Categorization in aphasia: Access and organization of goal-derived and common categories

This investigation examined aphasic adults' access and organization for goal-derived and common categories. Fluent and non-fluent aphasic subject groups and a group of non-brain-damaged controls participated in category verification and exemplar generation tasks. Although both groups with aphasia consistently required additional time to verify category examples for both types of categories, performance accuracy was similar for all three groups, regardless of category type. Both aphasic groups displayed difficulty accessing peripheral category examples for the common categories on exemplar generation. The results support recent suggestions that both fluent and non-fluent aphasic individuals retain partially normal semantic category information which is reflected in their appropriate production of central or in-set category examples; however, these adults present with impoverished representations of the boundaries around a category's referential field.