Enlarge / A woman wearing a sweatshirt for the QAnon conspiracy theory on October 11, 2020 in Ronkonkoma, New York. (credit: Stephanie Keith | Getty Images)

Belief in conspiracy theories is rampant, particularly in the US, where some estimates suggest as much as 50 percent of the population believes in at least one outlandish claim. And those beliefs are notoriously difficult to debunk. Challenge a committed conspiracy theorist with facts and evidence, and they'll usually just double down—a phenomenon psychologists usually attribute to motivated reasoning, i.e., a biased way of processing information.

A new paper published in the journal Science is challenging that conventional wisdom, however. Experiments in which an AI chatbot engaged in conversations with people who believed at least one conspiracy theory showed that the interaction significantly reduced the strength of those beliefs, even two months later. The secret to its success: the chatbot, with its access to vast amounts of information across an enormous range of topics, could precisely tailor its counterarguments to each individual.

"These are some of the most fascinating results I've ever seen," co-author Gordon Pennycook, a psychologist at Cornell University, said during a media briefing. "The work overturns a lot of how we thought about conspiracies, that they're the result of various psychological motives and needs. [Participants] were remarkably responsive to evidence. There's been a lot of ink spilled about being in a post-truth world. It's really validating to know that evidence does matter. We can act in a more adaptive way using this new technology to get good evidence in front of people that is specifically relevant to what they think, so it's a much more powerful approach."