A convenient shortcut that users take to determine how 
to behave

What is social proof?

When people make decisions they are often influenced by the actions of others, particularly when they are uncertain or the situation is ambiguous.

The higher the number of people voicing the same (or similar) opinion, the more appropriate the action seems to the user.

Robert Cialdini coined the term 'Social Proof' to explain this principle in 1984.

How can brands use it?

Customer reviews on websites are the biggest use of this principle, with testimonials and ratings showing who else has bought the product, and how they found their experience.

Behaviour can also be influenced if people in your social media network are posting about watching a certain film, or using a specific product. Even if you haven't heard them before it's likely you'll consider watching the film or buying the product yourself.

ASOS use social proof to their advantage

ASOS use social proof in the form of customer reviews - users can rate the product out of 5 stars and ASOS also display the number of reviews. This increases trust in the brand and nudges users towards purchase.

ASOS don’t just leave it at reviews though and also make good use of other cognitive principles. They tackle potential objections from users by displaying detailed size and fit information (as well as other categories). They avoid information overload by clearly labeling the categories and making them expandable. Users have the choice to read more if they require the information. Social proof is also more effective if the people providing the proof appear to be like the user.

In comparison, Three don’t have any customer reviews

The Three product page information is all over the place with multiple CTAs making eye tracking across the page confusing – you don’t quite know where you should look first! (Btw That’s another cognitive principle for another article coming up soon!)

Similar principles to consider

The social proof principle is closely linked to the ‘bandwagon effect’ and ‘loss aversion’ principles - the more users see positive comments, the more they want to experience the product themselves, they feel FOMO (fear of missing out) which can be a powerful driver of behaviour.

‘Authority bias’ (also named by Cialdini) is when users attribute more importance to the opinion of an authority figure (review or recommendation from an expert, celebrity or influencer).

In The Style - an ecommerce retail brand - place a huge focus on this cognitive principle by showcasing the hottest influencer collections to inspire and convince users to buy. Awards and trust seals can also convince users that a brand is more trustworthy than a competitor.

Quick wins for you

• If you are a B2B business then case studies and client testimonials are vital to have on your website.
• For B2C brands try to enable reviews / user feedback on your website to share positive experiences of previous users.
• If you can share how many customers have bought products as well as the reviews this will increase the social proof impact.
• If this is going to take some development time then it may be easier to add static testimonials on your homepage or award badges and trust seals you may have received. Admiral do this brilliantly: