Are verbs like inanimate objects?

One of the most compelling findings in aphasic research is that neurological impairment may affect words of one grammatical class more than others, for instance, verbs more than nouns (e.g., Miceli, Silveri, Villa, & Caramazza, 1984; McCarthy & Warrington, 1985) or vice versa (e.g., Bates, Chen, Tzeng, Li, & Opie, 1991; Zingeser & Berndt, 1988). The underlying mechanisms of such grammatical dissociations are controversial. Bird, Howard, and Franklin (2000) recently proposed a model attributing the noun/verb dissociation to the conceptual system, based on the influential sensory/functional theory (SFT) (e.g., Warrington & McCarthy, 1987). SFT assumes that concepts are represented in the brain by different types of features, such as sensory and functional ones; the concepts of animate things have higher proportion of sensory features than the concepts of artifacts (inanimates) do, and artifacts have higher proportion of functional features than animates do. Damage to sensory features will result in more severe deficits to animates, and vice versa. Bird et al. (2000) extended SFT to the domain of verbs, proposing that the sensory-to-functional ratios for verbs are even smaller than that for artifacts. They further argued that a deficit in the processing of nouns may be attributed to damage of the sensory features. An important prediction made by this theory is that patients who exhibit a noun deficit should also be more impaired with animates than with artifacts within the noun domain. Here, we report a case that allows a direct test of the central prediction of this theory. Our patient, ZBL, was more impaired in noun-naming than in verb-naming, but was better with animates than with artifacts.