Executive Function and Sentence Processing Ability: Evidence from the Language 0-5 Project

There is a wealth of evidence demonstrating that executive function abilities (EF) are positively, and significantly, associated with language development during the preschool years, such that children with good executive functions also have larger vocabularies and faster language development. However, why this is the case remains to be discovered. In this paper, we focus on the hypothesis that sentence processing abilities mediate the association between EF skills and receptive vocabulary knowledge, in that the speed of language acquisition is at least partially dependent on a child's processing ability, which is itself dependent on executive control. We test this hypothesis in longitudinal data from a cohort of three- to four-year-old children at three ages (36, 42 and 48 months). We find evidence, consistent with previous research, for a significant association between three EF skills (cognitive flexibility, working memory and inhibition) and receptive vocabulary knowledge across this age range. However, critically, only one of the tested sentence processing abilities (the ability to maintain multiple possible referents in mind) significantly mediated this relationship, and only for one of the tested executive functions (inhibition). The results suggest that children who are better able to inhibit incorrect responses are also better able to maintain multiple possible referents in mind while a sentence unfolds, a sophisticated sentence processing ability which may facilitate vocabulary learning from complex input.