ABSTRACT
There are certain phenomena that appear sufficiently often in the reading and writing of individuals who have serious difficulties learning to read that clinicians have often considered them diagnostic of developmental dyslexia or specific reading disability. "Reversals" are probably the best known of these phenomena, including both static reversals-the confusion of mirror image letters such as b-d, and f-t in reading and writing-and kinetic reversals-the transposition of some or all of the letters within words so that was is read as saw and girl is written as gril. According to the clinical literature, although "these very same errors occur as the normal child learns to read; what distinguishes the dyslexic is the frequency and persistence of these errors well beyond the time at which they have become uncommon in the normal child" (Eisenberg, 1966, p. 15). In earlier years, these errors were accorded considerable attention in the literature because they were thought to provide evidence that reading disabilities are caused by some type of visual perceptual deficit. More recently however, compelling arguments have been made that reversal errors have a linguistic rather than a visual origin, and that there is little or no evidence of visual processing deficits among the reading disabled. The following quotations present a sampling of these current views:
Recent research strongly suggests that disabled readers can perceive letter and word symbols accurately, but mislabel them in oral reading because of a basic difficulty in associating symbols with their verbal counterparts. . . . The findings indicate that a child who calls b for d or was for saw in oral reading, can perceive these symbols but mislabels them in spite of accurate perception. This suggests that the child lacks verbal rather than visual information when he makes such errors, and
vich, 1992), the clinical phenomena associated with reversal errors have rarely been seriously discussed in the experimental literature since the time when Hinshelwood (1917) and Orton (1925, 1931, 1937) brought them to the attention of the scientific community. Thus the first section provides a brief discussion of reversal errors, from a clinical perspective, in the context of the development of reading and writing by children with reading disabilities or dyslexia. The second part presents a critical review of the empirical literature on reversal errors that may have implications for understanding the potential role of visual processing factors in reading/writing disabilities. Studies involving disabled and normal readers' processing of orientation information in perception/recognition and recall/reproduction tasks are reviewed under the rubrics of reversals of nonalphabetic stimuli, reversals of isolated letters, letter orientation errors in the context of nonwords, and letter orientation errors in the context of words. Finally, in a concluding section, limitations of the reversals literature are discussed and future research directions are proposed.
