Pluralistic Ignorance

What it is

Katz and Allport reported the pattern in Students' Attitudes, their Syracuse University reaction study of 1931. Allport is conventionally credited with the term and Katz is the first author of the report, so both names belong on it.

The mechanism is an asymmetry of access. You can see what people do and you cannot see what they think, so you infer their beliefs from their behaviour, and so does everyone else, and everyone is inferring from the same visible surface. Each person concludes they are the exception.

Robin Hanson and Kevin Simler supply the sharper analytic vocabulary for why the misperception is stable, borrowing common knowledge from Michael Chwe's Rational Ritual. Secrecy has two dimensions rather than one: how widely a thing is known, and how openly it is known. A thing can be known by everyone and still not be common knowledge, and the difference is whether each person knows that the others know. Their worked example is The Emperor's New Clothes, where the child's shout adds no information and instead converts private knowledge into common knowledge, at which point the silence collapses. Note that the story is a closer fit to the common-knowledge problem than to pluralistic ignorance strictly defined, since in the story the private beliefs are read correctly and left unsaid, whereas in pluralistic ignorance they are misread. Timur Kuran's preference falsification is the political-scale version of the same thing.

In effect

The campus-drinking case is the best-known application. Deborah Prentice and Dale Miller showed in the Journal of Personality and Social Psychology in 1993 that students believed their peers were more comfortable with campus drinking than they actually were. Misperceived drinking norms have been widely replicated since, including by Brian Borsari and Kate Carey in 2003.

The intervention story usually attached to it does not stand up as well. Jonah Berger reports in Contagious that Koreen Johannessen found University of Arizona students were mostly uncomfortable with campus binge drinking, and that advertising the true norm cut heavy drinking substantially where years of frightening them had done nothing. That figure comes from Berger's interview with her rather than from a published evaluation, and it has not been traced to a primary source, so this publication does not cite it. More importantly, a Cochrane review led by David Foxcroft in 2015, covering seventy studies, found no substantive benefit from social-norms interventions and no effect from marketing campaigns.

The workplace form of the same silence is psychological safety, and the reading that matters for organisations is that the norm survives because belief stays private. It dies when belief becomes public, which is a fact about disclosure rather than about persuasion.

What it does not say

It does not say that correcting the perception changes the behaviour. The misperception is robust; the intervention built on it has been tested at scale and has not delivered.

It does not say that everyone secretly disagrees with every norm. It describes a specific condition in which private rejection is widespread and invisible, which has to be demonstrated rather than assumed.

It is not the same as a common-knowledge failure. Where private beliefs are read correctly and simply left unsaid, the problem is that nobody knows the others know, which is a different repair.

It does not supply the Arizona figure as data. That number comes from an interview, not an evaluation, and is not carried here.

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