Reactions to ambiguous stimuli among paranoid personalities

The psychological literature on paranoia and paranoid schizophrenia is extensive, particularly in the area of perceptual and cognitive processing. However, there has been a relative neglect of paranoid personality. The present study investigates whether paranoid personalities differed from controls in their responses to ambiguous or incomplete stimuli. Paranoid personalities (PP), other personality controls (OP), and normal subjects (NR) were exposed to blurred pictures of zoo animals which became progressively clearer. Subjects were asked to identify the content of such pictures from a list provided and to rate their confidence in their respective identifications. The PPs were unique in suspecting that correct answers were not provided by the experimenters. The confidence levels of the PPs also decreased significantly during the course of the experiment, whereas the OP and NR subjects' levels did not. The PP group made significantly earlier attempts at identifying the ambiguous slides and were significantly more accurate in doing so compared to the NR group. Neither group differed significantly from the OR controls on these two measures. The significance of the results are discussed.