Schacter et al. (1990)
found support for a functional dissociation between visual and auditory priming effects in a letter-by-letter reader. Their conclusions were based on the perceptual representation systems framework, suggesting that visual priming is mediated by a visual word form system separate from an auditory word form system responsible for auditory priming. This article focuses on visual and auditory priming effects exhibited by poor readers with phonological or surface subtypes of reading disability. The phonological type of reading disability was defined as an impairment in phonological word decoding, whereas the surface type of reading disability was defined as an impairment in orthographic word decoding. The results demonstrated a double dissociation, such that poor readers with a surface type of reading disability produced more auditory than visual priming, whereas poor readers with a phonological type of reading disability showed more visual than auditory priming. The majority of children with reading disabilities showed weaknesses in both orthographic and phonological word decoding and, importantly, low levels of priming effects for both visually and auditorily presented materials. Finally, age-matched normal readers showed significant priming effects for both visual and auditory presented words. These findings support the assumption that both orthographic and phonological skills can be simultaneously impaired and that a dual-route model for the acquisition of word decoding skills might be the most appropriate framework to describe different subtypes of reading disabilities. 1998 John Wiley & Sons, Ltd.