What goes behind the radicalisation of men and women on YouTube

Caleb Cain was a college dropout looking for direction. He turned to YouTube.

Soon, he was pulled into a far-right universe, watching thousands of videos filled with conspiracy theories, misogyny and racism. “I was brainwashed.”

Caleb Cain pulled a Glock pistol from his waistband, took out the magazine and casually tossed both onto the kitchen counter. “I bought it the day after I got death threats,” he said.

The threats, Mr. Cain explained, came from right-wing trolls in response to a video he had posted on YouTube a few days earlier. In the video, he told the story of how, as a liberal college dropout struggling to find his place in the world, he had gotten sucked into a vortex of far-right politics on YouTube.