Why do people say yes?

Why do people buy when they do?

Why are some people more popular than others?

Why are some products more valuable than others?

Why are some people treated differently than others?

These are all good questions for anyone interested in the world around them.

They are especially interesting for big corporations, marketers, and entrepreneurs trying to figure out how their customers think.

The answers to these questions are rooted in human psychology.

And therefore these principles can be used not only by marketers but any person who is interested in understanding the world around them.

Influence: The Psychology of Persuasion by Dr. Robert Cialdini is a brilliant book on the “Psychology of yes”.

Influence: The Psychology of Persuasion

The book goes into detail on this question: “Why do people say yes?”

Dr. Robert Cialdini explains persuasion with 6 main principles.

These principles will arm you with the skills to recognize when these principles are being used against you. 

And also as a valuable tool for you to use in everyday life.

So let's take a look at the 6 principles:

social proof

(1)Social Proof.

Humans have a natural sheep tenancy. 

That means if many people are doing something then it must be “good”.

That's why a lot of people who you consider to be “smart” sometimes do stupid things. 

They just follow the group.

This powerful principle is the reason why big companies pay celebrities to endorse their products. 

They know that even if it's a mediocre product the heard will follow the lead of the celebrity. 

I mean if the famous guy is doing it then it must be “good”.

This principle is even stronger when the people you are observing are similar to you. 

For example, if your coworkers or friends are doing something then that will have a strong influence on you to follow their lead because of the social proof of their actions. 

This principle goes back to our evolutionary past. 

A long time ago when we were still living in caves we watched others to make sure things are safe. 

For example, if one tribe watched another tribe swim across a crocodile-infested river then the other tribe would follow. 

Social proof…



This principle is very simple.

It simply states that we say yes to requests from people we like and know.

So the question is how do humans like each other in general? 


We tend to like people that we perceive to be similar to us.

People with the same education, background, financial status, political views, and achievements tend to be more “likable” for us.


The physical attractiveness of people plays a big role in how we react to them.

I mentioned the power of the Halo effect before on this blog and this liking principle has some similarities.

For example, a celebrity that is very attractive gets thousands of followers on Instagram because people want to be associated with the attractiveness of that person.


We tend to get comfortable and like people of groups we spend a lot of time with. 

Maybe you go to a certain restaurant every week and you tend to like everyone there.

In contrast to that, we tend to avoid the unknown and unfamiliar.

Most people don't like change.



This principle states that humans tend to give back when someone does something nice to them. 

For example, if I buy you a coffee you will tend to want to buy one back. 

This is even true towards people we don't even like.

A big way reciprocity is used is in sales.

For example, let's say someone wants to buy your house. 

To use this principle make a price that is a lot higher than what you actually want for the house. 

So let's say you think the house is worth 1 million dollars. 

Then set your price at 2 million. 

When the person tells you it's too much you tell them: “I will do you a favor and lower my price to 1.6 million”.

That person will then tend to want to return the “favor” of lowering the price and accept your offer of 1.6 million.

He thinks he's is winning, but it was actually you controlling the situation.

Another example of this could be used in relationships. 

You are planning a trip with your friends for a week.

You want to tell your wife/girlfriend you are going.

To get what you want tell your wife/girlfriend you want to go on a trip for 2 weeks. 

She says “No it's too long.”

Then you say “OK fine I will only go for a week”.

Then she is more likely to say yes.



This is a simple strategy that is abused by many governments and organizations around the world.

This principle states that we tend to listen to authority figures even in situations where their opinions make no logical sense. 

This principle is so strong that simple things like uniforms and titles are enough to make us think someone is a legitimate authority on something. 

That's why criminals will wear police uniforms to commit crimes.

That's is also why scam artists will put titles like MD or Ph.D. behind their names to use the “authority” to get to their objectives. 

This is a very powerful principle that is unfortunately abused by those in power.


(5)Commitment and Consistency.

When people make a decision about something they will tend to stay with that choice or opinion.

Even when that person is confronted with the truth and facts that disprove their decision they will tend not to change. 

In sales, this is sometimes used to push through a sale. 

For example, if you get someone to agree to buy a pair of shoes they will stick with that choice. 

Even if you tell them after the agreement that the shoes “are not waterproof” they will still buy it.

An example in relationships is a bad marriage. 

Many people stay in unhappy marriages because they made an earlier commitment.

Even when they find out their wife was cheating on them they don't get a divorce.



This is a powerful principle that is often used by companies to sell their products faster and at higher prices. 

This principle states that we humans perceive things to be of higher value when they are rare or becoming rare. 

Humans will be influenced by this principle when they have to work to get something or compete for something. 

This is another principle deeply rooted in our evolution as a species.

A long time ago we learned that some things that we needed would disappear if we didn't act quickly. 

For example, if the Salmon appeared in the river 1 day of the year and supply you with meat then the tribe would find this very valuable and scarce. 

The value of the salmon was high and perceived as a scarce resource.

Modern examples of this are:

“Today is the last day of the 50% Discount”

“Limited edition shoes”

Black Friday Sale

“Christmas Sale”

The Psychology of Persuasion


These are powerful principles and are tempting to use to expose people's weaknesses.

But a better idea is to use it to lead people to their noble side.

Use it as a tool where both parties win not just you.

Also, try to combine 2 or more principles for more powerful results. 

For example, combine scarcity and social proof. If a rare item is desired by a group of friends or co-workers it becomes even more valuable.

These principles can be used in your dating life, business, or family life. 

But use them wisely. 

With great power comes great responsibility.

Until next time.