CODEXCard 11 of 12 · 12 Mental Models
Social proof
Crowds are usually right. Until they're not.
Social proof is the tendency to look at what other people do and take it as a guide to what we should do. The term was popularised by psychologist Robert Cialdini, and Munger included a social-proof tendency in his 1995 talk on human misjudgment. Following others saves effort, and in familiar situations it usually leads somewhere sensible.
The tendency is strong because, for most of history, copying the group was a reasonable bet. If everyone avoids a certain plant or path, there is probably a reason. Munger's point was that the same instinct can misfire badly. When people are uncertain, rushed or under pressure, they copy one another rather than the facts, and a crowd can move confidently in the wrong direction.
The opposite trap is making contrarianism a personality. Disagreeing with the crowd is not a strategy in itself, and most disagreements turn out to be wrong. Going against consensus pays only when you have done the work to understand why the crowd is mistaken in this case. Without that, you are simply betting against the odds.
Social proof is a common ingredient in lollapalooza effects, where it stacks with incentives and urgency. It also helps explain manufactured consensus online, where the look of a crowd can be created artificially.
Example
You are travelling and see two restaurants side by side, one full and one empty. Choosing the busy one is usually sensible. But if you learn that a tour bus just dropped its whole group at the busy door, the crowd tells you about the bus schedule, not the food.
Try it this week
The next time you follow a popular choice, ask what the people around you actually know that you do not.
From 12 Mental Models (Charles T. Munger · 1995).
