Valdois, S.
CNRS
The VA span theory of developmental dyslexia posits that a subset of dyslexic readers show a reduction of the visual attention span, i.e. a reduction in the amount of visual information that can be processed in parallel. This deficit results in an inability to process multi-letter units (from graphemes to words) with detrimental effects on fluent reading. We will first review behavioural evidence for a VA span deficit in DD, with emphasis on the cross-language relevance of the theory and evidence for a causal relationship. We will present recent computational developments of the VA span theory to better understand the way sensory evidence, crowding and visual attention interact during letter string processing. Beyond the psychological and computational description of the VA span theory, neuro-imaging studies have identified the superior parietal lobes as the neural correlates of the VA span. These findings question current conceptions of the neural system of reading. We will discuss the implications of these cognitive and neuroimaging findings for the development of a neurocognitive model of reading acquisition.