Modern behavior-genetic studies of twins in the United States, Australia, Scandinavia, and the United Kingdom show that genes account for most of the variance in children's reading ability by the end of the 1st year of formal reading instruction. Strong genetic influence continues across the grades, though the relevant genes vary for reading words…

Genetic and environmental relations between vocabulary and reading skills were explored longitudinally from preschool through Grades 2 and 4. At preschool there were strong shared-environment and weak genetic influences on both vocabulary and print knowledge but substantial differences in their source. Separation of etiology for vocabulary and…

The genetic factor structure of a range of learning measures was explored in twin children, recruited in preschool and followed to Grade 2 ("N"?=?2,084). Measures of orthographic learning and word reading were included in the analyses to determine how these patterned with the learning processes. An exploratory factor analysis of the…

Grade 1 literacy skills of twin children in Australia (New South Wales) and the United States (Colorado) were explored in a genetically sensitive design (N = 319 pairs). Analyses indicated strong genetic influence on word and nonword identification, reading comprehension, and spelling. Rapid naming showed more modest, though reliable, genetic…

Reports on a study of Grade 5 children who had been trained in phoneme identity six years earlier. Results reveal that these children were superior to untrained controls on irregular word reading and on a composite list of nonwords, regular words, and irregular words. Preschool instruction in phonemic structure had modest but detectable effects on…

Examines the word-reading strategies of a sample of second- and third-grade students in normal classrooms, focusing on the students' relative reliance on decoding versus sight-word associations. Suggests that lack of efficient decoding skills will begin to take a toll on reading comprehension by grade 3. (SR)