Verb semantics in aphasia: truly categorial effects or artifacts?

Verb semantics in aphasia is the central issue of this paper. Elsewhere (Finocchiaro, 1999; Finocchiaro e Miceli, in preparation) new evidence for the categorial organization of verb knowledge in the brain has been reported. Here, two single-case studies, seemingly showing actional and/or 'purely semantic' (i.e. non actional) category-specific deficits are presented. However, on closer analysis, the categorial interpretation of the observed dissociations was implausible, and due to the effect of other variables. Although not denying the psychologycal relevance of the actional classification, these data suggest that heterogeneous factors, such as morphological complexity, syntax and semantics (in a broad sense) can often determine category-like effects.