In the early 1950s, the psychologist Solomon Asch asked students at Swarthmore College to take what they thought was a vision test. They had to say which of three lines matched the length of another line. The answer was obvious. But the other people in the room were Asch’s assistants, and on some rounds they all gave the same wrong answer out loud.
About 75 percent of the real participants went along with the wrong answer at least once.