title: Processes underlying formal thought disorder in psychiatric inpatients.
abstract: Three theories about the cognitive processes underlying symptoms of formal thought disorder in psychiatric inpatients were tested. Chapman and Chapman's "excessive yielding to normal bias" theory and a response competition theory were tested by using two ambiguity tasks. Chapman and Chapman's bias theory predicts a smaller ambiguity effect for thought-disordered patients; a response competition hypothesis predicts a larger ambiguity effect. Results showed no difference between thought-disordered and non-thought-disordered patients. To test a distractibility theory of thought disorder, subjects performed a Stroop-type task in which they counted the number of digits (e.g., 3333) or symbols (####) in a set. Thought-disordered patients did show an increased effect of the presence of the digits, and this finding was replicated in a second inpatient sample. Thus, results were consistent with the distractibility theory and with a reformulation of the bias theory, in which the bias shown by thought-disordered patients is not a tendency toward a particular response, but rather toward a particular rule, or set, for responding.
mesh_terms: D000328:Adult; D001288:Attention; D003072:Cognition Disorders / Q000523:psychology*; D005260:Female; D006760:Hospitalization; D006801:Humans; D007845:Laughter; D008297:Male; D001523:Mental Disorders / Q000523:psychology*; D008960:Models, Psychological; D011581:Psychological Tests; D012565:Schizophrenic Psychology; D012718:Set, Psychology; D014705:Verbal Behavior