Apprehending schizophrenic discourse: A structural analysis of the Listener's task

Abstract

Characterizing aberrances specific to schizophrenic utterances, either purely in experiential terms or simply as features intrinsic to the language material itself, has demonstrated important limitations. Consequently, a model of listener interaction with text was pursued whereby constituent statements of discourse are organized on interpretation into hierarchal structures (or “bases”) according to their mutual presupposition relationships. “Coherence” was taken as the experiential signifier of a text base realization whose geometry conforms to a set of five conditions that collectively define “strong hierarchy” (SH). Violations of particular axioms yielded a typology of textual incoherence, referred to collectively as “non-strong-hierarchal” (NSH) discourse. In the experimental portion of the paper, determination of NSH discourse was found to classify speech samples randomly selected from a psychiatric population into schizophrenic and nonschizophrenic groups with a high degree of accurracy. Clinician responses to these same samples were studied. Classificatory accuracy of individual descriptive indices of “thought disorder” was found to be poor. Discriminant analyses for individual clinicians improved classificatory accuracy considerably. The two clinicians who retrospectively could be turned into the most powerful discriminators for schizophrenia also demonstrated the higher canonical correlations with the discourse analysis. These data suggest that clinician competence to a certain extent is modeled by the discourse analysis. The implications of these findings in terms of what is in the mind of the schizophrenic speaker were discussed, and a program for future research in this area was outlined.