Category content and structure in schizophrenia: an evaluation using the instantiation principle.

In numerous studies, researchers have suggested anomalies in semantics in patients with schizophrenia. In this study, the authors addressed whether one such anomaly might reflect a difference in knowledge content or in the structure or organization of this information. Using a category member production task and a typicality rating task, the authors assessed knowledge content and found that patients' and control participants' knowledge about categories of foods and animals was very similar. In terms of structure, their findings from a mathematical model of category judgment (the instantiation model; E. Heit & L. W. Barsalou, 1996) revealed a similar category structure in patients and control participants. In conclusion, the authors suggest that the content and organization of categories in patients with schizophrenia is similar to that in healthy control participants. Copyright (c) 2005 APA, all rights reserved.