Dec 17, 2021

Social proof optimizers

The optimizing conditions for social proof are uncertainty, the many, and similarity. Let’s dive into each.


In my last post, I discussed an example of social proof regarding a chain of restaurants in Beijing who discovered that “most popular” was the best label to use to describe a dish and increase its sales. Although the labeled popularity of an item elevated its choice by all sorts of diners, there was one kind of customer that was most likely to choose based on popularity—those who were infrequent and therefore, unfamiliar visitors.

Consider how another simple insight made one man a multimillionaire. In 1934, after acquiring several small grocery stores, Sylvan Goldman noticed his customers stopped buying when their handheld shopping baskets got too heavy. This inspired him to invent the shopping cart. The contraption was so unfamiliar-looking that, at first, none of Goldman’s customers used one—even after he built more-than-adequate supply, placed several in a prominent place in the store, and put up signs describing their use and benefits. Frustrated and about to give up, he tried one more idea to reduce his customers’ uncertainty, one based on social proof. He hired shoppers to wheel the carts through the store. His true customers began following suit after they saw others using it and his invention swept the nation.

This tendency for everyone to be looking to see what everyone else is doing in uncertain situations leads to another fascinating phenomenon known as pluralistic ignorance. This phenomenon helps explain a troubling occurrence: the failure of bystanders to aid victims in agonizing need of help. People will often not react in an emergency situation because it is unclear who should take charge and they all look at what everyone else is doing to figure it out. This is why it is best to single out a person in the crowd if you are ever in need of help to reduce the uncertainty.

The Many

Here’s an experiment to try that illustrates the power of the many. Stand on a busy sidewalk, pick an empty spot in the sky or on a tall building, and stare at it for a full minute. Very little will happen around you during that time. Most people will walk past without glancing up and virtually no one will stop to stare with you. Now, on the next day, go to the same place and bring along some friends to look upward too. Within sixty seconds, a crowd will have stopped to crane their necks skyward with the group.

Another example of the influence of the many is the use of laugh tracks in sitcoms. Many of the most popular TV shows today add artificial laughter to their content to make audiences perceive the content as being funnier than it is. 

The many is a contagious form of influence. In 1761, London experienced two moderate-sized earthquakes exactly a month apart. Convinced by this coincidence that a third, much larger quake would occur on the same date a month later, a soldier named Bell began spreading his prediction that the city would be destroyed on the fifth of April. At first, barely anyone paid attention to his claims. But those who did took precautions by moving their families out of the city. The sight of this small exodus stirred others to follow, which, in cascading waves over the next week, led to near panic and a large-scale evacuation. Great numbers of Londoners streamed into nearby villages, paying outrageous prices for any accommodations. After the designated day dawned and died without a tremor, people returned to the city furious at Bell for leading them astray. Although, it wasn’t the crackpot Bell who was to blame, but the Londoners themselves who validated his theory to each other.

If we see a lot of other people doing something, it doesn’t just mean it’s probably a good idea. It also means we could probably do it too. When it comes to convincing people to conserve energy, social proof-based messaging generates 3.5 times as much energy savings as any of the other messages. Utility-company officials don’t trust it because of an entrenched belief that the strongest motivator of human action is economic self-interest. Contrary to their beliefs, it seems that telling homeowners that by saving energy, they could save a lot of money, doesn’t mean they would be able to make it happen. However, when people learn that many others around them are conserving energy, there is little doubt of its feasibility. It comes to seem realistic and, therefore, actionable.


The principle of social proof operates most powerfully when we are observing the behavior of people just like us. This phenomenon is coined the term peer-suasion.

For this reason, we are seeing many more companies these days advertise average-person testimonials. They know that one successful way to sell a product to ordinary viewers is to demonstrate that other “ordinary” people like and use it. 

People will use the actions of others to decide how to behave, especially when they view those others as similar to themselves. Of interest to sales people is how sales improve dramatically when they use names/testimonials from female customers with female prospects, males with males, and couples with couples.

An analysis of factors that impact the market share of national brands revealed that passage of time had surprisingly little influence on brands’ performance, less than 5 percent over three years. Geography, on the other hand, made an enormous difference. The strongest influence on market share, 80 percent, was due to geographical region. People’s brand choices moved in line with the choices of those like them, around them. 

Marketing managers might want to consider decentralized strategies targeting separate regions to a greater extent than they currently do, as research indicates people are regionally similar on attitudes, values, and personality traits—probably due to contagion effects.