Individual differences in the speed with which toddlers recognize spoken words predict overall vocabulary size both prospectively and retrospectively. However, the nature of the relationship between these variables remains unclear. First, it is unclear whether measurements of lexical processing speed reflect some central lexical or cognitive processing capacity or a set of word-specific processing speeds. These two accounts nicely map on two classes of structural equation models, effect- and causal- models. Second, it is unclear whether lexical processing speed predicts subsequent vocabulary over and above prior vocabulary, if vocabulary size predicts subsequent lexical processing speed over prior lexical processing speed, or both. In this talk, we address these two questions using data from a large longitudinal study on language processing from nine months to five years, called the Canberra Longitudinal Child Language project.
Presenter: Dr Seamus Donnelly is a Post Doctoral Research Fellow at the Research School of Psychology and the ARC Centre of Excellence for Dynamics of Language. He completed his PhD at the City University of New York Graduate Center in 2016. His research interests include language acquisition, with a particular focus on grammar, and statistical methods for language processing data.