On the nature of selective deficits involving nouns and verbs

In this paper we address the status of Verb-Noun (V-N) dissociation in aphasic patients, building on the results of a large-scale study (Luzzatti et al. 2002). We first briefly review the main positions that have emerged in the rich debate on this topic. We then reconsider the findings of Luzzatti et al. in light of such debate, offering a partially novel interpretation of their results. Our main (tentative) conclusions are the following. First, Luzzatti et al. do provide further evidence that V-N dissociations cannot be wholly explained in terms of extralinguistic aspects of our sensory/conceptual system. Second, such evidence can be accounted for, perhaps optimally, under the assumption that argument structure is what is involved in damage to verbs. Adamage to argument structure would, in fact, not only selectively affect verbs over nouns; it would also arguably determine the type of compensatory strategy to be used in such cases. In particular, the easier it is for an action to be coded in mental visual images, the easier it will be to restore the corresponding argument structure (by extracting from the events the corresponding theta-roles). Selective damage to nouns, on the other hand, cannot as readily be accounted for in terms of damage to argument structure and, in fact, it must be caused by different underlying mechanisms.