What Does Social Proof Have to do with Human Decision Making?

We all know that when we are put in a new social situation, the best thing to do is to take cues from those around us, especially those with more experience in the situation, in order to fit in. For example, when we start a new job we often look to others to gather social cues on how we are supposed to act, what we are supposed to do and even when we are supposed to laugh. This is nothing new in human behaviour, after all, we are all tribal beings.

Looking for social cues from our peers is part of a much larger condition of human behaviour. As tribal and herd animals, humans feel most comfortable when they are assured they are following the norms of their specific cultural group. In behavioural economics this is called social proof.

Social proof is the psychological occurrence where people assume the actions of others or the actions of the majority is the correct behaviour for a given situation.

Social proofing is a powerful tool for marketing and advertising that has been used for decades. Think of the old McDonald’s signs promoting the number of burgers sold. That is a prime example of Popularity Social Proof.


McDonald’s is not the only company doing this. In fact it was a popular marketing technique long before Behavioural Economics ever became mainstream. However now we have a name for it and a much deeper understanding of why humans care about social proof.

With the increasing amount of online marketing, advertising and purchasing, it’s no surprise that social proofing has exploded in the last decade. Here are a few popular ways of using social proof to impact consumer behaviour:

Expert or Celebrity Social Proof

An expert on a specific subject or a celebrity gives their stamp of approval to a product or service. This causes people to actually judge the product or service not on its own merits but on their impression of the expert or celebrity. For instance if you believe the expert to be stylish, cool and hip, you will consider the product they like as also being stylish, cool and hip.


Case in point: Air Jordan’s are still the best selling sneaker in Nike’s history.

 User Social Proof

User social proof occurs when a user openly approves a product or service. It is often found online in the form of customer testimonials, ratings, likes and reviews. Seeing other people believe in a product, talk about it and rate it causes people to feel confident in the product and often persuades them to buy it.

unbounce Unbounce, an online landing page builder, does a great job of using customer testimonials to assure customers of their excellent product.

Wisdom of the Crowds Social Proof

Wisdom of the Crowds Social Proof is when a product or service is so widely adopted or liked that the user has no need to question its validity or quality and easily buys into the idea. This often occurs when a certain threshold is achieved. For example it is easier to convince someone to watch a YouTube video with 1,000,000 views than if the video only had 100 views. The larger number of hits the first video has stands to validate the quality of video. It is also what helps videos go viral.


The Gangnam Style video got over 1 billion hits in 5 months.

Wisdom of your friends Social Proof

Wisdom of your friends Social Proof is when our peers or friends like or approve products or services. Since we both like our friends and consider them to be similar to us, we often find it easy to quickly like or adopt this product of service. From a simple recommendation of a product or service by a friend, to seeing a brand liked by a friend on Facebook, what our friends approve impacts our feeling about products and services.

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As you can see, social proof plays a huge role in marketing and advertising. But that’s not all there is to it. The above examples all fit into what is called positive social proof, where the desired behaviour is in line with what is shown. For instance a customer review says they love the product. This is the dominant way of using social proof.

However, with an even greater understanding of the dynamics of social proof it is also possible to use negative social proof. Negative social proof means using examples of behaviour which is not desired, in order to get the outcome that is desired.

This version of social proof is rarely used because it is easy to use it incorrectly. Here is an example of how negative social proof fails.

The Petrified Forest National Park in the USA noticed small pieces of their petrified forsest were being stolen by visitors. This was leading to the erosion of the National Park by visitors. In an attempt to stop people from stealing the petrified wood the park put up sign reading:

“Many past visitors have removed wood from the park, changing the natural state of the Petrified Forest”

This actually led to an increase in destroying trees since people thought it was ok to do since so many others had. They felt they were following the norm and therefore didn’t feel discouraged in stealing the petrified wood.

However, if used correctly, negative social proofing can be amazingly effective. Here is a great example:

The experts over at Draft FCB Institute of Decision Making used negative social proof in an ingenious way. While working to come up with a marketing campaign for Dead Space 2, a violent video game aimed at teenage and young adults guys, the Draft FCB teamed realized that what the users wanted the most was a game their mom’s would hate. Draft FCB then produced a commercial showing how disgusted mothers were by this game. This use of negative social proofing worked to re-enforce the branding of the video game and led to an increase in its sales.

So there you have it, proof that social proof is a great marketing and advertising tool. When understood properly it can be used to help shape decision-making moments for current and future customers.

2 thoughts on “What Does Social Proof Have to do with Human Decision Making?

  1. Pingback: The Goldilocks Effect | Keep Marketing Fun

  2. Pingback: Do More Choices Really Make Us Happier? Choice Paradox and Human Decision- Making. | Keep Marketing Fun

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