Publication Date


Document Type


First Advisor

Martin, Randall B.

Degree Name

M.A. (Master of Arts)

Legacy Department

Department of Psychology




The literature on conceptual overinclusion in schizophrenia is reviewed. Studies in this area are critiqued in terms of their measures of overinclusion, and the lack of attention paid to the possible confounding -variables of stimulus affectivity and complexity Some studies exploring the effects of stimulus affectivity and complexity on other aspects of schizophrenic performance are considered in order to demonstrate the importance of these variables. The purpose of the study reported was to assess the relative overinclusiveness of affective and nonaffective concepts by schizophrenics when stimulus and task complexity were controlled. A paper- and-pencil measure of overinclusion, extensively modified for this study and which is presumably a more faithful operationalization of overinclusion than more commonly-used measures, is described. Ten chronic schizophrenics, ten acute schizophrenics, and ten nonpsychiatric medical patients each completed the affective and the nonaffective measures of overinclusion. Schizophrenics were more overinclusive than nonpsychiatric patients. Among schizophrenics, chronics were more overinclusive than acutes, delusional schizophrenics more overinclusive than nondelusional schizophrenics, and schizophrenics with poor premorbid adjustment more overinclusive than those with good premorbid adjustment. Among schizophrenics there was also relatively more affective than nonaffective overinclusion. The possible relevance of conceptual overinclusion to schizophrenic symptomatology is discussed, and an information-processing theory of schizophrenia is briefly outlined. According to this theory, the locus of the schizophrenic's conceptual deficit is in long-term memory. Overinclusive concepts or prototypes in long-term memory are hypothesized to result in attentional deficits, faulty affective pattern recognition, and thought disorder.


Includes bibliographical references.||Includes illustrations.


viii, 111 pages




Northern Illinois University

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