How companies leverage psychology to steer our choices

Psychology Jul 2, 2018

An introduction to Cialdini’s six scientific persuasion principles

When you understand these persuasion principles, you will start noticing how common they are.

In the 70s, an American researcher called Robert Cialdini had a hunch. Cialdini believed there was a science to how people are persuaded. He decided to study the factors influencing people to respond with “Yes” to requests.

For three years Cialdini went undercover to study people who make a living persuading others. Cialdini took on many jobs, such as used car salesman, telemarketer and fund raiser. At each job he carefully took notes about the tactics he learned. The undercover experience formed the foundation for many years of follow-up research and scientific experiments.

The research of Cialdini revealed universal principles that influence human behavior: Cialdini’s six principles of persuasion. Once you know them, you will notice them everywhere.

You will see these principles in action when buying a book at a store. When having dinner at a restaurant or going to the movies. When booking a flight or getting a new subscription.

I will explain Cialdini’s six principles of persuasion using common examples everyone should be able to relate to.

Principle 1: Social proof

“There is safety in following a path carved by others”

When making a decision, it is easy to follow others. If many people like something, it can’t be all that bad right?

A high review rating on Amazon is an example of social proof. If many people like a book, we believe there is a high chance we will like it too. We are not as special as we think.

Another example of social proof is displaying the amount of Facebook likes your company has. If so many people like your Facebook page, the company surely must be doing something right. Trust comes in numbers.

Principle 2: Reciprocity

“Scratch my back and I’ll scratch yours.”

Ever wonder why restaurants provide breath mints together with the bill? Breath mints do not serve to just improve your breath, they help making sure you give a bigger tip.

When you receive something for free, people naturally feel the urge to pay back.

Principle 3: Scarcity

“A limited supply makes more desirable.”

Ever wonder why you get so much anxiety when booking a hotel on

After performing a simple search on, you are bombarded with following messages in search results:

  • Only 3 left on our site!
  • Latest booking: 5 minutes ago.
  • You’re too late! No rooms left at this property on our site.
  • Amsterdam is 85% unavailable for your dates on our site.

Feel stressed yet? All these messages signal scarcity. You need to book now because available rooms are limited and will run out soon. Fail to act and you will miss out on your precious booking.

Principle 4: Authority

“It is not titles that honor men, but men that honor titles.” — Machiavelli

The sender of a message matters. Fame, titles and awards convey credibility to what people have to say.

I love the writings of Seth Godin. Seth Godin is a famous marketing guru and considered an authority. Imagine I am at a book shop and take a random book off the shelf. I do not know the author. The front of the book prominently features the following quote:

“ Pirates bring choice and cause change. In this stunning book, Matt Mason forgets the parrots and the eye patches, but manages to teach us all a great deal. I learned a lot.” — Seth Godin

How do you think this quote affects my opinion about the book I just picked up?

Seth Godin’s praise passes on some of the credibility existing in my mind to the author of the book. Using such an approach is called influencing by authority. This is why brands pay big bucks for celebrity endorsements of their products. If Roger Federer loves a certain tennis racket, who are you to dislike it?

Principle 5: Commitment and Consistency

“I prefer to be true to myself, even at the hazard of incurring the ridicule of others, rather than to be false, and to incur my own abhorrence.”— Frederick Douglass

This principle combines two different natural tendencies people have:

  • People dislike saying no to very small and reasonable requests.
  • People want their current actions to be consistent with how they behaved in the past.

To apply this principle, you first ask for something small and reasonable. This will get your foot in the door. You just ask for something that requires little commitment and effort.

Later you follow-up with a bigger commitment that is up the same alley as the small commitment. Now people will be more likely to say yes to the bigger commitment, as they want to act consistent with their previous (small) commitment.

In a scientific experiment to research this principle, a researcher would visit different houses in a neighborhood. The researcher would ask inhabitants if it would be okay to place a giant sign in their garden that read “Drive Safe”.

Most people obviously said no. In another neighborhood, 76% of people said yes. What was the difference between the two areas?

In the second neighborhood, the researcher asked people to put a bumper sticker on their car that said “Drive Safe”. A few weeks later, the researcher came back to ask if it was okay to place a giant “Drive Safe” sign in their yard. Now most people said yes.

In the second neighborhood people started to identify with the sticker and received compliments from others. When the bigger request came around, there was a desire to be consistent with how they see themselves and how they had behaved before. So many of them they now said yes.

Principle 6: Liking

“Although Ronald Reagan was somebody I disagreed with on most ideological things, he was a friend of mine, and he was a very, very likable man.” — Warren Beatty

In Leiden, I regularly visited a cafe where I would have drinks together with friends. Just like every time when I visited, the bill came. Interestingly enough, this time the bill was different.

The waitress had written a nice message on the bill to thank us for having dinner and signed it with her name. She also threw in some peppermints together with the bill.

I asked her:”Did you recently get any training in persuasion principles, such as those of Cialdini perhaps?”. She blushed, as she knew that I knew. She was using these principles to get a bigger tip. She admitted the whole staff had received a training to apply these principles.

The handwritten note was added as a gesture so I would like her more. And hopefully give a bigger tip in return. Especially in combination with the peppermints.

When we like someone, we are more likely to go the extra mile for them. If they request something, we will do our best to help out. Who wouldn’t help Forrest Gump out? People are more easily persuaded by people that they like.

Cialdini’s principles of persuasion: what is known, cannot be unknown

Now that you know the six principles of persuasion, if you pay attention you will see them everywhere. In our ever busier and distracted lives, it is easy to rely on shortcuts to guide our thinking instead of actually thinking things through.

It is important to realize these shortcuts serve a purpose and our decisions may not be worse when we follow them. By being aware of these principles, you can choose to ignore them, if you notice somebody is using them to exploit you.

To recap, Cialdini’s six principles of persuasion are:

  1. Social proof. People enjoy the safety of following a path carved by others.
  2. Reciprocity. People have a natural tendency to pay back favors.
  3. Scarcity. When something is perceived as limited in supply, it will generate demand.
  4. Authority. Credentials, titles and fame convey credibility to people and make them more convincing.
  5. Commitment and consistency. People tend to act consistent with past commitments.
  6. Liking. When we like someone, we are more likely to be persuaded by them.