When does jumping-to-conclusions reach its peak? The interaction of vulnerability and situation-characteristics in...

Persons with delusions tend to display a jumping-to-conclusions (JTC) bias which is considered relevant to delusion formation. However, its contribution in real life social scenarios is unknown. This study investigates whether JTC increases when decisions have to be made in delusion-relevant situations and whether the increase is uniquely moderated by delusion-proneness.

JTC was assessed by a social reasoning paradigm in 92 healthy participants that were classified as high, medium or low in paranoid ideation and social anxiety. Decisions had to be made for emotionally salient scenarios without direct self-relevance, self-relevant scenarios and delusion-relevant scenarios, by successively drawing pieces of information.

All participants drew less information in the scenarios that were self-relevant and delusion-relevant compared to non-self-relevant scenarios. Participants with higher paranoid ideation generally drew less information than persons with medium or low levels of paranoid ideation. However, the hypothesized interaction of delusion-proneness and type of scenario was not significant. Social anxiety had no effect on draws to decision in any of the task types.

The description of social encounters in the task does still not capture the full perceptual experience in real life encounters.

The data support the assumption that the formation of persecutory delusions might arise as a function of a delusion-specific JTC-bias in combination with a normal and functional tendency to collect less information in self-relevant situations.