Limited evidence supports the external validity of the distinction between developmental phonological and surface dyslexia. We previously identified children ages 8 to 13 meeting criteria for these subtypes (Peterson, Pennington, & Olson, 2013) and now report on their reading and related skills approximately 5 years later. Longitudinal…

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…

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…

Does the choice of test for assessing reading comprehension influence the outcome of genetic analyses? A twin design compared two types of reading comprehension tests classified as primarily associated with word decoding (RC-D) or listening comprehension (RC-LC). For both types of tests, the overall genetic influence is high and nearly identical.…

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…

Twin children from Australia, Scandinavia, and the United States were assessed for inattention, hyperactivity-impulsivity, and reading across the first 3 school years. Univariate behavior-genetic analyses indicated substantial heritability for all three variables in all years. Longitudinal analyses showed one genetic source operating across the…

Individual differences in word recognition, spelling, and reading comprehension for 324 children at a mean age of 16 were predicted from their reading-related skills (phoneme awareness, phonological decoding, rapid naming, and IQ) at a mean age of 10 years, after controlling the predictors for the autoregressive effects of the correlated reading…

Spelling errors in the Wide Range Achievement Test were analyzed for 77 pairs of children, each of which included one older child with spelling disability (SD) and one spelling-level-matched younger child with normal spelling ability from the Colorado Learning Disabilities Research Center database. Spelling error analysis consisted of a percent…

Comprehension tests are often used interchangeably, suggesting an implicit assumption that they are all measuring the same thing. We examine the validity of this assumption by comparing some of the most popular reading comprehension measures used in research and clinical practice in the United States: the Gray Oral Reading Test (GORT), the two…

We conducted behavior?genetic analyses of kindergarten reading, spelling, phonological awareness, rapid naming, and spoken sentence processing in 172 pairs of monozygotic and 153 pairs of same-sex dizygotic twin kindergarten children sampled in the United States and Australia. We also modeled progress from preschool to kindergarten in…

Environment and Genes are often found in the titles of my articles, but this is the first and most likely the last of my titles to include SSSR. This article is based on my presidential address at the 10th annual meeting of the Society for the Scientific Study of Reading (SSSR) in Boulder, Colorado (2003), so I begin with some reflection on the…

Investigates whether two different versions of the serial rapid automatized naming (RAN) task, using similar alphanumeric stimuli, would differentially predict performance on word level reading skills. Indicates that the RAN-Alternative measure explained significantly more unique variance in word recognition and orthographic-processing skills than…

Reports results from one- and two-year follow-up tests for children with reading problems who had previously received 25 hours of training in one of two computer-based remediation programs. Finds children initially trained in phonological skills made greater gains in phonological awareness, phonological decoding, and untimed word recognition at…