Conspiracy theorists and religious people are more likely to commit a ‘conjunction fallacy’ in contexts related to their worldviews
by Beth Ellwood
August 11, 2021
in Cognitive Science, Conspiracy Theories


A study published in Applied Cognitive Psychology sheds light on how a person’s worldview can lead them to jump to erroneous conclusions in domains that correspond to these views. The researchers found that greater conspiracy belief was associated with increased susceptibility to making logical errors in the context of coronavirus conspiracies, and greater religiosity was tied to increased susceptibility to logical errors in the context of miraculous healings.

The study, led by Albert Wabnegger, specifically focused on the conjunction fallacy, a logical fallacy that presumes that a combination of events is more probable than a single event. Conjunction fallacies were first described by Tversky and Kahneman in 1982, following a study that began with participants reading a description of a woman named Linda who was passionate about social justice. Most participants evaluated the statement “Linda is a bank teller and is active in the feminist movement” as more probable than “Linda is a bank teller” — without knowing Linda’s job title or position on feminist issues. According to probability theory, two events (being a bank teller + being active in the feminist movement) cannot be more probable than a single event (being a bank teller).

Previous research has shown that greater conspiracy belief is linked to an increased likelihood of making conjunction errors. In a new study, Wabnegger and his colleagues wanted to extend these findings by exploring whether specific beliefs would be associated with susceptibility to conjunction fallacies in specific domains. For example, would people who believe in conspiracy theories be more prone to conjunction errors in contexts related to conspiracy theories?

A total of 500 participants completed measures of general belief in conspiracy theories and general religiosity. They then went through an exercise to assess their susceptibility to conjunction errors.

The participants read 18 scenarios and were asked to choose which of two statements was most likely. One statement included a single event (e.g., “The Bill Gates Foundation strives for a high vaccination rate.”) and a second statement included two events (e.g., “The Bill Gates Foundation strives for a high vaccination rate and thus wants to increase its wealth.”). The scenarios were related to one of three domains: COVID-19 conspiracies, miraculous healings, or everyday situations (control condition). All participants read all 18 scenarios, and each participant was scored based on how many times they committed a conjunction error.

Nearly three-quarters (74%) of the respondents made at least one conjunction error when responding to the scenarios. Moreover, susceptibility to making a conjunction error in a particular domain was linked to specific beliefs. For example, those with greater conspiracy belief were more likely to make logical errors in response to the COVID-19 conspiracy scenarios but not in response to the other scenarios. Those with greater religiosity were more likely to make logical errors in response to the miraculous healing scenarios but not the other scenarios. When it came to the control condition, neither conspiracy belief nor religiosity predicted the likelihood of committing a logical error.

Wabnegger and colleagues theorize that when people with a particular world view — such as a conspiracy mindset — are met with information that corresponds to this view, they are quicker to draw conclusions about the information but more likely to make errors. Favoring a conclusion that fits their preconceptions, they ignore basic probability laws or the need for additional evidence.

Furthermore, studies suggest that religious people and conspiracy supporters tend to have a lower tolerance for randomness and a greater tendency to detect meaningful patterns out of random stimuli. Perceiving two distinct occurrences as more probable than one alone may reflect these individuals’ readiness to discern patterns out of randomness as a way of coping with uncertainty.

The authors note that their study cannot inform whether proneness to conjunction errors is a cause of religiosity/conspiracy belief, or whether it might be a response to such belief. They say a follow-up study with a longitudinal design would offer further insight.

The study, “The association between the belief in coronavirus conspiracy theories, miracles, and the susceptibility to conjunction fallacy”, was authored by Albert Wabnegger, Andreas Gremsl, and Anne Schienle.