Relationship between conceptual judgements and stimulus dimensions among schizophrenics and normals

Eighteen paranoid schizophrenics, 18 non-paranoid schizophrenics and 18 normal subjects were shown a set of 36 schematic drawings of human faces. The faces varied along four dimensions: nose length, chin length, distance between eyes, and forehead height. Subjects were asked to rate each face as either 'intelligent' or 'unintelligent' and then as either 'contented' or 'discontented'. The paranoid schizophrenics were less systematic than both the normals and non-paranoid schizophrenics in their use of the stimulus dimensions in the judgements, the latter two groups not significantly differing in this respect. It was also found that there were significant differences among the groups regarding the average importance given to the different physical features, the profiles for the two schizophrenic groups being flatter than that of the non-schizophrenics. The results suggested there were two aspects of consistency in dimension utilization involved in the overall group differences-between-subject and within-subject consistency. The paranoid schizophrenics displayed low within-subject consistency, the non-paranoid schizophrenics displayed a high within-subject consistency but low between-subject consistency (i.e. an idiosyncratic weighting of dimensions in their judgements), and the non-schizophrenics displayed high within- and between-subject consistency.