Contribution of visual and semantic proximity to identification performance in a viral encephalitis patient

Identification deficits were investigated in F.S, a patient with herpes sim plex viral encephalitis. F.S.'s confrontation naming abilities were assesse d for multiple repetitions of 12 line drawings of artifacts. Six of the lin e drawings consisted of psychologically "close" objects (i.e., objects that share many visual and semantic features with other objects) and 6 were psy chologically "disparate" objects (i.e., objects that share few, if any, vis ual and semantic features with other objects). F.S. correctly named all of the objects from the "disparate" category but only 47% of the objects from the "close" category. We also tested F.S. using novel, computer-generated s hapes that were paired with artifact labels. We paired semantically close o r disparate labels to shapes and F.S. attempted to learn these pairings. Ov erall, F.S.'s shape-label confusions were most detrimentally affected when Lye used labels that referred to objects that were visually close and seman tically distinct. Results indicate that, at least for our patient, visual s imilarity contributed the most to his identification errors. (C) 2001 Acade mic Press.