The world is seemingly awash with conspiracy theories – from well-trodden examples such as fake Moon landings, the 9/11 truth movement, and Holocaust denial, to relative newcomers including COVID as a bioweapon, QAnon, and the belief that the science of climate change has been invented or falsified. While there is a public perception that conspiracy theories are becoming more prevalent, recent evidence suggests that the rate of conspiracism is relatively stable over time (Uscinski et al., 2022). At any point in history, it seems that a certain proportion of people find themselves vulnerable to conspiracy beliefs, but what distinguishes those who do from those who don’t, and what are the causal factors?

 

In the current study, Liekefett et al. (2023) investigated the critical role of rumination – a perseverative and repetitive focus on negative content leading to emotional distress. In particular, the authors asked whether one component of rumination referred to as brooding (dwelling on one’s worries and distressing emotions) has a specific causal role in the formation of conspiracy beliefs. In a series of preliminary experiments, the authors first established a procedure for successfully inducing rumination, identifying various boundary conditions and requirements for a successful design. In the main study (N=1,638 to 2,007 depending on the analysis), they asked whether the induction of brooding causes a significant increase in conspiracy beliefs. Manipulation checks were also included to confirm intervention fidelity (independently of this hypothesis), and exploratory analyses tested the effect of various moderators, as well as the causal role of a complementary manipulation of reflection – a component of rumination in which attention is focused on the issue at hand rather than one’s emotions.

 

As expected by the authors' preliminary work, manipulation checks independently confirmed the effectiveness of the brooding intervention. In answer to the main research question, participants who brooded over the worries and negative emotions associated with an issue were more susceptible to conspiracy beliefs compared to a control group. However, while this effect of brooding was statistically significant, the confidence interval of the effect size estimate overlapped with the authors' proposed smallest effect size of interest (d = 0.20), suggesting that the practical value of the effect remains to be determined.

 

Overall the findings are consistent with a range of psychological theories suggesting that rumination induces negative affect and/or narrows attention to negative information, which in turn may make conspiracy theories seem more probable and render individuals more vulnerable to cognitive bias. The authors note the importance of future work to define the smallest effect of practical significance, analagous to the criteria used to determine the 'minimal clinically important difference’ in medical research.

 

The Stage 2 manuscript was evaluated over one round of in-depth review. Based on detailed responses to the reviewers' comments, the recommender judged that the manuscript met the Stage 2 criteria and awarded a positive recommendation.

 

URL to the preregistered Stage 1 protocol: https://osf.io/y82bs
 
Level of bias control achieved: Level 6. No part of the data or evidence that was used to answer the research question was generated until after IPA.
 
List of eligible PCI RR-friendly journals:
 

• Advances in Cognitive Psychology
• Collabra Psychology
• Experimental Psychology
• International Review of Social Psychology
• Journal of Cognition
• Peer Community Journal
• PeerJ
• Royal Society Open Science
• Studia Psychologica
• Swiss Psychology Open

 

References
 

1. Uscinski, J., Enders, A., Klofstad, C., Seelig, M., Drochon, H., Premaratne, K. & Murthi, M. (2022) Have beliefs in conspiracy theories increased over time? PLOS ONE 17: e0270429. https://doi.org/10.1371/journal.pone.0270429

2. Liekefett, L. Sebben, S. & Becker, J. C. (2023). The Effect of Brooding about Societal Problems on Conspiracy Beliefs: A Registered Report. Acceptance of Version 2 by Peer Community in Registered Reports. https://osf.io/3e8wc