Inconsistency, Loose Construing and Schizophrenic Thought Disorder

¹ Psychology Department, De La Pole Hospital, Willerby, E. Yorks.
² Psychology Department, The University, Hull, E. Yorks.

1. It is suggested that the repeatedly confirmed finding of low intensity (of relationships between constructs) scores in thought-disordered schizophrenics, which Bannister has taken as the basis for his `loosened construction' theory of schizophrenic thought disorder, is in fact an artefact of the contamination of intensity scores by inconsistency. There is some support for this alternative hypothesis in the literature, since it has been found in eleven studies that consistency scores tend to be positively, and usually significantly, correlated with intensity scores, and to discriminate thought-disordered schizophrenics from other groups about as well. However, this evidence is not conclusive, since there is also the possibility that consistency scores are contaminated by intensity, as well as the other way round.

2. To overcome this difficulty, a form of repertory grid test was administered to ten thought-disordered schizophrenics, ten non-thought-disordered schizophrenics and ten normal controls, in which the subjects ranked various overlapping subsets of elements, rather than, as is conventional, the whole set, thus making possible a measure of pure internal consistency. Although intensity scores significantly discriminated the thought-disordered schizophrenics from the others, pure internal consistency scores (which were significantly correlated with them) did so better and when pure internal consistency was partialled out of the intensity scores, the latter no longer discriminated the groups significantly. Effectively identical results have been obtained by Frith and Lillie.

3. It is shown that the phrase `loosened construction' has been used in two different senses, consistency (Kelly) and intensity (Bannister). Thus the results give no confirmation to Bannister's theory, but strongly support the idea that schizophrenic thought disorder is characterized by loosened construing, in Kelly's sense.