Poster #107 - A Longitudinal Study of the Relationship Between Vocabulary Structure and Word Learning

• In Event: 3-206 - Poster Session 13
  In Poster Session: PS 13 Section - Language, Communication

Integrative Statement

In typical development, word learning goes from slow and laborious to fast and seemingly effortless. This is not the case for children below the 20th percentile on productive vocabulary (late talkers), who in addition to lagging in their vocabulary size, do not seem to show the same word learning biases that typically developing children do (Jones, 2003), namely attending to the shape of solid objects and the material of nonsolids. Previous work has shown a correspondence between vocabulary structure and word learning biases in typically developing children (Perry & Samuelson, 2011) and the noun vocabularies of late talkers and typically developing children differ structurally (Beckage, Smith & Hills, 2011; Colunga & Sims, 2017). We set out to explore the interplay between vocabulary structure and word-learning biases of late-talker and typically-developing toddlers in three longitudinal cohorts, looking at vocabulary data from toddlers as reported by their parents and at the way these toddlers learn new words in the lab. Here we examine the longitudinal relationship between vocabulary and word learning, focusing on the stability and change of children’s vocabulary scores over time. Understanding the factors that shape word learning trajectories may help us predict outcomes and design interventions.

Study 1. Thirty-four 18-month-olds – including 10 late talkers (bottom 20th percentile in the Macarthur-Bates Communicative Development Inventory (CDI), a normed checklist of over 600 early words) came to the lab monthly for a year. At each visit, parents completed a CDI for their child and children completed a novel noun generalization task to measure their word learning biases. Despite an initial normal distribution on the CDI, at the 12th visit 64% of children scored above the 90th percentile. Follow-up measures at 6 and 12 months post-study indicated persistent above average performance on a different set of parent- and child-based language measures (see Table 1). We attempted to disentangle the possible causes of this finding with two more longitudinal cohorts, and cross-sectional controls.

Study 2. The 2nd and 3rd cohorts included 79 children (33 late talkers; recruitment prioritized late talkers). Procedures during the initial 12 months of the study were the same as the first cohort. An additional 47 36-month-olds and 28 42-month-olds were recruited as cross-sectional controls. Both groups were tested on language and cognitive measures: Peabody Picture Vocabulary Test (PPVT), Expressive Vocabulary Test (EVT), working memory, and executive regulation tasks. Despite the fact that late talkers were overrepresented in the longitudinal group, scores on PPVT, but not EVT were higher for longitudinal than cross-sectional participants (see Table 2). The fact that working memory and material bias scores for nonsolids were also higher for the longitudinal group, suggests a possible mechanism of change.

Hierarchical modeling suggests differences in the role of word learning biases and other cognitive factors in predicting vocabulary size for late talkers versus typically developing children. We discuss the possible causes for the unexpected finding of overall language improvement in the longitudinal participants, and implications for intervention in late talkers and vocabulary enrichment for typically developing children.

Authors

• Jennifer Weber, University of Colorado-Boulder
  Presenting Author

• Eliana Colunga, University of Colorado-Boulder
  Non-Presenting Author