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How to Use Cialdini’s 6 Principles of Persuasion to Boost Conversions

Cialdini's principles

Back in 1984, Dr. Robert B. Cialdini wrote a book called Influence: The Psychology of Persuasion. Since then, it’s been widely hailed as a seminal book on marketing—something everyone in conversion optimization should read.

What are Cialdini’s 6 Principles of Persuasion?

Cialdini’s 6 Principles of Influence are reciprocity, commitment or consistency, consensus or social proof, authority, liking, and scarcity.

More than three decades after the book’s publication, its six principles have been adapted to Internet marketing, too, especially the business of conversion rates.

This makes sense: Conversions are all about persuasions. When a user casually visits your website, you want to turn them into a shopper, and then a buyer.

In the world of conversions, every little bit of persuasion counts. Here’s how you can use Cialdini’s 6 Principles of Influence to boost conversions.

Update: Cialdini has since published a 7th principle: Unity

1. Reciprocity: Give a little something to get a little something in return.

Cialdini’s first principle of persuasion states that human beings are wired to return favors and pay back debts—to treat others as they’ve treated us.

The idea of reciprocity says that people, by nature, feel obliged to provide discounts or concessions to others if they’ve received favors from those same people. Psychology explains this by stressing that humans simply hate to feel indebted to others!

Let’s say that you’re running a popular blog that offers readers highly actionable and practical information to improve their lives. All of this information is offered for free to site visitors.

Based on the idea of reciprocity, your blog makes site visitors more likely to feel obligated to buy something from your site, providing you with an eventual conversion.

Example of reciprocity

One of the best examples of this Cialdini principle in action is the Brian Dean’s website, Backlinko. Dean’s website is centered on his blog, which is single-mindedly focused on giving its readers tips, advice, and suggestions on how they can be more successful webmasters and SEO analysts.

backlinko homepage

Thanks to his very informative content, regular site visitors are more likely to sign up for his (paid) training courses or contact him for consulting services.

2. Commitment: People want their beliefs to be consistent with their values.

The principle of commitment declares that humans have a deep need to be seen as consistent. As such, once we’ve publicly committed to something or someone, we’re much more likely to go through and deliver on that commitment (hence, consistency).

From a psychological perspective, this can be explained by the fact that people have aligned commitment with their self-image. Marketers, of course, have figured out how to use this second Cialdini principle to obtain greater conversion rates.

By getting site visitors to commit to something relatively small (and usually free), like a guide or whitepaper, they increase the likelihood that those site visitors will eventually see themselves as customers. That change in self-perception makes it easier to follow up with an offer for a paid product or service. (This is similar to the “foot in the door” technique.)

Example of commitment

A striking and memorable example of this Cialdini principle in action can be found on the Copyblogger website. Copyblogger is the brainchild of Brian Clark. While it’s a popular blog, it’s really a software and training organization that sells content marketing software through Copyblogger Media.

Right on the homepage, you’ll notice a big headline urging you to grab the company’s free online marketing course. Just enter your email address:

example of free offer on homepage to engage commitment principle.

Clearly, this is a form of public commitment meant to get you to see yourself as a customer of the company. It’ll raise the chances that you’ll go on to purchase one of their services.

3. Social Proof: There’s nothing like feeling validated based on what others are doing.

Cialdini defined social proof as people doing what they observe other people doing. It’s safety in numbers.

For instance, if our coworkers work late, we’re likelier to do the same. If a particular eatery is always full of people, we’re likelier to give that establishment a try.

We’re even more influenced by this principle if:

  • We’re unsure of ourselves.
  • The people we observe seem similar to us.

Social psychology is rife with experiments that illustrate this unavoidable, human phenomenon, but a classic one is this 1960s elevator experiment:


Basically, whatever the majority of people do in an elevator, an individual who joins the group will copy.

For example, if the group looks to the back of the elevator, the individual will do the same, even if it looks funny. Most people refuse to think or behave independently.

Example of social proof

One of the most powerful ways to use social proof is through so-called “wisdom-of-the-crowds.” Take Modcloth. Their product pages include not just reviews but also a counter that tallies the number of site visitors who have “hearted” a particular item:

example of ecommerce product page using social proof.

A previous tactic by the retailer allowed shoppers to vote on which styles they thought should be put into production. Such styles were awarded a “Be the Buyer” badge, which doubled the rate of conversion rate compared to items with no badge.

4. Authority: You will obey me!

Ever wonder why we a tendency to obey authority figures, even if they’re objectionable and ask others to commit objectionable acts? It’s human nature!

Accessories, such as job titles (e.g. Dr.) and uniforms, infuse an air of authority, making the average person more likely to accept what that person says. You can see this in commercials that, for example, use doctors to front their ad campaigns.

Example of authority

ShoeDazzle, which specializes in women’s shoes and accessories, relies on this principle. The company was co-founded by Kim Kardashian, who also serves as one of ShoeDazzle’s chief fashion stylists.

Even though the company was also founded by serial entrepreneur Brian S. Lee and attorney Robert Shapiro, that wasn’t going to help ShoeDazzle attract conversions. For the target demographic—young women obsessed with shoes—Lee and Shapiro aren’t authority figures.

That’s why the company brought in Kardashian as a co-founder. She’s an authority figure for young women shoppers.

5. Liking: The more you like someone, the more you’ll be persuaded by them.

What does it matter if you like someone? According to Cialdini, it affects the chances of you being influenced by that individual. Welcome to Cialdini principle number five: liking. Liking is based on sharing something similar or a more superficial interest, like physical attractiveness.

This principle can be applied to conversions in the following way: A company that wants to boost conversion rates should create a great “About Us” page.

That sounds absurd, but it makes sense when you understand that a company’s “About Us” page is an opportunity to tell potential buyers about the similarities between its staff and site visitors. Since similarity is a key building block of liking, an effective “About Us” page is vital.

Let’s take a look at a case study.

Example of liking

This case study centers on a company called PetRelocation. They help pet owners all over the world move their pets from country to country.

The company’s “About Us” page is full of staff bios, and every bio emphasizes not only the staff’s love of dogs, but also humanizes managers and employees by including hobbies and other personal details.

example of about us page to increase liking.

The effort increased the company’s likeability, which in turn boosted the conversion rate of site visitors.

Some businesses succeed with the liking principle on a grand scale. Richard Branson’s Virgin Group is liked by millions of loyal consumers who enjoy its mobile phone service (Virgin Mobile) and airline (Virgin Atlantic), among other businesses.

6. Scarcity: When you believe something is in short supply…You want it more!

Here we are, at the end of Cialdini’s authoritative list of persuasion principles. Scarcity is the perception that products are more attractive when their availability is limited.

We’re likelier to purchase something if we’re informed that it’s the “last one” or that a “special deal” will soon expire. In short, we hate to miss out, and that fear is a powerful motivator to encourage us to act quickly.

Examples of scarcity

Scarcity is one of the most popular Cialdini principles. Companies use it over and over again to boost conversions. This is a common tactic on travel booking sites:

Booking.com employs the scarcity principle in many ways:

  • “You missed it! We reserved our last available room at this property.”
  • “Our availability in Dublin is low on your dates – lock in a great price before it’s too late.”
  • “Today 45% off.”
  • “5 people are looking right now.”
  • “In high demand – only 4 rooms left on our site!”

There’s also “time-limited scarcity.” Monetate has a great example of this principle. A blurb that reads, “Offer Ends in…, ” with a countdown resulted in an average order value (AOV) increase of 0.07%.

While a tiny increase, for this large online retailer, that small margin in AOV proved to be a “million-dollar campaign.” (Read more here.)

But be careful: Never use fake scarcity—made-up claims of limited supplies or expiring discounts. Your site visitors will see right through you.


These 6 Principles of Influence have been used for decades by businesses and marketers to get you, the consumer, to part with your hard-earned money. Since the explosion of ecommerce, Cialdini’s six principles have been adopted there, too.

Pay close attention to these principles. Learn what they’re about and how to apply them to your website. Don’t be afraid to give your potential customers a free sample or two, and definitely tell them if your products won’t be available for much longer or at certain prices.

Used properly, you’ll enjoy a boost in your conversions. Act now—before it’s too late!

Update: Cialdini has since published a 7th principle: Unity

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  1. If you change a paragraph or two, this post could just as easily be about dating. Excellent info.

  2. Great post Peep! I really enjoyed the article. An undeniable example of social proof is the success of Facebook. The entire user experience and massive growth is heavily based upon the principle of social proof. Even their new “Facebook Sponsored Stories” feature. The stories are only shared with friends you know and it appears at the top of all your friends feeds. When friends see the recommendation coming from another friend they are more likely to read it, comment, and share it. This is social proof in action!

    Thnx again, keep it coming!

    1. Avatar photo

      Thanks Sal!

      Indeed. And wall posts with tons of likes and comments attract more likes and comments.. and so on :)

  3. Peep – always enjoy reading your articles. Keep the good stuff coming ;)

  4. Hi Peep,

    This is my first time on your site — joined your email list as well.

    Fantastic extrapolation of Cialdini’s marketing classic.



  5. Amazing posts peep,just like always. There is a lot to say about how to apply these principles to increase conversions.

    Adding to the “liking principle”:

    We know from neuroscience that whenever we are faced with a new situation/event or meeting someone for the first time our reptilian brain is alarmed to evaluate whether its a threatening event/person or friendly (in our case, landing on a new website). By quickly building rapport and showing empathy (through our value proposition/headline, our lead paragraph) we can open a window to start persuading the decision maker (the old brain) and start getting them to like us. It usually translates in low bounce rates on a page for new visitors.

    Looking forward for future posts peep.

    Make your day great

    1. Avatar photo

      Good insight. Definitely if we like the person selling us something, it’ll lower our guard and we’ll be more receptive to the message.

  6. Great Post as always Peep, I think this is the only blog where I check back every other day to see if there is something new, as I believe you don’t send out emails for each post you write. I get your email a week combining couple of posts and I find that different and a new approach to email marketing.
    I think social proof is most important, as it’s very comfortable to buy something you know other are buying. I think urban outfitters are doing an excellent job with this, they have a review tab with reviewers photos wearing the same product.
    Thanks for sharing..

    1. Avatar photo

      Thanks! Indeed, I send newsletters only once a week.

  7. Good stuff. I love Cialdini.

  8. something great to learn here. These are called timeless business principles. They will always be effective. I will surely share this. I like the idea of RECIPROCITY. It only thought as not to be selfish marketers.

  9. Great post Peep

    Always find myself coming back here :-)

    For small businesses, one-person set-ups, or those without the authority/confidence yet in their sector – persuasion selling strategies online can be a daunting intangible – systems that are hard to set up and equally hard to measure.

    In that context, have you ever thought of releasing a step-by-step course of simple techniques businesses could use to increase their website conversions – especially now traffic is so precious with all the Google changes – just a thought?

    Good stuff as always and your book is excellent.



    1. Avatar photo

      Thanks Loz!

      Indeed, a course is in the making;)

  10. Would love to see examples of how to use scarcity when you’re only selling one product, such as an eBook. Great post and thank you.

    1. Avatar photo

      You could
      * Sell it only until date X
      * Give limited bonuses to Y buyers
      * Give extras to people that buy before Z date
      .. and so on :)

  11. Great book and some useful tips in the article :-) I’d also recommend reading Kahneman’s “Thinking fast and slow”, lots of insights into the way we think and act to be found there .. and used to improve our marketing efforts :-)

  12. Dear Peep Laja, thank you for your great article. We are proud publishers of Czech translation of Cialdini’s “Influence” book (http://melvil.cz/kniha-zbrane-vlivu) and would like to ask you for permission for translating and publishing your post in Czech language – on our blog. Is it possible? Thanks!

  13. Peep,
    What a fantastic article. I just recently came across Cialdini’s book at the library, read it, and was blown away. It really changed my thinking about many situations, including conversion rates. I actually wrote myself a “6 Principles” assessment where I judged my website based on these principles! I’ve also been a follower of your blog for the last few months, so this post really clicked for me.

    I think it’s worth going into any situation (selling, dating, job interview, friendly debate) keeping the six principles of persuasion in mind. I have seen positive results in my own interactions with people. Thanks for an excellent post!

  14. A great blog with some great advice. Nice one

  15. This guy have indirectly taught me more about marketing than I ever thought possible. If you want to get a serious education on the power of persuasion listen to his audio and buy his book YES! The case studies are unreal. All can be applied to your business for awesome results.

    GREAT post. Huge Cialdini fan.

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