The visual attention span theory ofdevelopmental dyslexia: the causality issue.Sylviane ValdoisCNRS and Université Grenoble AlpesSylviane.Valdois@upmf-grenoble.frIn her Nature Reviews Neuroscience paper,U. Goswami (2014) listed the challenges inestablishing causality for any theory of dyslexia.She argued that the visual attention (VA) spantheory lacked evidence in support of causality.The symposium will discuss the causality issue.Study 1 will focus on the reading level matcheddesign and cross language studies. Study 2 willreport supportive evidence from a longitudinalstudy and Study 3 from a training study. Study4 will present a new computational model thatmakes explicit how VA span reduction affectsletter-string processing.