It's not that believers in conspiracy theories are massively overconfident; there is no data on that, because the studies didn't set out to quantify the degree of overconfidence, per Pennycook. Rather, "They're overconfident, and they massively overestimate how much people agree with them," he said.
Ars spoke with Pennycook to learn more.
Ars Technica: Why did you decide to investigate overconfidence as a contributing factor to believing conspiracies?
Gordon Pennycook: There's a popular sense that people believe conspiracies because they're dumb and don't understand anything, they don't care about the truth, and they're motivated by believing things that make them feel good. Then there's the academic side, where that idea molds into a set of theories about how needs and motivations drive belief in conspiracies. It's not someone falling down the rabbit hole and getting exposed to misinformation or conspiratorial narratives. They're strolling down: "I like it over here. This appeals to me and makes me feel good."
Believing things that no one else agrees with makes you feel unique. Then there's various things I think that are a little more legitimate: People join communities and there's this sense of belongingness. How that drives core beliefs is different. Someone may stop believing but hang around in the community because they don't want to lose their friends. Even with religion, people will go to church when they don't really believe. So we distinguish beliefs from practice.
What we observed is that they do tend to strongly believe these conspiracies despite the fact that there's counter evidence or a lot of people disagree. What would lead that to happen? It could be their needs and motivations, but it could also be that there's something about the way that they think where it just doesn't occur to them that they could be wrong about it. And that's where overconfidence comes in.
Ars Technica: What makes this particular trait such a powerful driving force?
Gordon Pennycook: Overconfidence is one of the most important core underlying components, because if you're overconfident, it stops you from really questioning whether the thing that you're seeing is right or wrong, and whether you might be wrong about it. You have an almost moral purity of complete confidence that the thing you believe is true. You cannot even imagine what it's like from somebody else's perspective. You couldn't imagine a world in which the things that you think are true could be false. Having overconfidence is that buffer that stops you from learning from other people. You end up not just going down the rabbit hole, you're doing laps down there.