"This relationship with overconfidence was robust in controlling for analytic thinking, the need for uniqueness, & narcissism, & it was strongest for the most fringe conspiracies. We also found that conspiracy believers—particularly overconfident ones—massively overestimated (>4×) how much others agree with them... conspiratorial claims were believed by a majority of participants only 12% of the time, believers thought themselves to be in the majority 93% of the time"

https://journals.sagepub.com/doi/10.1177/01461672251338358