Responses of paranoid and nonparanoid schizophrenics in a dichotic listening task.

Differences in attentional processes between normals, paranoid schizophrenics, and nonparanoid schizophrenics were studied by delivering dichotically presented digits for identification. Thirty paranoid schizophrenics (20 acute and 10 chronic), 30 nonparanoid schizophrenics (20 acute and 10 chronic), and 20 normal controls were tested. The data were analyzed in terms of the overall level of correct identification of stimuli presented to the two ears, the number of shifts in report from one ear to the other, and the magnitude of ear differences in recall. The results showed that overall level of performance was higher for the normals than for the schizophrenics; the number of ear shifts was greater for normals and nonparanoid than for paranoid schizophrenics; and ear differences were biggest for the paranoid schizophrenics and smallest for the normals. The results were interpreted in terms of differences in attentional style and rate of information processing.