Children with attentional difficulties are more likely than their peers to experience challenges in basic reading skills, including phonemic decoding and word recognition. Such challenges may require reliance on higher-order cognitive functions such as fluid reasoning (Gf) to attain reading proficiency. The present study sought to clarify the role of Gf in phonemic decoding and word recognition among children-in grades 1-7 (n = 156)-being evaluated for attention-deficit/hyperactivity disorder (ADHD). Effects of Gf were examined in relation to crystallized knowledge (Gc). Results indicated that Gf exerted a direct effect onto phonemic decoding in early grades (grades 1-2) but not in later grades (grades 3-7). Gf also exerted an indirect effect onto phonemic decoding-through Gc-in later grades (grades 3-7) but not in early grades (grades 1-2). Finally, Gf exerted an indirect effect onto word recognition through phonemic decoding in grades 1-4 but not in grades 5-7. Altogether, findings show that Gf plays a direct role in younger children's phonemic decoding and an indirect role in word recognition (through Gc) in later grades, suggesting a shift in Gf's role across grade levels. Although findings need replication in longitudinal research, current results have implications for both typical and atypical reading development.
Keywords: Attentional difficulties; cognitive development; crystallized knowledge; fluid reasoning; reading acquisition; word recognition.