Concrete and abstract word processing in deep dyslexia

Abstract

Abstract The purpose of this case study was to test the failure of inhibition theory of deep dyslexia (FIT; Buchanan, McEwen, Westbury, & Libben, 2003) with concrete and abstract words. FIT proposes that in deep dyslexia, errors to abstract words are the result of an impairment in phonological output lexicon selection rather than a semantic deficit for abstract words. FIT also proposes a dissociation between explicit phonological lexicon production (can be compromised) and implicit access of representations (is intact). With such assumptions it follows that in phonologically implicit tasks where controls demonstrate either concreteness or abstractness effects, a participant with deep dyslexia would similarly show concreteness or abstractness effects. However, for explicit tasks where production is involved, a participant with deep dyslexia would only show concreteness effects due to difficulty with abstract word production, indicative of their difficulty with phonological output lexicon selection which is more compromised for abstract words because semantic content cannot guide the selection. Experiments 1–3 used phonologically implicit tasks (i.e., concrete categorization task, semantic relatedness task, and iconicity judgment task) and Experiment 4 used an explicit task (i.e., oral word-reading task). The results supported the hypotheses and are consistent with FIT as an explanation for the locus of impairment in deep dyslexia.