan; Hoien, Torleiv; Corley, Robin; DeFries, John C.; Wadsworth, Sally; Willcutt, Erik; Olson, Richard K. – Annals of Dyslexia, 2002
Preliminary results from data on 146 Australian, 284 American, and 70 Norwegian preschool twins indicate reliable genetic influences on phonological awareness and memory and learning. Vocabulary, grammar, and morphology showed significant shared environment and negligible genetic effects. A print knowledge composite showed genetic and shared…
Descriptors: Beginning Reading, Biological Influences, Cognitive Processes, Dyslexia