The shifting role of fluid reasoning in reading among children evaluated for ADHD

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.