Genetic and environmental mediation of the prediction from preschool language and nonverbal ability to 7-year reading


Address for correspondence: M. E. Hayiou-Thomas, Department of Psychology, University of York, York YO10 5DD, UK. E-mail:


We use a genetically sensitive design to examine the relationship between language and nonverbal ability at 4½ and reading skills at 7 years of age in a sample of more than 1,000 children participating in the Twins Early Development Study. We find that nonphonological as well as phonological measures of early language make significant contributions towards the prediction of reading at 7, and that nonverbal ability at 4½ is an equally strong predictor. With respect to aetiology, we find substantial genetic contributions towards the relationship between early language skills and reading at 7, as well as a trend towards shared environmental influences. The genetic continuity is not specific to the verbal domain, however, as we also find a substantial genetic relationship between nonverbal ability at 4½ and reading at 7.