Extensive evidence and theory suggest that the development of motor skills during infancy and early childhood initiates a "developmental cascade" for cognitive abilities, such as reading and math. Motor skills are closely connected with the development of spatial cognition, an ability that supports deductive reasoning. Despite the…

Background: Strong associations between infant vocabulary and school-age language and literacy skills would have important practical and theoretical implications: Preschool assessment of vocabulary skills could be used to identify children at risk of reading and language difficulties, and vocabulary could be viewed as a cognitive foundation for…

Variability in achievement across learners is a hallmark of second language (L2) learning, especially in academic-based learning. The Twins Early Development Study (TEDS), based on a large, population-representative sample in the United Kingdom, provides the first opportunity to examine individual differences in second language achievement in a…