Two studies of conceptual rule-learning by 36 hospitalized psychiatric patients revealed that (a) while all were clinically diagnosed as schizophrenic, they differed widely in their ability to discover abstract rules; (b) the Whitaker Index of Schizophrenic Thinking (WIST) strongly predicted the patients' ability to learn and to apply a conceptual rule; and (c) regardless of severity of conceptual impairment, the patients were unaffected by modest levels of externally generated irrelevant information as presented through the modality of vision. Deficits in abstractive ability, when they exist, are believed to be due to a schizophrenic patient's inability to prevent task-irrelevant information that originates in long-term memory from spilling into and despoiling the operations of working memory.

Literature that addresses the diagnosis of mental disorder in adolescents strongly suggests that it may not be possible to do so. Schizophrenic thinking, in particular, has been seen as generally characteristic of adolescents. Making judgments of specific responses from the Rorschach, the WAIS, and the WIST, 10 expert clinicians were able to make judgments with regard to 12 adolescents in the 16–19 age range that were suprisingly accurate in discriminating among schizophrenics, nonschizophrenic hospitalized adolescents, and a normal control group. Results indicate that schizophrenic thinking is not necessarily characteristic of adolescents and that information from the WIST may be helpful in identifying schizophrenic adolescents.

Four articles that reported studies that used the Whitaker Index of Schizophrenic Thinking (WIST) were published in the Journal of Clinical Psychology in early 1977. These articles are reviewed by the WIST's author in terms of necessary conditions for valid and useful studies of schizophrenic thinking. Two of the studies reported used the MMPI Sc Scale: one of them failed to note its limitations and used the WIST incorrectly; the other resulted in some useful data. The other two articles report ground-breaking investigations of schizophrenic thinking as conceptual rule-learning inability. They are viewed as providing a valuable new orientation in the study of schizophrenic thinking because they investigate the phenomena first-hand instead of relying simply on ordinary psychiatric diagnosis for a criterion. Some previously unpublished data on the WIST and intelligence relevant to all four studies are reported.

No abstract

No abstract