Visual target detection is not impaired in dyslexic readers

In two previous studies we assessed a difficulty of dyslexic readers with letter string processing by using variants of the partial report paradigm, e.g., Averbach and Coriell [Averbach, E., & Coriell, A. S. (1961). Short-term memory in vision. Bell Systems Technical Journal, 40, 309-328] which requires report of a letter name in response to a position cue. The poor dyslexic performance was interpreted as evidence for a visual-attentional deficit of dyslexic readers. In the present study, we avoided verbal report by using a task which only required the detection of predefined targets (letters or pseudoletters) in strings. On this purely visual task, the dyslexic readers did not differ from non-impaired readers. This finding speaks against a basic visual-attentional deficit; rather it suggests that the dyslexic deficit on partial report paradigms stems from a problem in establishing a string representation which includes position and name codes.