Researchers have long debated why people believe in conspiracy theories—alternative explanations for events that often challenge the mainstream narrative. These beliefs can shape public opinion on issues ranging from politics to public health, such as vaccine hesitancy and pandemic precautions. A recent study published in Politics and the Life Sciences sought to explore whether stress—a common psychological and physiological response—could heighten an individual’s tendency to believe in conspiracy theories. The study found that while the stress procedure caused significant increases in cortisol levels (a hormone linked to stress), it did not make participants more likely to endorse conspiracy theories or interpret new information in conspiratorial terms.
The idea that stress might influence conspiracy thinking stems from earlier research suggesting that conspiracy beliefs often arise during crises or periods of uncertainty. Stressful situations might encourage people to search for meaning or feel a sense of control, which conspiracy theories could seem to provide. Moreover, psychological studies have linked perceived stress levels to a greater likelihood of endorsing conspiracy theories.
However, the exact mechanisms behind this relationship remain unclear. Could the biological effects of stress, such as the release of cortisol, play a role? The researchers behind this study aimed to address this question by isolating the physiological aspects of stress and testing their effects on conspiracy beliefs in a controlled experimental setting.
“Biological stress primes the body for action and can be measured physiologically, while subjective stress reflects our internal sense of unease,” said study author Vojtěch Pišl of the Department of Psychiatry at Charles University.
“Previous studies show that individuals who report feeling stressed are more likely to endorse conspiracy theories. This could stem from biological stress, which accelerates cognitive processing but increases the number of cognitive errors, or from social factors, where dissatisfaction with society leads people to report stress and endorse conspiracy theories as a form of protest. Our experiment aimed to confirmed the role of the biological effects. At the same time, we wanted to show that conspiracy research may benefit from physiological measurements.
To investigate the relationship between stress and conspiracy thinking, researchers used the Maastricht Acute Stress Test (MAST), a standardized procedure designed to induce acute stress. The study involved 143 medical students aged 20 to 25. Participants were randomly assigned to either an experimental group, which underwent the stress-inducing version of the MAST, or a control group, which experienced a non-stressful variant of the procedure.
The experimental stress procedure included both physical and social stressors. For example, participants submerged their hands in ice-cold water and were required to solve challenging arithmetic tasks under time pressure while receiving critical feedback. In contrast, the control group performed similar tasks but in less stressful conditions, such as using lukewarm water and receiving polite encouragement instead of criticism.
To measure the participants’ stress response, researchers collected salivary samples at multiple points during the study to assess cortisol levels. These samples were taken before, during, and after the MAST procedure. The participants also completed two types of surveys: one gauging their agreement with existing conspiracy theories (e.g., theories related to geopolitical events) and another measuring their likelihood of adopting conspiratorial interpretations of fictional scenarios.
To ensure accuracy, participants were required to follow specific guidelines before the study, such as avoiding caffeine and alcohol, refraining from smoking, and maintaining a consistent eating schedule. Additionally, the study excluded participants who did not exhibit sufficient cortisol responses to the stress procedure or whose survey responses showed inconsistencies.
The results confirmed that the stress procedure effectively increased cortisol levels in the experimental group, validating the biological impact of the stress induction. However, when comparing the two groups, researchers found no significant differences in their responses to either the survey of existing conspiracy theories or the fictional scenarios. In other words, the acute stress experienced by participants did not increase their likelihood of endorsing conspiracy theories or interpreting novel information in a conspiratorial way.
Exploratory analyses suggested that any potential effects of stress on conspiracy thinking were small or absent. The findings imply that while stress might influence cognition in other ways, it does not appear to play a significant role in shaping conspiracy beliefs—at least not in the short term or under controlled experimental conditions.
“Conspiracy theories might be more deeply tied to social processes and social identity than we often realize,” Pišl told PsyPost. “Moreover, many negative effects of stress could be more closely linked to our subjective interpretation of reality—such as thinking ‘everything is wrong, I feel terrible’—rather than the objective events themselves. Our experiment is just one small piece of the puzzle, but it aligns with a broader body of research showing that our perception that the world is a good place and that we are strong and resilient may be often more relevant that what is actually happening.”
While the study offers valuable insights, it is not without limitations. One key limitation is the sample itself. The participants were medical students—a group likely to possess higher-than-average analytical thinking skills and greater exposure to scientific reasoning. These characteristics might make them less susceptible to conspiracy thinking than the general population, potentially limiting the generalizability of the findings.
Additionally, the study focused on acute stress, measuring its effects within a narrow time frame (roughly 30 minutes after stress induction). Stress responses can vary over time, and it is possible that the effects on conspiracy thinking might emerge in different phases of the stress response, such as in the immediate aftermath or during prolonged stress. Future research could explore how stress affects conspiracy beliefs over longer periods or in real-world contexts.
“Our results were negative; we did not confirm a link between biological stress and the endorsement of conspiracy theories,” Pišl said. “However, this doesn’t imply that the link is nonexistent. Instead, it suggests that the connection is likely weaker than the link between subjectively perceived stress and conspiracy beliefs.”
Understanding the factors that drive conspiracy beliefs remains an important area of inquiry, especially in today’s polarized and misinformation-rich world.
“We plan to continue with EEG studies to explore the brain processes that may underlie the decision to endorse conspiracy theories,” Pišl said. “The study was supported by the American Association for Politics and Life Sciences, along with several Czech and European institutions. I am deeply grateful for this support, which provided not only the necessary funding but also the motivation to pursue these endeavors.”
The study, “The effect of acute stress response on conspiracy theory beliefs,” was authored by Vojtech Pisl, Turkay Nefes, Benjamin Simsa, Daniela Kestlerova, Pavel Kubíček, Vojtech Linka, Tatana Martynova, Rachel Sajdlova, David Sejrek, and Jan Vevera.
