Psychological Distance of Semantic Categorization in Schizophrenia

Abstract

This study aimed to examine the psychological distance of categorization in schizophrenia. A cross-sectional design was adopted with a total of 187 patients with schizophrenia and 98 normal controls. Participants were asked to generate as many exemplars from within a semantic category as they could in 3 minutes. The categories selected for this study were “Animal”, “Means of Transport”, “Food” and “Furniture”. Analysis using the Rasch Model was undertaken. The findings indicated that the psychological distance, in terms of logits unit, was not at an equal interval within each category across the 3-min interval in both patients and healthy controls. The psychological distances between different categories were also found to be inconsistent in both groups. These preliminary findings suggest that we should not simply equate different category scores when we study semantic categorization. Such a simple “count” of categories may not sufficiently reflect the actual psychological distance perceived by patients and healthy controls. Future study should further examine a more representative and accurate measurement of semantic categorization.