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Social Proof Marketing: 4 Factors That Enhance Group Persuasion
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Have you ever wondered why TV shows use canned laughter, or why bartenders put money in their own tips jars? Have you ever thought about how celebrities shape fashion trends, or why your opinions seem to match those of your peers? The answers can tell you a lot about Social proof marketing.

Here, we explore the scientific basis of Social Proof and identify 4 key factors that make it such a powerful marketing tool:

  1. Uncertainty
  2. Similarity
  3. Attraction
  4. Desire

Social Proof Marketing

Social proof is a phenomenon that shapes our behaviour through imitation and consensus. It is one of the strongest tools of influence and persuasion. There are certain circumstances under which social proof works better than others, such as when the right course of action is uncertain or when we perceive ourselves to be similar to those already engaging in the behaviour.

This article will explain why social proof is such an effective persuasion tactic and how it can be used in marketing. 

As Cavett Robert, an expert in sales and marketing, famously stated:

95 % of people are imitators and only 5% initiators…people are persuaded more by the actions of others than by any proof we can offer.” (Human Engineering and Motivation, New York 1969)

Most people are instinctively sceptical of this statement. Surely, people have their personal preferences? However, two recent studies suggest that our preferences are less personal than they seem…

Musical Taste and Social Proof – The Salganik Experiment

In 2008, Mathew Salganik conducted an experiment on personal preference.

He created an artificial music market and manipulated the way songs were rated so that some, which had previously received a low rating, were made to appear as the “most popular.”

Remarkably, he found that the songs with artificially enhanced popularity became his participants’ favourites! The study illustrated just how powerful social proof can be.

Hotel Towels and Social Proof – Goldstein and Cialdini

In an another experiment, the “fathers of persuasion” Robert Cialdini and Noah Goldstein studied the best way to encourage environmentally friendly behaviour in hotels. Their task was to persuade guests to reuse their towels.

Cialdini and Goldstein used two different signs in the hotel bathrooms. In one condition (“A”) they provided guests with a standard environmental message (“Help save the environment…”) In the other condition (“B”) the message read: “Join your fellow guests in helping to save the environment.”

Message “B” increased the percentage of towels reused by over 25%

As with any marketing tool, there are certain conditions in which Social Proof is more effective. In the rest of this article, we look at four key factors, and consider why the effect is such a powerful marketing tool.

When it comes to social proof, the two biggest factors are uncertainty and similarity. However, studies have also shown that attractiveness and desirability play a role.

First, let’s take a look at uncertainty. Ambiguity and doubt have been shown to enhance the effect of social proof.

Modern life presents an overwhelming amount of choice. Not only do we have to decide between toast or cereals for breakfast, we now have to choose between hundreds of different brands for each.

Decision-making can be exhausting, and this  increases that likelihood that we will look to our peers for recommendations and advice.

…how is uncertainty related to marketing?

With the emergence of large e-commerce platforms such as Amazon and Ebay, which offer an unprecedented number of options for any given item, Social Proof is a way of simplifying our choices.

A recent investigation explored the most significant influence on consumer choices for sites such as It found that the most influential factor across all case studies was Customer Reviews. Subjects were particularly responsive to reviews written by their friends.

Have you ever wondered why you see these notifications on

There are now a number of apps that allow E-commerce sites to display Social Proof notifications. In a previous article, we examined the 3 Best Social Proof Apps available in Shopify, including our own FREE app Nudgify.

The next condition which intensifies the effect of social proof is similarity. We are more likely to copy the behaviour of those who are similar to us.

The characteristics that affect us most significantly are age and gender.

In 1984, the behavioural specialist David Murray conducted a study on the best way to stop adolescents from smoking. He compared four persuasive strategies and their effects on adolescent behaviour. The study found that the teenage subjects responded far more readily to advice and information from their same-age peers.

…what does this have to do with marketing?

Appealing to our social instincts is no secret to marketers. Just take a look at the following advertisement:

Social Proof and Yogurt for Men


Marketing campaigns across a number of industries use gender or age groups to target their products.

The third factor that significantly enhances the impact of social proof is attractiveness.

The principle of attractiveness is the simple rule that we are more likely to listen to and comply with people who we find attractive compared to those we do not. In 1979, Shelly Chaiken conducted an experiment in which her students were approached by one of two people. The first was “attractive,” and the other “unattractive.”

The responses to these people showed that subjects were significantly more likely to be persuaded by prompts from the attractive people. This was true not only for their verbal responses, but also for their behaviours.

…what does this mean for marketing?

In Cognitive Psychology, Association is the linking of two separate objects or concepts. Some researchers, for example Albert and Bernice Lott, have found that qualities such as attractiveness and like-ability are transferable.

In other words, positive feelings or experiences can be transferred to associated objects or ideas. This is one reason why “attractive” people and glamorous settings are used in advertisements. Creating a positive feeling in viewers allows associations to form between these feelings and the products on display.

Social Proof and tastethefeelings


Social Proof and perfume ad


The last condition that affects our likelihood to engage in a behaviour is its perceived “desirability.” From a very young age we are taught to moderate our behaviour according to the norms and standards of those around us. These ideas are extremely powerful and very difficult to change. However, when they do change, the effects can be dramatic.

There is no better example for this than the 1920s PR campaign in which Ms. Bertha Hunt and Edward Bernays (the “father” of modern public relations) reinvented the cigarette.

On 31st of March 1929, a young woman named Bertha Hunt stepped out onto Fifth Avenue in New York City and lit up a Lucky Strike cigarette. It was a daring act; at that time, women who were seen smoking in public were heavily stigmatised. 

Not only did Bertha Hunt smoke openly, but she and a group of her friends refused to extinguish their cigarettes when asked to do so. The incident was reported in the New York Times, where it was read with interest by the new PR consultant for the American Tobacco Company: Edward Bernays.

Bernays had been tasked with convincing women that smoking cigarettes was glamorous and turning it into an acceptable behaviour. But how could he do this? It seemed impossible to battle the years of heavy stigma. 

The answer was Social Proof.

During the Easter Sunday Parade of 1929, Bernays hired women to march along with the other displays, smoking their cigarettes. The stunt was accompanied by a slogan; cigarettes were not vulgar or masculine, they were now “Torches of Freedom.” By 1935, six years after the Bernays campaign, the percentage of cigarettes purchased by women in America had more than doubled.

….how is this relevant to marketing?

One of the biggest secrets in marketing is that individual preferences are almost impossible to change. Instead, marketers focus on convincing people that their product is popular. To strengthen this approach, they will suggest that their product is popular with people that their target market find attractive, relatable and recognisable. However, one of the most enduring forms of persuasion is simply to make a product or an idea Socially Desirable.

Social proof is the reason why shows use a laughter track, and why respondents consider such shows funnier than those without one.

Bartenders and buskers have learned to work with the principle of Social Proof. Many admit to “salting” their own tip jars at the beginning of an evening to encourage generous tipping.

Although the principle of social proof is not a new phenomenon, its influence over our lives is increasing. As “smart” technologies, media saturation and Machine Learning develop together, the effect of consensus and imitation is likely to grow.

To read more about Social Proof, explore our library of related articles.

If you have a Shopify page and would like to use Social Proof Marketing to improve your conversion rate, find out all about our Social Proof Marketing App Nudgify.

Stephen Courtney

by Stephen Courtney

Stephen is a Copywriter and Digital Marketing enthusiast, working with Convertize. He began his career doing academic research on technological systems and now communicates insights and market research to professionals.