People who are prone to delusions make rushed decisions, according to a recent study.

Researchers from Royal Holloway at the University of London found that delusional people gather insufficient information before making decisions.

"People who suffer from delusions have unjustified, and sometimes bizarre, beliefs about themselves and the world. A tendency to gather insufficient evidence when forming beliefs, and making decisions, is thought to be a core cognitive component of delusion formation," researcher Ryan McKay said.

For the study, researchers assigned participants a computer task in which they observed the color of a black or white fish caught from one of two lakes and were then asked to choose to see further fish or decide on one of the lakes as the source of that sequence of fish. Each participant was rewarded for choosing the correct lake but costs were imposed for seeing more fish. In addition, the participants completed a questionnaire that measured how prone they were to delusions.

The results showed that the more delusion-prone the participants were, the earlier they chose a lake. Significantly, those who were highly prone to delusions chose a lake in advance of the optimum moment, gathering less information than they needed in order to make the decision that was most beneficial to them.

"In our study, the combination of rewards and costs created optimal decision points, allowing us to investigate genuine 'jumps to conclusions,'" McKay added. "Our results confirm that delusion-prone people are less likely to wait for the best moment before making a decision. This indicates that they would rush to make choices in their everyday lives, relating to anything from money or jobs to family and friends, which could lead to less successful outcomes for them."

Previous studies had only compared the decisions of delusion-prone and non-delusion-prone people to each other rather than to an objective measure of performance.

"Surprisingly, our study also found that even low delusion-prone people jumped to conclusions - so most people jump to conclusions, but delusion-prone people jump further," McKay added.

The findings were published in the journal Psychological Medicine.