Social Proof

Image of Spotify app with social proof

Social Proof Definition:

Social proof or social validation refers to a psychological instinct where people use the popularity of a behaviour, product, idea or social norm to guide their actions, especially when uncertainty exits (e.g. if purchasing a product for the first time).

Work by Mark Earls has shown that our ‘herd instinct’ drives much of our behaviour and many of our purchases are influenced by what we think other people are doing. Such behaviour reduces our anxiety about a decision because we assume that if other people are making the same choice they must know something we don’t.

In the test below for  we improved the social proof of the landing page by adding a selfie gallery of images sent in by recent winners. We also created a heading to communicate the winners theme.  The bullet point copy was included in one variant, but the winning experience had no bullet points. The winning variant achieved an uplift in  registration conversion of over 30%.

Image of innovation A/B test on


Spotify use social proof in their music app to show the popularity of playlists, artists, albums and individual songs. This helps to give people confidence to explore new artists or genre as they can instantly see which are the most popular.

Image of Spotify app with social proof

Social proof is also one of Robert Cialdini’s 6 principles of persuasion outlined in his book Influence. The online gambling company  tested displaying Facebook Likes on  their standard landing page along side the 5 other principles of persuasion from Robert Cialdini.

Image of Betfair landing page control variant
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The social proof variant below won the test with a 7% uplift in the click through rate to begin registration. None of the other principles of persuasion had a significant impact on the click through rate.

Image of Betfair landing page A/B test
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The E-commerce site cleverly uses social proof to reinforce the popularity of some items when visitors are viewing the product page. By this stage we know that users are showing some interest in the item. Messaging is briefly displayed showing the number of people currently viewing the product and how many units have been sold in the last 48 hours. This also creates a sense of scarcity which can nudge users towards purchasing an item.

Image of product page displaying social proof and scarcity indicators


Social proof can be a strong persuasive force in nudging prospects towards a purchase as it plays to our herd instinct. People use social proof as evidence of credibility and that other people trust a site. It is also an evolutionary approach to reducing the risk of making a poor decision as people know that unhappy customers make complaints that can damage a brand’s reputation. A brand with a strong reputation that has cost millions to establish won’t want to potentially damage this by selling faulty or low-quality products.



Conversion marketing – Glossary of Conversion Marketing.

Social influence & marketing – Are most purchase decisions the result of social influence?

Herd instinct – How do social networks influence human behaviour?

Social networks – What makes social networks tick?

Word-of-mouth marketing – 6 myths about word of mouth marketing.

Over 300 tools reviewed – Digital Marketing Toolbox.

A/B testing software – Which A/B testing tools should you choose?