On the multi-causal nature of jumping to conclusions in psychosis

Jumping to conclusions (JTC) is the most widely researched cognitive bias in schizophrenia. Notwithstanding meta-analyses demonstrating a higher level of JTC across the psychosis spectrum, important research questions remain unanswered. First, whether JTC is a primary process or in part an epiphenomenon reflecting contributions of other variables is still unresolved, which may explain why interventions targeting cognitive biases are effective on positive symptoms but less so on reducing JTC. Secondly, the beads task, the traditional procedure to capture JTC, is a complex procedure prone to misunderstanding and vulnerable to inattentive and careless responding. In this study, we tested a video assessment of the beads task aiming to reduce errors due to misunderstanding and to gain more insight into the processes contributing to JTC.

A sample of 801 participants from the general population was divided into various levels of paranoid ideation, based on cut-off criteria. The newly developed video JTC task, which is available at no cost at https://clinical-neuropsychology.de/jtc/, was presented online, as were the Revised Green et al. Paranoid Thoughts Scale (R-GPTS) and other psychological scales that served to separate individuals scoring high versus low on paranoia.

As hypothesized, participants scoring high on both the ideas of social reference and persecution subscales of the R-GPTS showed more JTC than those with lower scores. Yet, a large number of participants (24 %) made illogical responses or showed signs of careless performance. Important contributors to JTC were lack of motivation, skipping some of the instructions, and speeding through the trials. Yet, significant differences remained when these influences were accounted for with matched samples.

While the newly developed video task was able to confirm elevated JTC in individuals scoring higher on paranoid ideation, core problems seen in prior versions of the beads task remain. Researchers are advised to develop alternative tests, preferably ones that allow repeated measurement. Our results indicate that JTC is a multi-causal bias that is unlikely to be explained by a single cognitive or psychopathological process.