Title: Does IQ matter for the brain basis of reading skill?
Speaker: James Booth (Patricia and Rodes Hart Professor, Department of Psychology and Human Development, Vanderbilt University, USA)
Location: In Person & Online via Zoom
Abstract: Decades of behavioral research shows a bidirectional relation between the development of phonological awareness and reading skill. Longitudinal studies also show that the influence of intelligence on reading skill is mediated by phonological awareness. Neuroimaging studies emphasize that the difference between those with dyslexia and typical readers is similar regardless of a discrepancy with intelligence, however, these studies do report that some effects are moderated by intelligence. Moreover, these studies are plagued by relatively small sample sizes and do not treat skill as a continuous variable. To address these issues, we performed a mega-analysis through harmonization on our data shared on OpenNeuro of 4 cross-sectional datasets in 8- to 16-year-old children (N=364), making it the largest study ever to definitively examine the neural acquisition of reading. All datasets assessed activation in a visual word rhyming task during functional magnetic resonance imaging (fMRI). In behavioral analyses, we found that higher phonological awareness and higher fluid intelligence were related to better reading skill, with no moderation effects of intelligence. In region of interest neuroimaging analyses, we found that higher phonological awareness and better reading skill were related to greater activation in left ventral occipito-temporal, temporo-parietal and inferior frontal cortex, but there were no relations with or moderation effects of fluid intelligence. The whole brain analyses largely confirmed the region of interest findings showing that higher skill was related to greater activation of the reading network in regions implicated in orthographic, phonological and lexical processing. Whole brain analyses additionally showed that poor reading was associated with greater activation of occipito-parietal cortex suggesting overreliance on non-linguistic visuo-spatial attention. Although we did not find that the relation of skill to brain activation was moderated by intelligence in reading network, we did find moderation in regions implicated in visuo-spatial attention, particularly the lingual to precuneus, suggesting the brain basis of poor reading depends on intelligence. Our research informs multifactor neuro-cognitive models of reading acquisition and is relevant to the debate over whether the nature of the reading difficulties is fundamentally the same in children with dyslexia and whether they should respond similarly to intervention, regardless of a discrepancy with intelligence.
Website / BlueSky: