Reasoning, delusion proneness and stress: an experimental investigation

Previous studies have been inconsistent in demonstrating a relationship between delusion proneness and induced stress on reasoning biases. The present study was an experimental investigation of the role of stress in the form of feeling rushed, which has previously been shown to be related to the jumping-to-conclusions reasoning bias for delusion-prone individuals, on the reasoning of delusion-prone individuals. University students (n = 133) completed a measure of delusion proneness and were randomly assigned to either receive or not receive a stress induction in the form of a speeded subtraction task. All participants engaged in four trials of a probabilistic reasoning task. Delusion-prone and not delusion-prone participants performed similarly when there was no stress induction, but delusion-prone individuals demonstrated reasoning biases relative to not delusion-prone individuals when stress was induced. The reasoning of delusion-prone individuals may be particularly vulnerable when they feel rushed and in stressful conditions.