Chapman's versus Broen and Storms' theory of schizophrenic thought disorder: an empirical comparison

Compared Chapman's "response-bias" theory and Broen and Storms' "response-disorganization" theory of schizophrenic psychological deficit in a combined experimental format. Twenty-six hospitalized schizophrenics and 26 normal Ss, equivalent in age, education, and WAIS vocabulary, were administered a modification of Roberts and Schuhams' (1974) vocabulary sorting task. Ss chose a word conceptually similar to a referent from correct, moderate- or strong-distracter, and irrelevant responses. Half of the participants performed under induced muscular tension (squeezing a hand dynamometer). Results indicated that, congruent with Broen and Storms' theory, heightened arousal increased frequency of nondominant, strong-distracter errors in normals, but did not affect moderate distracter selection. No significant arousal effects emerged in the schizophrenics. The patient group essentially performed according to Chapman's theory, making significantly more strong- than moderate-distracter errors under both conditions. Rank orders of normal and schizophrenic errors did not differ significantly. Implications are discussed.

Cognitive functioning in schizophrenia. I. Stimulus analysing and response selection processes

It has long been accepted that inadequate or abnormal cognitive performance is a characteristic of those patients described as schizophrenic (Cameron, 1938, 1939; Goldstein, 1939). A number of theories have been advanced to suggest that the basic deficit underlying this abnormal performance lies in impaired information processing. McGhie (1969, 1970) and Payne (1960) consider the defect to be in the filter that normally operates to exclude irrelevant stimuli, while Yates (1966a, 1966b) suggests that the impairment may reflect a slowed rate of information transfer in the primary processing channel. Hawks and Marshall (1971) also argue for slowed processing, but although they talk about overload due to inappropriately filtered input they appear to identify their position with Broen's (1968) response interference theory.