What semantic errors restricted to either speaking or writing in aphasia tell us about lemmas

Theories about word production differ in whether they assume that lexical selection involves modality-specific representations or modality-neutral ones, called lemmas. The observation semantic errors aphasia may be restricted to either speaking writing has long been taken challenge lemma models (Hillis et al., Citation1999; Kemmerer, Citation2015, Citation2019). Whereas patients RGB, HW, and RR make but not writing, patient RCM exhibits the opposite dissociation. Here, using WEAVER++ simulations a simple mathematical analysis, model with lemmas is shown account for double dissociation observed patients. In particular, captures patterns of performance on vocal picture naming, written auditory comprehension, dictation, explaining 98% variance. now findings was designed explain first place.