SummerFest 2005 Plenary Presenter

Abstract

Longitudinal twin study of early literacy and language

This presentation describes an international, longitudinal study of young twins as they develop in literacy and language. The aim is to identify genetic and environmental sources of variation in these abilities, and in associated cognitive and behavioural processes. The twins are recruited in their final preschool year and followed for a further three years. Certain preschool abilities and insights regarded as foundational for literacy, such as phonological awareness and verbal fluency, are influenced primarily by genes, with others, such as vocabulary and syntactic processes, more affected by family environment. In school, reading ability at the word and text levels shows the effects of genes from kindergarten onwards, with little evidence of shared environment influence. Multivariate analyses reveal genetic overlap as well as degrees of genetic independence among variables, both cross-sectionally and longitudinally.

Throughout the presentation I consider layers of genetic influence, suggesting for example that the genetic effects that are detectable on vocabulary and syntax may in reality be the genetics of short-term/working memory. I also consider implications of the data for educational practice and policy.