Schizophrenic patients exhibit hyper-reflexivity in a semantic categorical priming task

Semantic priming is a phenomenon that occurs when a semantically related ‘‘prime’’ word produces a faster response time to a sequentially presented ‘‘target’’ word than if they were semantically unrelated. This process of priming is thought to involve two distinct processes, one that is reflexive and unconscious, and the other, which is voluntary and intention-driven. It is believed that a dysfunction in one or both of these processes may result in the pattern of thought disorder in schizophrenia. In an attempt to better understand disorganized speech and thought disorder, we examine language processing in schizophrenia by separately studying reflexive and voluntary priming processes using a lexical decision semantic priming task, that is similar to the landmark study with controls by Neely [(1977). Semantic priming and retrieval from lexical memory: Roles of inhibitionless spreading activation and limited-capacity attention. Journal of Experimental Psychology, 106, 226–254]. In two experiments, we tested a total of 40 schizophrenic and 40 control subjects. In both Experiments 1 and 2, schizophrenic subjects showed greater semantic priming than control subjects in the reflexive task condition, demonstrating that they seem to exhibit excessive priming of the semantic network. On the other hand, in our study, there were no differences in priming between schizophrenic and control subjects in the voluntary task condition. These results support the idea of a dysfunction in the reflexive system (hyper-priming) as a core deficit in language processing in schizophrenia. r 2006 Elsevier Ltd. All rights reserved.