With the overwhelming amount of options and material we are bombarded with it is increasingly important to maximise your opportunity to sell.

Did you know most purchases are made emotionally, with then logic applied to justify the decision. Conversion optimisation is about leveraging both these things.

At the very heart of conversion optimisation principles and techniques, you will find persuasion.

Whether you want your audience to sign up for a newsletter or buy a gift, many conversion optimisation tests are based on improving the power of your persuasion.

It therefore follows that the science of persuasion can significantly help optimise your user experience and drive growth for your eCommerce business.

Introducing Cialdini’s Six Principles

When Robert Cialdini published Influence: the Psychology of Persuasion in 1984, it created quite a storm; never before had a scientist provided such a clear guide to affecting human behaviour associated to the art of persuasion.  

Today – nearly forty years and three million copies later – it remains as relevant as ever, providing marketers with an amazing platform for improving how they persuade customers.

The book presents six key principles:

These principles of persuasion underpin many of the CRO tests you will look to perform and understanding them will allow you to better shape those tests.

To understand the Cialdini’s 6 principles of persuasion more deeply, let’s look at each one in turn. For each principle we will provide you with:

  • An overview of the principle.
  • An explanation of how it can be used.
  • An example of where it has been used to good effect.

1. Reciprocity | You’ve got to give to get

Reciprocity Overview

If you do something for a person – with no conditions attached – they are far more likely to do something for you in return. By paying forward there is a psychological need to repay, inbuilt into most people.

Gifting Flowers

Reciprocity Explanation

We see this in action every day, but it is also supported by overwhelming experimental evidence: one study focused on reciprocity by testing mints at the end of a meal in a restaurant.

Group 1 had servers giving mints along with the check, making no mention of the mints themselves. This increased tips by around 3% against the control group.

Group 2 had servers bring out two mints personally by hand, and verbally asked if the customers would “like a mint before they leave?” – Tips increased by 14% against the control group.

The last group had the servers bring out the check first along with a few mints. A short time afterward, the server came back with more mints, and let customers know that they had brought out more in case they wanted another. This last group saw a 21% increase over the original.

This told us that reciprocity will improve performance, personalised reciprocity will further increase it and unexpected reciprocity mixed with a personalised approach, improved conversion rate even further!

You can run your own reciprocity test by simply saying ‘good morning’ to strangers. The act of greeting makes the stranger feel oblige to take part!

Researchers bump heads over the underlying mechanisms of reciprocity: some believe it has evolved as a way of rewarding pro-social behaviour, while others suggest humans simply hate being indebted to others.

What researchers all agree on is that reciprocity is one of the most universally effective means of persuasion.  

Reciprocity Example

Neil Patel sells an SEO tool that helps businesses understand and improve their website’s performance. But to market it, he gives away a huge amount of detailed, highly-actionable content for free.

Neil Patel Website Screenshot

The rationale? Not every prospective customer understands the value his service provides, and this content helps contextualise that offering.

People will be drawn to his business by the promise of free content that’s relevant to their needs; and through the magic of reciprocity, they will soon feel compelled to sign up to his paid service.

The ecommerce CRO takeaway

Giving away free discount codes on first time orders, bonus gifts, free delivery, useful guides to choosing products, post-sale reward schemes and more, can be a powerful tool for growing your transactions and conversion rate. The more value they provide – the more personalised you can make them – the more effective this strategy will be.

2. Scarcity | We want what we can’t have

Scarcity Overview

People feel more urgently compelled to buy something if its availability is limited, either by time or volume.

Special Price In Store Window

Scarcity Explanation

If a product or service is fully stocked, we can take our time considering alternatives; if there are ‘Only 3 left’, we are suddenly in a rush, and therefore more likely to act impulsively.  

In one classic study, researchers presented participants with two jars of cookies. One had ten in it, the other two. It found that participants would prefer a jar of two cookies to an identical jar with 10 cookies in it, even though they were the exact same cookie – inferring that the scarcer cookies must be in higher demand, and therefore better quality.We call this effect FOMO or Fear Of Missing Out.

Scarcity also creates an air of exclusivity that is appealing to many consumers; this is why high-end products in industries like fashion are often produced in ‘limited editions’.

Scarcity Example

Black Friday may be the perfect example of scarcity in action.

Consider how this marketing email combines the promise of value – i.e. heavy discounts – with an extremely pressurised time limit, compelling the audience to buy before they miss out on the best deals of the year:

Black Friday Sale Screenshot

The ecommerce CRO takeaway

Scarcity signals can increase conversions, but false-scarcity tactics are increasingly prevalent online. When you signal scarcity, it needs to be authentic: if consumers become confident that their ‘last chance to buy’will be back again next week, the effect really starts to wear off. So using ‘limited stock’ messages, time-framed sales, ‘exclusives’ and more, can help your ecommerce website demonstrate Cialdini’s scarcity persuasion technique

3. Authority | Confidence Is Key

Authority Overview

Simply put, people want to buy from credible, trustworthy sources.

Trust written in sand

Authority Explanation 

When making decisions, we rarely have enough knowledge ourselves to make very fine distinctions of quality; how could Average Joe really determine whether one pair of expensive trainers is better than another?

To resolve this problem, we look for signals of authority, using them as a proxy for quality.

This is why brands spend so much on celebrity endorsements: research has repeatedly demonstrated how willing we are to outsource our decisions to authoritative individuals, even when their judgement goes directly against our own.  

Authority Example

Many B2B businesses use the prestige of brands they work with to signal their authority.

Consider how Stripe – an online payment provider – includes a list of impressive customers at the top of its website:

Stripe Website Screenshot Of Logos

The effect is to reassure anyone in doubt that Stripe is experienced, skilled and authoritative. And given their exponential growth, it clearly works.

Or how Under Armour utilises Anthony Joshua to demonstrate its commitment to quality and fitness. ‘If it’s good enough for Joshua its good enough for me.’

However not all endorsements have to be by celebrities. A health product reviewed, researched or endorsed by a doctor or medical body will have more clout than one that does not.

The ecommerce CRO takeaway

Successful businesses take every opportunity to signal their authority: this could be through celebrity endorsements; high-level brand logos; medical evidence; or research and development.

Most importantly, you need to signal the right kind of authority for your audience: scientific evidence is rarely of interest to fashionistas, but a sports buff will definitely want to hear about the evidence you leveraged in your designs.

Review your business for authoritative signals to a user and think on how this can be better presented in copy and visuals.

4. Consistency | The power of commitment

Consistency Overview

People have a deep need to remain consistent with their previous claims and actions. No one really likes to be seen to have been wrong!

Consistency Explanation 

Small commitments often create a precedent for much larger commitments.

Once someone has committed to a path, even by the smallest step, they are more inclined to continue on it than walk another.

Agreeing to a free consultation, for example, may lay the groundwork for a much more substantial investment of time and resources later down the line. Agreeing to a sample or brochure increases the likelihood of a user going on to make the purchase. This likelihood is increased when the choices are made public.

One study demonstrated that simply making patients write down their own appointment times decreased medical no-shows by 18%; the simple act of directly committing in this way made it harder for them to renege later on.

Some theorists claim the desire for self-continuity boils down to social pressure: if we are seen as inconsistent, we will be deemed untrustworthy. Others stress the importance of continuity in our self-image: we have a deep psychological need to believe our identity is unified and singular. That our opinion is the right one.

Regardless, the power of past decisions to guide future ones is inarguable. And for marketers, it is extremely powerful.

Consistency Example

MyJobQuote connects tradesmen with clients in the UK. But rather than asking users to commit to a hire right away, they ease their audience in by offering a free quote.

All the visitor has to do is enter their postcode; many users’ computers will autofill it, making this almost literally effortless. But once they’ve begun the process with this small commitment, the desire for self-consistency will bias them towards actually booking a job.

My Job Quote Website Screenshot

The ecommerce CRO takeaway

Changing the text on your pop-up from ‘no thank you’ to ‘I’ll do it later’ will plant the seed and is the smallest step on the road to sign up.

Social media sharing of wish lists, products and reviews can help a customer become an advocate. For larger items, split payment or getting a finance quote rather than the purchase can help reduce the perceived financial commitment and improve conversion rate.

5. Liking | Connection and Reflection

Liking Overview

People are more easily persuaded by people and products they like.

Thumb out of computer

Liking Explanation

Generally speaking Cialdinis principle of ‘liking’ boils down to someone feeling that the person or brand is similar to us in some way or has an affinity towards it.  Whether it’s their interests, principles, temperament, tone or even just their name. Indeed, research suggests people are so drawn to things which mirror their own traits that people named Denis are actually more likely than others to become a dentist. Or why good sales people will take the time to build rapport and find ‘common ground.’

You don’t need to directly mirror a person back to persuade though. You can make people like your brand simply by aligning with a value or belief they hold dear, or showing a similar sensibility in your design and copy.  

For example a business can be ‘liked’ for taking a serious approach to a serious subject. Or conversely others can be liked for taking a more light-hearted approach to a serios or boring subject – just look at how the playful Innocent Smoothies grew significantly from creating a likeable brand and tone. They made reading a drink label more fun than other competitors (not something we ever thought of committing to an article before!). 

Liking Example

Chilly’s make aesthetic, reusable water bottles. But rather than presenting the value they provide rationally, they make an emotional, value-driven case to their audience for why Chilly’s bottles are worth the investment.

Their website’s About page heavily prioritises the ‘mission’ they are on to reduce plastic usage, and for countless consumers, this makes them instantly more likable – and therefore more persuasive.

Chillys Website Screenshot

The ecommerce CRO takeaway

Liking is all about understanding your audience. What kind of personality will they be drawn to? What are their beliefs and aspirations? Creating a clear, direct connection with consumers is the key to long-term loyalty.

Review your content and ask yourself ‘do I sound like my customers?’ – Do you write to them or at them? Is your content helpful? Do the images create a likeable product? Are your brand influencers liked by your target demographic? Do you do any good in the world and if so is that shared?

There are lots of ways of making a brand and product more likeable to a user.

6. Social Proof | I’ll have what she’s having

Social Proof Overview

When people are uncertain, they look to others for guidance about what to do.

Social Proof Explanation

The underlying dynamics of consensus are similar to authority: we don’t have sufficient information or expertise to determine what is high quality or acceptable, so we outsource judgement to our peers.

In part, social proof is about a desire to fit in. But it’s also about confidence: learning that many other people have had a positive experience with a given brand is deeply reassuring and validating.

In many industries, social proof is not just useful but essential; 90% of consumers consult online reviews and ask their friends opinions before frequenting a restaurant.

Social Proof Example

Artfinder sells a variety of art to consumers across the globe, and their website is filled with smart social proofing techniques.

Consider how this page combines two kinds of social proof here. There are reviews of the artist – which lets the visitor know they will receive reliable, high-quality service. But there is also a heart metric, telling the visitor how many of their fellow users have singled this piece out and ‘love’ it.

Art Finder Website Screenshot

The ecommerce CRO takeaway

Social proof is key for an eCommerce site, but to really have an impact you should seek to tie that social proof to a real, tangible community.

Review & reputation management is key.

Social proof is often anonymous, and this makes it less effective. Try to show your audience who has bought an item, and why you should trust their taste and want to emulate it.

And this leads us onto the seventh (!) principle…

Bonus Round: The Unity Principle

Unity Overview

You’ll choose products or services based on the communities and social groups you have strong affinity towards.

Group of hands in a circle

Unity Explanation

In 2016, over three decades after his book’s initial release, Cialdini announced that there was a seventh principle: Unity and Community. Based on his continuing research, he argued that a sense of shared identity is as if not more powerful than any of his original principles.

Simply put, the more we identify with a group or community, the more easily we are persuaded by them. And for businesses, this carries a vital lesson.

Being persuasive and increasing your conversions isn’t always about clever marketing tricks: it is about building a brand that means something to your audience. It’s great to have authority and for consumers to like you, but these attributes are far more powerful when put to service of building a sense of shared value and investment.

It’s fitting that Cialdini only presented this principle in the ‘10s, because it is such a timely principle: many of today’s biggest businesses rely on growing communities and encouraging consumers to identify with their brand. From Netflix and YouTube to challengers like Peloton and Monzo, the promise of joining a community is the single most persuasive offer a brand today can make.

Look at the industry of cross-fit. This exercise regime and associated products has been built on the sense of shared community.

Simply put, a goth is more likely to buy goth clothes brands to appear more goth.

The ecommerce CRO takeaway

Our advice to business owners is this: learn Cialdini’s original principles, and use them as much as you can. But once you have, try to find ways to use them in service of building a unified brand community. This can be achieved by Loyalty Rewards, Community social media interaction. Customer stories, shared missions and much more.

Persuasion – and conversion – should never be done in isolation: it should always be about a larger, more ambitious strategic goal. 

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