The present study aimed to investigate whether a brief reasoning
training module changes the ‘‘jumping to conclusions’’
data gathering bias in people with delusions. A
secondary aim was to examine whether improvements in
reasoning would lead to greater flexibility in thinking about
delusions. It was found that people with delusions and a diagnosis
of schizophrenia (n 5 34) requested less information
on a reasoning task compared with a nonclinical
control group (n 5 34). The clinical group was then randomly
allocated to a session of reasoning training or to
an attention control condition. Following training, participants
showed a significant increase in data gathering, and
a small number reported more flexibility and less conviction
in their delusions, although this finding was not significant.
The presence at baseline of an extreme reasoning bias moderated
the effect of training. The study provides further
confirmation of the jumping to conclusions bias and shows
that data gathering can be improved, though the severest
form of the bias is resistant to change. It is recommended
that lengthier, delusion-related reasoning packages be developed
and evaluated.