Implicit vs. letter-by-letter reading in pure alexia: A tale of two systems

Recent studies of pure alexia present a contradictory picture. Despite evidence of impaired letter identification in letter-by-letter readers, some patients are able to carry out lexical decision and other tasks under conditions of rapid presentation, although they are seldom able to identify these stimuli explicitly. We review evidence for both facets of pure alexic performance and offer an account of this pattern in terms of right- and left-hemisphere reading mechanisms. Specifically, we suggest that the right hemisphere supports performance in covert reading tasks, and that letter-by-letter reading is the product of the left hemisphere, operating on information transmitted from the right.