Discussion
The current study replicates the well-established data
gathering bias among people with delusions and a clinical
diagnosis of schizophrenia. The participants with delusions,
a group with long-term illnesses and persistent
symptoms, were selected to have high levels of delusional
conviction. They requested less information than the
nonclinical participants without delusions before making
a decision on both versions of the beads task. Over 50% of
the clinical sample jumped to conclusions compared with
a quarter of the nonclinical sample. However, this study
was an attempt to move beyond demonstrating an association
of delusions and reasoning by investigating whether
the data gathering bias can be modified and assessing the
consequent effect on thinking about delusions.
A brief, single session training intervention had an effect
on data gathering, reflected in a significant increase
immediately after training in the number of beads
requested on both versions of the beads task. The study
therefore demonstrates that it is possible to change the
data gathering of people with delusions, in the short
term. The change was greater on the 60:40 version of
the beads task. Why was there a difference in training
effects on the 2 tasks? It could be that the training was
only weakly effective, or it might be explained by the level
of difficulty of the 2 tasks. The 85:15 task is much easier