Why do people go along with a norm they privately doubt?

People often go along with a norm they privately doubt because they wrongly believe everyone else supports it. Psychologists call this pluralistic ignorance, or a collective illusion: people mistakenly think others mostly hold a different opinion from their own, so many go along with a view they don't hold. A minority view can be mistaken for the majority one, or a majority view for a fringe one. Fear of backlash, embarrassment or the wish to look good can keep each person quiet, and each silence makes the illusion look more real.

Researchers Prentice and Miller found a clear case on a college campus. Students rated their own comfort with campus drinking and estimated their peers' comfort. On average, students were less comfortable than they believed the average student was. Over a semester, men's private attitudes shifted toward that mistaken norm, a pattern consistent with cognitive dissonance; women's showed no comparable shift.

The idea is a century old. In 1924 the psychologist Floyd Allport noted that people conform to norms on a large scale without agreeing with them, and proposed that people rarely act on their convictions unless they think others share them. The term 'pluralistic ignorance' first appeared in a 1931 book he wrote with his student Daniel Katz.

The illusion has costs. It has been linked to groupthink, in which small, close-knit groups make poor decisions, and to the bystander effect, in which witnesses don't act because nobody else visibly does.