Beliefs in conspiracy theories are seemingly hard to dispute through facts. Researchers have partly attributed this resistance to certain information processing styles that are associated with conspiracy beliefs. Previous research therein has extensively examined the role of object-level information processing, for instance, intuitive (vs. analytic) thinking and cognitive reflection. However, research has so far has not considered that conspiracy beliefs might also be related to different ways of metacognitive information processing. In two studies, one sample from Germany, one quota-based sample from the US (total N = 1,231), we show that a generic belief in conspiracy theories as well as the belief in specific conspiracy theories such as those surrounding vaccinations and QAnon (but less so conspiracy mentality) is related to lower metacognitive sensitivity – i.e., a lower ability to accurately evaluate one’s knowledge. Results hold when controlling for object-level knowledge, cognitive reflection, and intuitive thinking.

Social norms are powerful predictors of pro-environmental behavior. At the same time, conspiracy beliefs are prevalent that can reduce individuals’ efforts to act pro-environmentally and might impede the influence of social norms. Across three cross-sectional studies in three countries (Germany, UK, US; total N = 1,037), we investigated the interplay between different types of social norm perceptions and conspiracy beliefs in predicting everyday pro-environmental behavior. Against two out of three hypotheses, we found no evidence that conspiracy beliefs moderated the relationship between perceived social norms and self-reported pro-environmental behavior. Rather, perceiving higher pro-environmental social (especially subjective and injunctive) norms was associated with more frequent pro-environmental behavior – also among those with stronger conspiracy beliefs. Conspiracy beliefs (especially those related to climate change) were, in turn, related to less pro-environmental behavior. These findings shed light on the social factors that might (also) influence individuals believing in conspiracy theories and give reason for optimism regarding the possibility to overcome their climate inaction via normative influence.

Data for: Pummerer, L., Reinhardt, C., & Nielsen, M. (2025). Leaving the Catholic Church: Cross-Sectional and Longitudinal Predictors of Leaving Intentions. The International Journal for the Psychology of Religion, 1–18. https://doi.org/10.1080/10508619.2025.2553408

This study examines the relationship between conspiracy beliefs and perceived procedural justice regarding COVID-19 policies during the peak and decay of the pandemic (May/June 2022 – September 2023).

Data for: Winter, K., Pummerer, L., von Oertzen, T., Hornsey, M. J., & Sassenberg, K. (2025). Conspiracy belief and opposition to wind farms: A longitudinal study. Journal of Environmental Psychology, 104, 102620. https://doi.org/10.1016/j.jenvp.2025.102620

Believing in conspiracy theories is connected to support for non‐normative collective action. One explanation might be that this is due to both being non‐normative. Alternatively, it might be the case that non‐normative action appears justified based on what conspiracy theories alleging harm to a personally relevant group due to powerholders’ secret actions imply about social reality. To test this assumption, we focus on the belief in a norm‐consistent (i.e., popular and plausible) climate policy conspiracy theory alleging that powerful groups (i.e., politicians and the business sector) act without public oversight, leading to climate policies that suit their interests but are harmful to the public. Across three studies—one using a quota‐based German sample and two preregistered replications (Ntotal = 1257)—we investigate how the belief in such a theory relates to the endorsement of non‐normative collective action, and test whether this relationship also emerges for the belief in a norm‐inconsistent (i.e., implausible and unpopular) climate policy conspiracy theory suggesting a similar social reality (Study 3). Our data show that beliefs in both norm‐consistent and norm‐inconsistent climate policy conspiracy theories correlate positively with support for non‐normative collective action, while only the belief in a norm‐consistent climate policy conspiracy theory was related to normative collective action. In contrast, a stronger predisposition to believe in conspiracy theories (i.e., conspiracy mentality), albeit positively correlated with belief in a norm‐consistent climate policy conspiracy theory, was related to lower support for non‐normative collective action serving climate protection.

Data for: Winter, K., Hornsey, M.J., Pummerer, L. et al. Public agreement with misinformation about wind farms. Nat Commun 15, 8888 (2024). https://doi.org/10.1038/s41467-024-53278-2

Conspiracy beliefs (i.e., beliefs in specific conspiracy theories or the more general conspiracy mentality) are associated with a need for uniqueness and lower adherence to social norms. These findings suggest that conspiracy beliefs might be generally associated with less influence by majority opinions – absolutely and compared to minority opinions. In five experiments involving scenarios unrelated to conspiracy theories (overall N = 1669), participants were informed about the majority/minority opinion on a given issue (e.g., the building of a tunnel), afterwards indicating their evaluation or voting intentions regarding the issue. We then tested whether the influence of a majority/minority opinion on evaluation or voting intentions is moderated by conspiracy beliefs. Across studies, we find no significant moderation. A meta-analysis confirms no correlation between conspiracy beliefs and susceptibility to majority influence. Taken together, our studies provide no evidence for the assumption that those holding conspiracy beliefs reject majority opinions per se.

Dataset for: Winter, K., Pummerer, L., & Sassenberg, K. (2023). Change by (almost) all means: The role of conspiracy mentality in predicting support for social change among the political left and right. In European Journal of Social Psychology. Wiley. https://doi.org/10.1002/ejsp.2995

People believing in conspiracy theories question mainstream thoughts and behavior, but it is unknown whether it is also linked to lower adherence to the prosocial norms of the broader society. Furthermore, interventions targeting correlates of the belief in conspiracy theories so far are scarce. In four preregistered, mixed-design experiments (Ntotal = 1,659, Nobservations = 8,902), we tested whether believing in conspiracy theories is related to lower prosocial norm adherence and whether deliberation about the reason for the norms mitigates this relationship. Across four studies with the U.S. samples, we found that believing in conspiracy theories correlated negatively with prosocial norm adherence in the control condition, which was less pronounced after deliberation (effect size of interaction: d = 0.16). Whether the norm was related to the law or not did not moderate this effect. Results point toward possible ways of mitigating negative correlates and potentially also consequences of believing in conspiracy theories.