COMPETITIVE-INHIBITION MODELS OF LEXICAL-SEMANTIC PROCESSING - EXPERIMENTAL-EVIDENCE

A modified Neisser word-search (search II) was administered to patient s with Parkinson's disease (PD), and significant deficits were found. Given the assumption that the processes are lexical, we interpret the results as support for the claim that there is competition between sem antically related words in speech production (Wheeldon, 1989). A relat ed verbal task-switching experiment (continuous series II) is also pre sented. Although PDs are impaired on task switching, there are double dissociations between verbal task switching (continuous series II) and lexical retrieval (search II). The relationship between performance o n these tasks and on verbal fluency is also addressed. (C) 1996, Acade mic Press, Inc.