How to Optimize Conversion with 6 Persuasion Principles


How to optimize conversion of your websites and mobile apps with 6 persuasion principles

Six Powerful Persuasion Principles:

How to optimize conversion with 6 persuasion principles image from UsefulUsability.comHow to optimize conversion is a question among many website owners and app developers, to which the answer is: by applying the 6 persuasion principles as described by Robert Cialdini, PhD.

Dr. Robert B. Cialdini, Arizona State University Regents’ Professor Emeritus of Psychology and Marketing and a New York Times bestselling business author published a popular and highly acclaimed book called “Influence: the Psychology of Persuasion.” It became a national best-seller and a must read for anyone in the Psychology, UX, Marketing or Sales functions.


Because in his book he defined the root six principles that advertisers, marketing professionals, sales people and other influencers applied to get people to say “Yes.” These six persuasion principles are important for persuading people to take action, whether it be to purchase a book online, sign up for a program, download an app or even drive on the correct side of the road.

Conversion optimization professionals know and understand these powerful principles and use them to improve the UX of websites and apps. Therefore, this is the true secret of UX:

“It’s not enough to just have good website usability, you also must have good persuasion.”

The six persuasion principles:

1. Reciprocity

Reciprocity is the principle that if someone does something nice for you, you feel a need to do something nice for them. Why do we follow someone back who’s following us on Twitter, Facebook or other social media? Why when someone does a favor for you, do you feel you owe them a favor back? Why do we (most of us) pay back our debts?

The principle of reciprocity states that when someone provides us a benefit we feel we must return a benefit to that person, we ‘owe’ them. Reciprocity is present when you borrow money from your friend and you feel the need to pay your friend back. If someone says something nice about you, you feel the need to return the compliment.

In conversion optimization, reciprocity is present when you provide your website visitor with something they value, in the hope that they will provide a benefit back to you at some point. It might be a free whitepaper for them to download, a free weekly email subscription or a guide on a subject of interest. Whatever the ‘it’ is, if you provide your website visitor a benefit, something they value, then more than likely someday they will provide a benefit back to you. That benefit may not happen immediately, but the odds are the reciprocity principle will be the stimulus for them to eventually return the benefit.

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esurance uses the reciprocity persuasion principle

As the above example demonstrates, the Esurance offer to download a free app that notifies the user when to purchase, or not purchase gas to save money, even without purchasing insurance, is reciprocity in action.

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Reciprocity Conversion Optimization tactics: Use the following free items to provide something your visitor values…

Free whitepapers, cheatsheets, infographics, training videos, checklists, calculators, podcasts, enewsletters, templates, etc.

2. Commitment (and Consistency)

Commitment and Consistency is the principle that if we say we are going to do something, we feel obligated to carry through with it. Consider making a promise to someone to do something, once we have committed to that promise, we are more likely to carry out our promise, at the risk of feeling bad about ourselves if we don’t.

In conversion optimization, the commitment principle is used to commit a visitor to a course of action, whether that results in a sale now or in the future. For example, having a visitor commit now to a free trial, attending a workshop or seminar to be held in the future even if no money is requested up front, makes the visitor more likely to follow through with the action.

This principle is commonly used in the online world, especially ‘free 30 day trials’ or other offers to test a product or service. In the offline world, if you’ve shopped for a vehicle and the sales person writes down the sales price of the car, and passes you the paper and pen for you to write your price down, they are using the commitment principle.

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Hubspot uses the Commitment persuasion principle

The commitment (and consistency) principle in action is demonstrated by HubSpot, who uses a free 30 day trial to commit visitors to using their tool, in the hope they’ll eventually sign up.

Commitment Conversion Optimization tactics: Use the following to obtain your visitor’s commitment…

Free trial, signup forms for future events, reminders that visitors signed up, reminders to attend an event after signup, etc.

3. Social Proof

Social proof is the persuasion principle that links our desire to ‘follow the crowd,’ or put another way that there is safety in numbers.

Choosing a restaurant because of the greater number of people eating there (so it must be good), buying an item because more people bought that item than other similar items, and putting faith in larger versus smaller number of reviews are all examples of social proof.

We typically rely upon social proof when we are not sure about what course of action to take. The uncertainty of the situation causes us to often use the ‘follow the heard’ mentality to determine what to do. If you heard of the term “more people prefer Brand X” or “9 out of 10 doctors recommend Brand Y” you are witnessing the social proof principle in action.

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Amazon uses the social proof persuasion principle

Amazon provides an example of using social proof to help shoppers determine which of many products might be a good purchase. Note the use of the star ratings, including the number of ratings received in parenthesis. Also, the “#1 Best Seller” badge is another social proof tool.

Social Proof Conversion Optimization tactics: Use these tools to add social proof…

Star or quality ratings, top seller text, testimonials, number of downloads or users, etc.

4. Liking

Liking is the persuasion principle that says we are more likely to be influenced by people we like. And this includes people we trust or know, friends, family, relatives as well as strangers such as sports celebrities, TV or movie stars or other famous people. But the people we like don’t have to be rich or famous to have likeability. If we feel they are similar or familiar to us, or that we just trust them, then we can be influenced by them through likeability.

TV commercials that feature famous athletes were specifically created to target the liking principle. Likewise, Avon, the beauty products company was built on the liking principle: women selling Avon beauty products to their friends and family at the local, grass-roots level. Friends and neighbors are more likely to buy from their friends and neighbors. Avon’s market cap is currently $6.41 Billion, clearly likeability works.

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Amazon uses the liking persuasion principle

Avon built the foundation of their company on the liking principle. Their approach as demonstrated above is that no sales pitch or experience are necessary, you just have to be you. Other firms such as those that practice what’s known as Multi Level Marketing (MLM) are attempting to use the same liking principle to try to achieve their goals.

Liking Conversion Optimization tactics: use the liking principle in the following ways…

Build trust by providing value in your content, include testimonials from people who match your buyer Personas, add recommendations from well-known individuals, provide promotions that include celebrities, feature logos of well liked firms that use or have tried your products, etc.

5. Authority

The authority principle is based on our feeling of a sense of duty to obey those in a position of leadership or power. It includes the likelihood that we will follow recommendations of those we perceive to have authority, such as doctors, police officers, religious leaders or even our local pharmacist.

Airline pilots, military personnel, judges, doctors and even plumbers all wear uniforms of one sort or another. Why? Because the uniform they wear provides visual clues as to the authority of that individual. We are more inclined to follow the advice of an figure such as a dentist on a TV commercial if we believe they have authority.

Oddly, the authority principle works even if we logically understand that the figure we perceive as having authority does not in fact have actual authority. As an example, one popular TV commercial in the U.S. featured an actor who clearly stated at the beginning of the spot: “I’m not a doctor, but I play one on TV…”

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This successful TV commercial uses the Authority persuasion principle

This well known and successful 1986 TV commercial for Vicks featured a soap opera actor, Peter Bergman, who proclaimed at the beginning of the spot, “I’m not a doctor, but I play one on TV…” Even though Bergman was not a doctor, his perceived authority from playing a doctor on a popular TV show was strong enough to sell cough medicine to millions of people.

Need a more current example? As shown below, Redbull features Tom Pages, the X-games motocross superstar on their home page, specifically targeting the younger, extreme sports crowd with an authority figure they know and follow.

Authority persuasion principle for conversion optimization Redbull image from
Redbull uses the Authority persuasion principle

Authority Conversion Optimization tactics: include authority tools such as…

Testimonials from recognized authorities in the field, logos from well known and authoritative firms that use your products or services, badges that validate quality or authority, images that relay a sense of authority or expertise

6. Scarcity

Scarcity is a powerful principle based on our belief that rare and relatively scarce items are more valuable or attractive than those that are very common or readily at hand. Consider gold, diamonds, precious furs or limited edition cars.

In addition, the scarcity principle includes limited quantities even for common things if those things are quickly becoming scarce. As an example, consider trying to buy the last case of water in a crowded store just before a Hurricane hits when there are many others trying to buy the same water.

But scarcity has another aspect to it, which is time. We have a tendency to act more often if we are faced with a limited amount of time to acquire an item. Content that features “Act now, this offer ends in 1 day” typically converts at higher percentages than content that does not include this limited time information.

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eBay uses the scarcity persuasion principle

In 1995, eBay started a business that today is worth $73 Billion using the scarcity principle in their auction format. Knowing that time is running out to acquire an object generally causes us to not only take action, but to increase the value we perceive for that object. As the image above shows, the Tommy Hilfiger Brand on eBay prominently features a limited time event, with limited time savings and free shipping as part of the incentive to take action.

Scarcity Conversion Optimization tactics: Use the scarcity principle inclusive of value, quantity and time to incentivize action…

Clearly state the value in beneficial terms to visitors, include a limited quantity description and/or countdown, include limited time notices and/or countdowns, differentiate your product or service to highlight why it is rare or special, etc.

Conclusion: How to optimize conversion with 6 persuasion principles

Understanding how to optimize conversion by including the 6 principles of persuasion as defined by Robert Cialdini is critical for website and application success. In Robert Cialdini’s book, “Influence: The Psychology of Persuasion.” he summarized the principles impacting why people take action based on research he conducted among top sales teams, marketers, advertisers and other prominent influencers.

The 6 principles of persuasion include:

  • Reciprocity
  • Commitment
  • Social proof
  • Liking
  • Authority
  • Scarcity

Conversion optimization of websites and applications can and should utilize some or all of these persuasion principles to help visitors complete actions that are of benefit to them. But these techniques should be included as part of a usability (task flow) optimized site. Including both usability and these 6 persuasion principles will improve conversion and increase the number of satisfied users of your site or app.

For more information on how to combine usability, persuasion and findability to optimize website and application conversion see the article 3 Pillars of Website Success.


  1. Brilliant article with relevant examples and images, Every point is noteworthy. I enjoyed reading your article. thanks for sharing.

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