Why do people buy what they buy?

Businesses and psychologists have been trying to answer this question for years.

Turns out, one big driver for purchasing decisions is social proof. Social proof serves as validation of a product’s quality or value for money. If many people like a product, your customers will assume that it must be good.

Savvy e-commerce store owners can increase conversion rates dramatically by leveraging social proof.

What is social proof and how can you use it effectively?

According to Robert Cialdini, psychologist and bestselling author of Influence: The Psychology of Persuasion, social proof is one of the six pillars of persuasion.

He says: “When we are uncertain, we are willing to place an enormous amount of trust in the collective knowledge of the crowd.”

This is a roundabout way of saying that people tend to follow what others are already doing.

According to the Theory of Diffusion of Innovations, social proof is critical for spreading an idea or trend. Barring a small minority (innovators and early adopters), the vast majority of people require social proof before they will adopt a trend or buy a product.

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For e-commerce stores, this means people are more likely to buy your products if you can show that the products are already popular.

Let’s look at some science-backed strategies for showing social proof.

Leverage the wisdom of crowds

We implicitly trust an opinion when it seems to come from a large group of people, as opposed to an individual.

As one Duke University paper stated: "A person may go along with beliefs expressed by most of the other people around him because he realizes that opinions shared by many are often more likely to be correct than the opinions held by a single individual.”

This helps explain why McDonald’s advertises the number of burgers it has sold:

Here’s how you can use this wisdom of crowds in your e-commerce store:

1. Use your social following

Showing off how actual customers use and enjoy your products can push would-be buyers to press the "buy" button.

For example, take a look at how ThinkGeek.com shares its customer photos on its home page:

ThinkGeek encourages customers to share their product pictures with the #geekfamous hashtag, curating the best of the lot on its homepage, which benefits ThinkGeek in two ways:

• It shows what every product looks like in-use.
• It proves that ThinkGeek’s products are already popular with a lot of people.

You can do something similar for your store:

• Start a contest on social media with a branded hashtag.
• Ask customers to share images of themselves using your products, making certain to include your hashtag.
• Embed these images on your site and each product page.

2. Use your client base

A well established client base can be a goldmine in driving additional business.

Why? These well-known clients will lend credibility to your business.

Voices.com increased their conversion rate by 400% by displaying the logos of their clients on their site:

Invesp increased conversions by 190% by listing clients’ names and logos in several locations on their website:

There are several ways you, too, can do this on your own site:

1. Display the number of clients you have.
2. Display big name clients.
3. Display the logos of your clients.
4. Display the number of projects your company has successfully completed.

3. Encourage product reviews

Onlineeviews are crucial for e-commerce success. The more positive reviews a product has, the more people are likely to purchase the product.

The data backs this up:

• 88% of customers consult reviews before making a purchasing decision.
• If a product has 20+ reviews (positive or negative), it will have a 83% higher chance of selling than one without any reviews.
• A one-star improvement in Yelp rating increases revenue by 5 to 9%.

This is why Amazon aggressively promotes its user reviews on every product page:

Follow these steps to get more reviews for your products:

• Send customers a follow-up email for a review a week after every purchase.
• Offer incentives for writing reviews (this can be a discount, a giveaway or a sweepstake.)
• Emphasize reviews on your site. If you have a lot of reviewers, you can even run a ‘Top Reviewers’ leaderboard like Amazon.

Tap into your customers’ fear of missing out

Fear of missing out, or FoMO, is a prominent phenomenon where people are driven to act on an impulse simply because they are afraid they won’t get the same opportunity again.

FoMO manifests itself particularly strongly in social trends. If you can convince others that they won’t be able to participate in a hot new trend, or miss out on a fast-selling product, you’ll increase conversion rates.

Retailers use this tactic when they advertise that they have limited stocks of a product:

But how can you implement FoMO on your own e-commerce site?

Here are two tactics:

1. Limit quantity of products sold

One effective way to tap into your customers' fear of missing out is to limit the number of available products on your site. This creates a scarcity incentive. These incentives are emotional factors that encourage visitors to act right away. You can do this by showing customers that certain sizes or variants of a product have already sold out. For example, Old Navy visually tells you when a size is out of stock:

Another method is to tell people how many items you currently have in stock. Amazon store does this by showing a warning message to customers when they have just 1–3 products left in stock.

Be careful not to overuse this tactic, though. If you show every product as going out of stock, you’ll probably destroy your customers’ trust.

2. Limit time-to-buy

Another way to tap into FoMO is to only offer products for a limited amount of time. This creates an urgency incentive. Similar to scarcity incentives, urgency incentives create an emotional force that encourage visitors to act right away.

Groupon built a billion-dollar company by offering each deal only for a short amount of time.

The company also shows the number of people who’ve bought the deal as additional social proof.

You can do the same by offering special promos, discounts, or special editions for only a few days/hours. You can also try offering free shipping only for a limited period of time (say, during the holidays).

Take advantage of the halo effect

Here's a paradox: In blind taste tests, most prefer Pepsi over Coke.

Yet, Pepsi trails far behind Coke in market share: It holds just 8.9% of the carbonated beverage market. (Coke owns 17%.)

This paradox can be best explained by the halo effect, which refers to a confirmation bias where we perceive people, products, or brands to be better than they actually are due to our pre-existing perceptions and biases.

This effect is especially pertinent for e-commerce stores, since it can lead to an immediate bump in conversions. Proving that your products are popular with celebrities and influencers, or that your brand is ‘superior’ (think Apple vs. Microsoft) can imbue your store with a positive halo.

Let’s take a look at a few tactics to leverage this form of social proof:

1. Improve your site design

Believe it or not, a well-designed, user-friendly website does more than simply make your brand look good: It improves your conversion rates.

According to research by Nielsen, strong design creates a halo effect on a website and its products. This leads to better conversion rates and happier customers.

2. Use testimonials and endorsements

Has an influencer or internet celebrity ever said anything good about your products?

If yes, make sure to plaster these comments all over your website.

Take a look at this ‘Praise’ page for blogger Marie Forleo. While she shares a lot of testimonials, she makes sure to highlight comments from major influencers like Richard Branson:

An easy way to source reviews and testimonials is to contact prominent bloggers and influencers in your industry and ask for them. If they have anything positive to say about your products, you can use their responses as testimonials and blurbs on your product pages.

Alternatively, use Tomoson.com to source these reviews directly from users.

Appeal to your ideal customer’s self-image

According to the theory of Implicit Egotism, people are naturally inclined to follow brands, people, and products that mirror their self-images.

For example, people who see themselves as outdoorsy tend to patronize outdoorsy brands like Patagonia.

According to a study in the Journal of Consumer Research, adhering to the conventions of a social group becomes a powerful source of social proof for individuals. Any brand that can portray itself as a part of these groups can win big in terms of sales and loyalty.

In simple words: If you can tailor your brand to appeal to your target audience’s self-image, you’ll sell more products.

Here are a couple of ways to do so:

1. Fine-tune your copy

The best brands spend a lot of time and money fine-tuning their copy to match the expectations of their customers.

For example, take a look at how UncommonGoods uses copy with rich details that focus on each product’s heritage and creation process, which are things its audience appreciates.

Or take a look at the copy on NastyGal.com. It’s witty and bold, values the brand's customers want to be associated with.

Figure out what values your customers identify with. Do they see themselves as goofy, funny, and the life of the party? Are they serious, ambitious, and highly motivated? Would they call themselves trendy and cued into social media?

Find the answers to these questions, then use that information to create copy that reflects those values.

2. Change your site design to fit your ideal customer’s self-image

Take a look at the site design for AmericanApparel:

All visual elements on the site are carefully chosen to mirror American Apparel and its ideal customer's self-image: chic, youthful, and modern, with a global outlook.

Or see how Smooth Sailing, a small sailing and surfing-inspired clothing store, uses colors, images, and design elements to cultivate a relaxed, surf-focused vibe:

If you can do something similar for your store, you can tap into something far more powerful than any conversion rate trick. You’ll speak directly to your customers and what they hold dear, which will not only unlock more sales, but also earn you long-lasting loyalty.

Key takeaways

Your customers are social creatures. They look to cues and validation from others before making a purchasing decision.

If you can leverage social proof on your site, then you can dramatically increase sales and conversion rates. This requires more research and introspection than simply changing a button color or layout, but the rewards are well worth it.

Has your e-commerce brand experimented with social proof on your site?