In brief: Most of those questioned said they stumbled upon the Flat Earth idea while watching conspiracy videos on topics ranging from 9/11 and the Sandy Hook school shooting to whether or not the moon landing was fake.

YouTube is being blamed for the sharp rise in the number of people who believe the Earth is flat.

Researchers from Texas Tech University attended the world’s largest gathering of Flat Earthers in 2017 and 2018. During the conferences, interviews were conducted with 30 attendees that revealed a pattern regarding their beliefs.

Of the 30 people interviewed, all but one said they had not considered the Earth to be flat two years ago but changed their views after watching videos supporting the idea on YouTube. The other person learned of the idea after his daughter and son-in-law – who had seen Flat Earth videos on YouTube – told him about it.

Lead researcher Asheley Landrum presented her findings at the American Association for the Advancement of Science’s annual meeting in Washington, D.C., this past weekend. Landrum said YouTube’s algorithms make it easy to “end up going down the rabbit hole by presenting information to people who are going to be more susceptible to it.”

YouTube in January said it was taking steps to reduce recommendations of “borderline” content that comes close to – but doesn’t quite violate – its community guidelines, like videos claiming the Earth is flat and those promoting miracle cures for grave illnesses.

Lead image courtesy Amanda Carden via Shutterstock