Social Proof

The concept is explained by Robert Cialdini, in his book ‘Influence Science and Practice’:

We view a behavior as correct in a given situation to the degree that we see others performing it. Whether the question is what to do with an empty popcorn box in a movie theater, how fast to drive on a certain stretch of highway, or how to eat chicken at a dinner party, the actions of those around us will be important guides in defining the answer.

Social proof is most influential under two conditions. The first is uncertainty. When people are unsure, when the situation is ambiguous, they are more likely to attend to the actions of others and to accept those actions as correct. The second condition under which social proof is most influential is similarity: People are more inclined to follow the lead of similar others.

Advertisers love to inform us when a product is the ‘fastest-growing’ or ‘largest- selling’ because they don’t have to convince us directly that the product is good; they need only say that many others think so, which seems proof enough.

The best illustration I know, however, comes from Singapore, where a few years ago, for no good reason, customers of a local bank began drawing out their money in a frenzy. The run on this respected bank remained a mystery until much later… an unexpected bus strike had created an abnormally large crowd waiting at the bus stop in front of the bank that day. Mistaking the gathering for a crush of customers poised to withdraw their funds from a failing bank, passersby panicked and got in line to withdraw their deposits, which led more passersby to do the same. Soon after opening its doors, the bank was forced to close to prevent a complete crash.