Photo by Aziz Acharki on Unsplash

Whether it’s seeking new investors, interviewing for our first job, or proposing marriage, all of us are in the persuasion business. If you want to convince me to take some type of action, what’s the best way to present your case?

A little over 30 years ago, psychologist Robert Cialdini set out to answer that question. Taking everything he had learned from his own research, he went undercover for three years to train for jobs in the world of “compliance professionals”: sales operators, fund-raisers, recruiters, and advertisers. He published the findings in his bestseller Influence: The Psychology of Persuasion.

The animated video below highlights Cialdini’s six “universal principles of persuasion.” 

Here, I’ve summarized the video, and added some of my own comments and lessons. If you’re interested in becoming more persuasive, here are the six principles you need to adhere to:


Simply put, reciprocity describes our desire to give something back to someone who has done something for us.

To illustrate, Cialdini cites a great example from a series of studies that took place in restaurants. It’s a common practice in many dining establishments for the waiter or waitress to bring you a small gift, like a liqueur or mint, around the same time they bring you the bill. But does such a small gesture really affect the size of your tip?

The research says yes–by a large margin. In one study, giving people a mint at the end of a meal typically increased tips by about 3 percent. When the “gift” was increased to two mints, the size of the tip more than quadrupled–by a rate of 14 percent! But one action had an even greater effect.

The waiter would give a mint, begin to walk away, then turn back and say: For you nice people, here’s an extra mint. This small action caused tips to increase by a rate of 23 percent!

“Influence,” points out Martin, “not by what was given, but how it was given.”

Lesson: The key to reciprocation is to make sure your giving is personalized and unexpected.

In the digital age, it’s oh-so-easy to click a button and follow someone on social media or send a generic invitation to connect. But you won’t create much influence that way, even if the person follows you back.

If connecting with someone is important to you, try commenting on his or her blog. Or sending a short, personalized message telling them why you want to connect. Better yet, share some of their content and let them know why you found it valuable. (Hint, hint.)

2. SCARCITY (3:06)

The rule of supply and demand: People want more of the things there are less of. This hype has even spawned its own four-letter word–FOMO (Fear of Missing Out).

For example, British Airways announced in 2003 they would no longer be operating the twice daily London-New York Concord flight because it had become “uneconomical.” What was the result?

Sales shot up the following day.

Nothing had changed, the Concord flight had simply became a (suddenly) scarce resource.

Lesson: Define your unique selling point (USP). More importantly, outline what your potential customer/investor/marriage mate stands to lose if he or she doesn’t take advantage of your proposition.

3. AUTHORITY (4:10)

People follow the lead of credible, knowledgeable experts.

Cialdini cites examples like how certain medical professionals post their degrees and certificates on their office walls, to remind us why we need to listen to them.

Chances are, many of you are reading this article because of the phrase in the headline “proven by science.” I really like the following comment by Dana Hattie, posted on YouTube under Cialdini’s video:

A new study shows that the odds of you believing something greatly increase when the sentence begins with “A new study shows that.”

Lesson: Develop a strategy that signals to others why we should listen to you, ideally drawing from outside sources.

If your company doesn’t yet have a blog, you’re already late to the party. When you share valuable answers to the questions I’m researching via your website, I’m likely to come back. When commenters on other sites and other active social media-ites begin to claim you as an authority, complete with links to your homepage, even better.

Once I’m ready to drop some cash, guess who I’ll buy from?


People like to be consistent with what they’ve previously said or done. This principle is also described as “commitment.”

For example, one experiment involved asking introductory psychology students to take part in a study session on thinking processes–at 7:00 in the morning. The first group of students were called and told right away that the session would begin promptly at 7:00 a.m. Not surprisingly, only 24 percent agreed to participate.

The second group of students was first told details about the study and the session leaders’ desire for their participation. The early time was only mentioned after they agreed to participate. How many students agreed? Fifty-six percent. When offered an opportunity to back out, none of them did. Ninety-five percent of those students followed through and showed up for the session.

Cialdini’s research indicates that the more voluntary and public a commitment, the more effective.

Lesson: Look for voluntary, active, and public commitments from others. If possible, get them to put something in writing.

For example, you could try asking leads to try your product for a specified amount of time–absolutely free. They choose the amount of time they’ll use the product (up to a specific limit), and in exchange agree to submit comments about their experience.

You’ve now turned those leads into customers. If your product is good, many will become paying customers.

5. LIKING (7:40)

People prefer to say yes to those they like. (It’s rule No. 1 of successful negotiations.)

Seems simple enough. But what causes us to like others? Cialdini’s research points to three factors. We like people who:

  • are similar to us
  • pay us compliments
  • cooperate with us to reach future goals

We are drawn to those with whom we share something in common–it’s why we get excited when we meet someone from our same hometown. If those people get vocal about what they like about us and are easy to work with, it’s a home run.

Lesson: People do business with other people, not businesses.

Social media makes it easier than ever to learn about potential partners. Find out what you have in common, tell them why you like them, and look for a way to work together.

6. CONSENSUS (9:05)

When individuals are uncertain, they will look to the actions of others to help them make decisions.

Cialdini cites a study that analyzed hotel guests and their reuse of towels and linens. After trying out a number of different signs in the bathroom, they found the following note most effective:

Seventy-five percent of people staying in this room reuse their towel.

The key was not just the positive peer pressure, but the fact that these people shared a very specific trait–they stayed in the very same room. You might not think this sign would have such a great effect, but the facts say otherwise:

This simple message was responsible for a 33 percent increase in towel reuse.

Lesson: By pointing to what many others (especially similar others) are already doing, you can help sway someone’s decision in your favor.

For example, a salesperson who has identified his or her company’s target customers is already halfway there. Look for traits those customers have in common. Use available data to track who is buying and sharing news about your company. Then, as your business grows, use that data and the decisions of “similar” others to help convince the rest.

We work daily to convince others of our opinion. A few small changes using the above research could greatly increase your effectiveness.

Just don’t forget to invite me to the wedding.

Enjoy this post? Check out my book, EQ Applied, which uses fascinating research and compelling stories to illustrate what emotional intelligence looks like in everyday life.

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