The link between incoherent beliefs and conspiracism

A new study published in PNAS Nexus reveals a connection between incoherent belief systems and conspiratorial thinking. Researchers Alessandro Miani and colleagues utilized a Bayesian framework to assess belief coherence, finding that people who hold multiple contradictory beliefs are more likely to endorse conspiracy theories. Contrary to previous research, this study employed a nuanced approach, interpreting agreement ratings as subjective probabilities within a Bayesian context.

When individuals assigned a high probability to two mutually exclusive claims, the probabilities often exceeded 100%, indicating incoherence. The study analyzed data from eight prior studies involving 8,590 participants, as well as new data collected from an online survey of 469 Americans. The findings supported the hypothesis that stronger conspiratorial beliefs are associated with a higher likelihood of incoherent belief systems.

In reanalyzed data, the probability of holding incoherent beliefs increased from 3% among the least conspiratorial believers to 91% among the most conspiratorial. Participants were presented with 16 fictitious scenarios, and those scoring higher on a conspiracy mentality questionnaire were more likely to believe both explanations for a girl's disappearance simultaneously, a clear sign of incoherent belief.

However, the link between incoherence and conspiracism did not apply to all types of explanations. When the explanations presented were mundane accidents, conspiratorial mindset did not predict incoherence. Conversely, when one explanation was the strict negation of the other, the probabilities still had to sum to 100% for incoherence to manifest.

The authors suggest that incoherence in conspiracism can be attributed to two factors: a general reduction in logical monitoring and a content-specific endorsement of counter-narrative stories driven by worldview beliefs.