The semantic organisation of mass nouns: Evidence from semantic refractory access dysphasia

The conceptual properties and organisation of mass noun concepts are examined in a patient (A.Z.) with a semantic refractory access disorder. A cardinal feature of this class of disorder is the build up of interference (refractoriness) between semantically similar concepts. In a series of written word identification tasks, a gradient of semantic relatedness is demonstrated within the broad domain of mass noun concepts but not between different word classes. More detailed examinations of semantic similarity effects within subcategories of mass concepts reveal a variable degree of fine-grain organisation, which may reflect the influence of premorbid personal knowledge and experience. Furthermore, it is demonstrated that common mass or count noun status did not lead to an enhancement of the refractory effects of semantic similarity.