Controlled information processing resources and the development of automatic detection responses in schizophrenia

The relation between resource limitations and the type of processing (automatic vs. controlled) on a multiple-frame search task (MFST) was examined in 15 schizophrenic and 15 normal control subjects. After 320 trials of consistently mapped practice, the patients' detection accuracy was normalized, and the effect of processing load (letter array size) on their detection accuracy was eliminated, which suggests automatization. Changes in load effects with practice could not be used as an index of automatization in control subjects, because of their unexpected lack of load effects at the beginning of practice. In a dual-task (MFST during auditory shadowing) condition after MFST practice, patients' MFST accuracy deteriorated nonsignificantly, and patients' shadowing declined significantly. The findings suggest schizophrenics have reduced available processing resources, but research is needed to determine whether this is due to abnormal automatization.