Word learning and the cerebral hemispheres: from serial to parallel processing of written words

摘要

Reading familiar words differs from reading unfamiliar non-words in two ways. First, word readingis faster and more accurate than reading of unfamiliar non-words. Second, effects of letter length arereduced for words, particularly when they are presented in the right visual field in familiar formats.Two experiments are reported in which right-handed participants read aloud non-words presentedbriefly in their left and right visual fields before and after training on those items. The non-wordswere interleaved with familiar words in the naming tests. Before training, naming was slow anderror prone, with marked effects of length in both visual fields. After training, fewer errors weremade, naming was faster, and the effect of length was much reduced in the right visual fieldcompared with the left. We propose that word learning creates orthographic word forms in themid-fusiform gyrus of the left cerebral hemisphere. Those word forms allow words to access theirphonological and semantic representations on a lexical basis. But orthographic word forms alsointeract with more posterior letter recognition systems in the middle/inferior occipital gyri, inducingmore parallel processing of right visual field words than is possible for any left visual field stimulus,or for unfamiliar non-words presented in the right visual field.