The Efficacy of Interventions in Reducing Belief in Conspiracy Theories: A Systematic Review

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Cian O’Mahony, Maryanne Brassil, Gillian Murphy Conor Linehan


Conspiracy beliefs have become a topic of increasing interest among behavioural researchers. While holding conspiracy beliefs has been associated with several detrimental social, personal, and health consequences, little research has been dedicated to systematically reviewing the methods that could reduce conspiracy beliefs. We conducted a systematic review to identify and assess interventions that have sought to counter conspiracy beliefs. Out of 25 studies (total N = 7179), we found that while the majority of interventions were ineffective in terms of changing conspiracy beliefs, several interventions were particularly effective. Interventions that fostered an analytical mindset or taught critical thinking skills were found to be the most effective in terms of changing conspiracy beliefs. Our findings are important as we develop future research to combat conspiracy beliefs.



Publication Date:



O’Mahony, Cian, et al. “The Efficacy of Interventions in Reducing Belief in Conspiracy Theories: A Systematic Review.” PLOS ONE, vol. 18, no. 4, Apr. 2023, p. e0280902. PLoS Journals, https://doi.org/10.1371/journal.pone.0280902.


Conspiracy Theories


The Project Gravity Team

Comment Date:



This article examines effectiveness of conspiracy thinking interventions. One effective intervention in conspiracy thinking occurs before participants were expose to conspiracy statements (inoculation interventions). Pre-emptively refuting inaccuracies of conspiracy theories was much more effective than traditional counterarguments that were made after participants encountered conspiracy theories. However, if participants were warned about inoculation interventions beforehand, the effects were negated. Priming interventions to instill critical thinking skill in their participants were moderately successful. Participants that were primed to feel more in control had lower conspiracy beliefs. The most effective intervention involved teaching students about differntiation between good scientific practice and pseudoscience.

The researchers summarized the practical implications of their findings as follows:

  1. Avoid appealing to emotions and affect: Interventions that manipulated the emotional state of participants, or appealed to feelings of empathy had small effects in terms of changing conspiracy beliefs.
  2. Counterarguments are not effective: Counterarguments against specific conspiracy beliefs that are given after participants have been exposed to a conspiracy theory tend not to be particularly effective.
  3. Prevention is the best cure: Interventions that provided counterarguments for conspiracy theories were most effective when the counterargument came before the participants were exposed to the particular conspiracy theories that the study focused on. The findings suggest it is more difficult to challenge conspiracy beliefs once participants have started to believe in them. If participants have been taught why certain conspiracy theories are implausible before they have been exposed to conspiratorial media they are much more resistant to conspiracy beliefs.
  4. An analytical mindset and critical thinking skills are the most effective means of challenging conspiracy beliefs: Participants who were primed to have an analytical mindset were less likely to have conspiracy beliefs than controls. Furthermore, when interventions moved beyond putting participants in an analytical mindset, and actually explicitly taught them how to evaluate conspiracy beliefs using specific critical thinking skills, they were much less likely to have conspiracy beliefs.