Two experiments on the relation between psychoticism and response uncertainty in normal subjects

Previous studies have suggested that schizophrenics are affected by response uncertainty to a greater degree than normals or other psychiatric groups. Two studies examined whether a similar pattern of performance would be produced in normal Ss scoring high on questionnaire measures presumed to measure psychotic predisposition. The Psychoticism (P) scales from the EPQ and the unpublished PEN Inventory were employed; and response uncertainty was varied using a card-sorting procedure. In Experiment 1 males were more affected by increases in response uncertainty than females, but there was no difference between Ss scoring high and low on the P scales. Experiment 2 included a condition in which guide-cards were randomly reordered between trials. There was a highly significant tendency for Ss scoring high on the PEN P scale to be more affected by response uncertainty in this experiment. Again males were more influenced by uncertainty than females, but this was due largely to their performance under the condition where guide-cards were varied. Ss high on EPQ P also showed decremental performance under this condition. The data provided partial support for the validity of the P scales, particularly the PEN version of the scale, as indices of schizophrenic predisposition.