Backward pattern masking of familiar and unfamiliar materials in disabled and normal readers

A discrimination task involving backward pattern masking was designed to investigate differences between disabled and normal readers in text perception. Masking was observed for both groups with unfamiliar Japanese materials, but disabled readers were less sensitive in discriminating than were normal readers. The same result was obtained with Roman letters, despite the high familiarity of materials to both groups, and with nonwords and words. A significant interaction between group and stimulus onset asynchrony, indicating that disabled readers recovered from masking at a slower rate than normal readers, was found only with nonwords. Visual factors alone could not have mediated group differences. A subgroup of disabled readers, formed on the basis of susceptiblity to masking, showed evidence of a deficit in rate of visual processing. The results are likely due to differences in the quality of representations of visual information used in discrimination and in word recognition.