In this video, Tim Harford tells the story of psychologist Leon Festinger’s infiltration of a cult led by Dorothy Martin in 1954. Festinger studied the cult members’ reaction to Martin’s false prophecy that the world would be destroyed the following day. Martin’s followers believed that aliens would arrive at midnight to collect true believers and take them to the planet Clarion, but when the aliens didn’t arrive the cultists could not accept their mistake. On the contrary, as Festinger pre...