Links Between Executive Functions and Decoding Skills in a Semitransparent Orthography: A Longitudinal Study from Kindergarten to First Grade.

Abstract

Despite progress in understanding the link between executive functions (EFs) (i.e., a set of skills involved in goal-directed activities crucial for regulating thoughts and actions) and word decoding skills, research has not yet determined the dynamics and extent of this link. This longitudinal study examined whether EF subcomponents (inhibition, working memory, and cognitive flexibility) significantly predict decoding skills in Portuguese, which has a semitransparent orthography. The sample included 81 children (M_age = 5.36 years, SD_age = 0.30; 40 girls) in their final year of kindergarten. EF performance was evaluated during kindergarten using nonverbal performance-based tests, and decoding skills were assessed one year later in first grade through a pseudoword reading task. A three-step regression analysis was used to explore the unique contributions of each EF subcomponent to decoding skills. Findings indicated that inhibitory control skills were significant predictors of first-grade decoding outcomes. However, adding working memory abilities to the regression model did not increase the explained variance. In the final step, including cognitive flexibility skills reduced the significance of inhibitory control and increased the amount of explained variance. These results suggest that, while inhibitory control plays an important role, cognitive flexibility has a more significant impact on word decoding skills, highlighting the importance of early development of specific EFs for decoding abilities.