Poster #5 - Child Vocabulary and Developmental Patterns of Growth in Executive Functions During Toddlerhood

• In Event: Poster Session 09

Abstract

Executive functions (EF) are the set of high-order cognitive processes involved in the voluntary control of thoughts, emotions, and actions (Moriguchi et al., 2016). EF combines several cognitive skills that are crucial for children's social and school adaptation, such as working memory, cognitive flexibility, and inhibitory control (Diamond, 2013; Zelazo, 2020). EF skills emerge in infancy and typically become more efficient throughout childhood into early adulthood (Korzeniowski et al., 2021). However, longitudinal studies using repeated measures of EF are scarce, especially during the first years of life. This dearth of research dramatically limits our understanding of the normative development of EF skills and precludes the identification of the factors that may promote or hinder this development, which is of critical importance for children’s daily functioning. The present study tackled this gap in the literature by modeling intra-individual developmental patterns of growth in child performance on three tasks measuring different EF skills between 12 and 24 months (objective 1), and by examining the capacity of early language skills, one of the most documented predictors of child EF (Diamond, 2014), to predict individual differences in these growth patterns (objective 2). Developmental improvements in child EF were expected. Toddlers with better language skills were also expected to show consistently superior EF performance across time.

The sample consisted of 145 children met at home at 12, 18, and 24 months. Children's emerging language skills were measured with the MacArthur Communicative Development Inventory (MCDI; Fenson et al., 2007), a parental report on children's expressive and receptive vocabulary. EF were measured using three tasks: Hide and Seek (working memory, Garon et al., 2014), Reverse Categorization (cognitive flexibility, Carlson et al., 2004) and Prohibition (inhibitory control, Friedman et al., 2011).

To describe patterns of growth in EF between 12 and 24 months, multilevel growth curve analyses were carried out. Results are presented in Table 1. The best-fitting growth models indicated a significant monthly increase in performance on the three EF tasks across time. There was no variability around the rate of change for all EF, indicating homogenous growth in these skills. However, there was significant variability around the initial status for cognitive flexibility and working memory, indicating inter-individual differences in baseline performance scores. To meet the second objective, child receptive and expressive vocabulary were next entered as predictors into the growth models while accounting for child gestational age. Findings of the predictive growth models are presented in Table 2. Child receptive vocabulary was found to be a significant predictor of child cognitive flexibility, while expressive vocabulary predicted inhibitory control and cognitive flexibility. Hence, children with better receptive vocabulary skills showed consistently superior performance on the cognitive flexibility task across time, while children with better expressive skills demonstrated greater cognitive flexibility and inhibitory control skills across time. This study provides insights into how each EF develops during toddlerhood and how emerging vocabulary skills are related to this important development.

Authors

• Frederic Theriault-Couture, Laval University
  Presenting Author

• Julien Massicotte

• Célia Matte-Gagné, Laval University