Category specificity and feature knowledge:evidence from new sensory-quality categories.

Category-specific deficits and their relation to types of feature knowledge are addressed with respect to three semantic domains: artefacts, living things, and mass-kinds. The performance of a herpes encephalitic patient with a classic category-specific pattern of knowledge, MU, was compared to that of the other HSE patients and normal subjects. In a feature verification task involving over 4000 questions, MU showed a severe impairment with the mass-kind category, where his sensory features knowledge was at chance and much worse than his functional knowledge. In the feature production task, however, MU was grossly impaired with respect to sensory relative to functional features across all categories. Control experiments suggest that the deficits were of knowledge. Overall, these findings give some support to the sensory-functional theory, and are difficult to explain on the domain-specific knowledge theory. However, an account is still needed of the differences observed in MU's performance between the two paradigms.