VISUAL AND PHONOLOGICAL PROCESSES IN POOR READERS WORD RECOGNITION

In two experiments, poor and normal Dutch readers, matched for reading age, were presented with visual matching tasks on a computer screen. In Experiment 1, word and pseudoword letter strings were used. The str ings consisted of either uppercase/lowercase congruent (e.g., o/O) or uppercase/ lowercase incongruent letters (e.g., a/A). Poor readers nee ded significantly more time to decode uppercase/lowercase incongruent pairs, especially when the pairs consisted of pseudowords. Experiment 2 investigated whether this effect was phonologically or visually medi ated. Strings of letters, digit strings, and abstract figure symbols w ere used. Letter strings included words, pseudowords, and nonwords. Po or readers needed more time to match incongruent letter case pairs, co nsistent with Experiment 1. Poor readers performed more poorly on lett er and digit string matching but not on the figure-symbol matching tas k. No evidence was found for the differential use of orthographic info rmation in terms of multiletter constraints. The combined data on the letter, digit, and graphic symbol matching experiments suggest that an inadequate command of grapheme-phoneme associations is a critical fac tor in reading disability. Evidence for poor visual processing as an i ndependent source of reading disability could not be established.