Specificity of the jump-to-conclusions bias in deluded patients


Correspondence should be addressed to Dr Emmanuelle Peters, Department of Psychology (PO77), Institute of Psychiatry, Henry Wellcome Building, De Crespigny Park, London SE5 8AF, UK (e-mail: e.peters@iop.kcl.ac.uk).



To investigate the specificity of the ‘jump-to-conclusions’ (JTC) bias in delusions.


Thirty-seven psychotic patients were divided into two separate groupings: (1) deluded versus non-deluded individuals and (2) individuals with and without a diagnosis of schizophrenia. Groups were compared on three reasoning tasks (‘Beads’ task, Wason's 2–4–6 task, and Wason's selection task).


Deluded participants had a tendency to show a JTC bias on data-gathering tasks, but no differences were found with the schizophrenia diagnosis grouping. There were no differences between any groups on tasks of general reasoning and probability judgments.


The results suggest that JTC is specific to delusions rather than diagnosis, and to data gathering rather than a general deficit in reasoning.