Robert Cialdini is a renowned social psychologist who is particularly well known for his research on persuasion and influence. He is the author of numerous, heavily cited academic papers on the subject, and his book, Influence: The Psychology of Persuasion focuses on how to influence your audience’s decision making. He distills his many years of research on the subject into six principles of influence. They are:

  1. Reciprocation
  2. Commitment and consistency
  3. Social proof
  4. Liking
  5. Authority
  6. Scarcity

These principles have been used and proven successful in many applications and industries, including, but not limited to, sales, writing, marketing, and more. While the principles of influence can and are applied to many things we do here at Zion & Zion, we’ve found these principles particularly useful in user experience (UX). Let’s dive down into what each principle of influence is, and how each can be applied to UX.


We feel obligated to repay someone when they have given us something.

Real life example:

The classic story here is about a car salesman who had one trick: a Coke. The car salesman talks to the customer, then goes over to a Coke machine, pulls out a dollar from his pocket, buys a Coke and hands it to the customer.

What happens next? The customer is much more likely to buy the car from the salesman. I know, that $1 Coke isn’t even close to the price of the car. But as humans, we feel obligated to repay someone when they have done something for us—even if it’s as small as buying us a Coke. A statistical note. We’re not saying that if someone buys you a Coke that you’ll buy a car from them. What we’re saying is that over repeated trials, the act of buying someone a Coke has a statistically significant effect on the percentage of people that will buy a car.

UX application:

How can you apply this to UX? One common way to use reciprocation is through a content strategy where your brand provides useful information to readers. The mere act of curating and supplying quality information on your website and answering user questions can trigger reciprocation. You help readers out by providing information they need, and when the time comes for them to make a purchase, they may be more likely to go with you over a competitor. Is this a fail-safe solution to grow your sales? Of course not; but the user may feel an underlying pull of obligation to do business with you because you helped them.

Commitment and Consistency

Once we make a decision or take a stand, we have a tendency to want to have our future actions consistent with our previous ones.

Real life example:

It’s simple. People want to stay true to their word and be consistent. This principle works best when someone takes a stand publicly or verbally.

Amongst many studies that have been done over the years is one where a group of people were asked to wear a ribbon in support of cancer for a week. They did it and thought the study was over. After some time, all members of the group were asked to donate money to help fight cancer. Compared to the control group who were not asked to wear the ribbons, the group who wore the ribbons donated significantly more money overall. Why? They felt committed to supporting the cause at that point because they had publically supported it previously.

Once a person takes a stand for a cause, they see themselves as that type of person and stay true to it.

UX application:

When I think of the principle of commitment and consistency, I think of presidential candidates. Since at the time this article was being written, we were in the middle of a presidential election, there were examples of this everywhere.

The Hillary Clinton website is a great example.


Example of commitment and consistency

As soon as you get to the website, you get a popup asking you to agree with what she stands for. By clicking the button saying “I agree,” you’re more likely to stay consistent in that belief at a later date. In this case, that means you’re more likely to vote for Hillary. A statistical note. We’re not saying that everyone that clicks the button will vote for Hillary. What we’re saying is that over repeated trials, the act of someone clicking the button has a statistically significant effect on the percentage of people that will vote for Hillary.

Social Proof

When we’re not sure of something, we validate our decisions based on what other people think is correct.

Real life example:

This one’s a simple concept. You’re in a new city and you’re hungry. How do you decide where to eat? Do you look up places on Yelp? Do you look for the place with the longest line? Do you ask some locals for a suggestion? Either way, you’re using the opinions of others to help you make a decision (i.e. social proof).

UX application:

There are many ways to include social proof on your website. You can include testimonials, ratings from sites like Yelp or Angie’s List, or social media posts from customers to show how much others like your brand, company or product. This will make new visitors think, “these people like this brand, so I probably will too.”


We say “yes” to individuals we know and like.

Real life example:

Imagine you’re at a Tupperware party. Do you want Tupperware? Probably not. If your friend hosts a Tupperware party, do you buy Tupperware? I bet you do. Cialdini references a Tupperware party as a classic example of liking because liking your friend increases the chances that you will purchase the Tupperware. It’s as simple as that.

This principle also works even if you don’t know the person, but find them physically attractive. It’s pretty shallow of us, yes, but we’re more likely to purchase from someone we’re attracted to.

UX application:

You can go about this one in many ways. It could be as simple as having an attractive, likeable, smiling face on your homepage. You can also make your brand more personable and likeable. Think about it, I’m sure there’s a company or product out there that you are loyal to solely because you like their brand. Their product or service may not be any better than competitors, but you like their brand, so you stay loyal.

So how can you apply this to your brand and site? Small things like an “about” or “team” page that shows the personality of your company can make a big difference. We do this with our site. People often mention how much they enjoy getting to know the personality of our team through the team page.

You can also achieve liking through the copy of your site. Let’s say you have an email newsletter sign up on your site. You can say, “Sign up for our newsletter,” and hope for the best. Or, you can say, “Want to be pen pals? We do too.” How about, “We like you. Let’s stay in touch.”

However you choose to go about it, talk to your audience like they are a friend or colleague, and they will like you for it.


We follow and react to authority symbols.

Real life example:

There have been a lot of studies done on how people react to symbols of authority. The Milgram Experiment is likely one of the most well-know (and depressing, if you ask me). Without going into too much detail, the study focuses on how far ordinary people will go in following what an authority figure tells them to do—even if the result is hurting someone else.

The results? People will go pretty far. You can read about the study in more detail and watch a video of it here.

A less depressing example is one involving a police officer and an expired parking meter. The study showed that when a complete stranger (non-authority figure) suggests that you pay a stranger’s expired parking meter, less than half of people complied. However, when an authority figure (a police officer) suggests the same thing, almost 100% of people do it.

UX application:

There are many ways to achieve authority on your website. The use of simple icons, like a BBB (Better Business Bureau) rating or association logos work. If your company has uniforms, showing a person in your uniform helps position them as an authority figure.


If something is less available to us, we want it more.

Real life example:

There have been a lot of studies done to show how scarcity works. A simple example is a job posting for serving positions at a restaurant. The study posted two job postings, which were ultimately for the same job. One said there were many positions open, while the other advertised only a few positions left.

Which job got the most applicants? The second one. People assume if there aren’t many positions left, it must be better.

UX application:

An example that I’m working with right now is for a school that is accepting applications. They have an application deadline, so we could simply say, “Applications due May 25th.” However, we opted to use scarcity and are using a ticker to count down the number of days left to apply: “Application deadline: 23 days.” The countdown leads to users developing a sense of diminishing availability.

If you have an ecommerce site, there are a lot more ways you can implement scarcity. One way is to show the amount of that specific product left in stock: “Only three left in stock.” A simpler option is to use verbiage for an offer or product that is going away soon, “limited time offer,” or “get it before it’s gone.” A simple message like that can help put the idea in your user’s mind that if they don’t get it now, they might not be able to get it.

Putting it Into Practice

I’ve outlined a few of the ways you can apply Cialdini’s principles of influence to user experience, but the list doesn’t end here. Go out there, and put these principles to use and help influence your users. Just remember to always influence responsibly.