The process of work retrieval is studied in normal and aphasic subjects within the framework of a guiding model, using picture naming as the experimental paradigm. The initial studies use a lexical decision technique to probe for the earliest point at which evidence of phonological and semantic activation can be detected after perception of a pictured object. Our model predicts that phonological activity is concurrent with or even precedes semantic associations. The automaticity of name retrieval is explored in a non-naming situation. The time required for various levels of picture processing, from identity detection through name matching is to be examined by reaction time techniques to test predictions of our model in normals and subgroups of aphasic subjects. The response latencies associated with specified types of aphasic naming errors are to be compared with predictions derived from our model. A modification of the word-onset gating technique is to be used with aphasic and normal subjects to examine the interaction between word-stress and the location of the gated segment as cues to word recognition and word- retrieval. In our preceding work we found that aphasics approach normal competence in completing words on the basis of hearing word onset phonology. In this study we examine the hypothesis that the stressed syllable, regardless of position may serve as the starting point in the activation of word-phonology.
