PERCEPTUAL AND LEXICAL FACTORS IN A CASE OF LETTER-BY-LETTER READING

We report the case of a letter-by-letter reader (MJ) who showed normal processing of single letters and who could normally access the orthog raphic input lexicon when presented with letter names for aural recogn ition, or when allowed enough time to process a visually presented let ter string. However, MJ showed severe difficulties in simultaneously p rocessing multiple letters and other simple visual stimuli. Furthermor e, she does not have normal access to lexical orthographic representat ions and their meanings when stimuli are presented for too brief a tim e to allow for serial processing of the letter string. We found no evi dence of (partial) lexical or semantic access without corresponding re cognition of the letters in a word: No signs of implicit reading were observed when the input stimuli were controlled for the relevant visua l features; ''implicit reading'' was only obtained under conditions th at allowed sophisticated guessing. This pattern of results is interpre ted as indicating that LBL reading (at least in MJ) results from damag e to prelexical processing mechanisms. In MJ's case, the deficit refle cts the degraded transfer of information from a normal visual processi ng system in the right hemisphere to a normal language processing syst em in the left hemisphere.