Influence Summary

1-Sentence-Summary: Influence has been the go-to book for marketers since its release in 1984, which delivers six key principles behind human influence and explains them with countless practical examples.

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Dr. Robert Cialdini needs no introduction. He is a legend in the world of marketing and sales. After three years of research at car dealerships, charity organizations, and telemarketing companies, he published this modern business classic in 1984.

Cialdini discovered 6 key principles which influence how we make decisions:

  1. Reciprocity
  2. Commitment/Consistency
  3. Social Proof
  4. Authority
  5. Liking
  6. Scarcity

Influence became a modern business classic. Just like The 7 Habits of Highly Effective People, it is now required reading for anyone trying to succeed in the world of work and entrepreneurship.

Cialdini calls his principles shortcuts: If they are triggered, we jump to conclusions faster. Our brains like using them because they save time. They can be used for us or against us, but it is essential to understand how they work.

Here are my favorite 3 of the 6 and how they work in action:

  1. You can use the reciprocity bias to build up a massive good karma account.
  2. The scarcity bias works, because we hate to miss opportunities.
  3. Make a small commitment to trigger your consistency bias and reach your goal.

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Lesson 1: You can use the reciprocity bias to build up a massive good karma account.

Imagine caveman Grok would have constantly been worried about his tasty beets. He’d never have shared any with Jane, the friendly cavewoman next door, because he didn’t see anything in it for him.

Subsequently, she would have never returned the favor with a late-night cave dinner and neither you, nor I, nor any of us would be here.

So why did Grok share his beets with Jane?


He knew that if he gave her food, she would owe him one.

Even though the reciprocity bias is one of the foundational reasons why we’re alive, today it’s often used against us.

We always feel compelled to return a favor, and marketers know this.

Not only that, we’ll usually return a much bigger favor than was made to us.

Consider this study from Cornell University in 1971, where researcher Joe brought some of the participants a 10 cent bottle of Coke (good times).

When asked to buy raffle tickets from Joe shortly afterwards, the people who “owed Joe one” bought 50 cents worth of tickets.

This is not only 5 times as much as the price of the Coke, but also twice as much money spent on tickets as in the scenarios where Joe didn’t bring people the Coke beforehand.

It’s the same trick the Hare Krishna’s have been using for decades by giving people flowers, and marketers often abuse it.

However, you can also flip this around.

Instead of trying to guilt people into reciprocity, why not just do good things without being asked to either way?

Go out of your way to help other people and you’ll naturally build up a massive good karma account. No tricks needed.

Lesson 2: Because we hate to miss opportunities, scarcity makes us act.

Don’t you hate missing out on a good deal? I know I’ve beaten myself up over a few Appsumo deals because I didn’t act fast enough.

The fact that you get so angry at yourself for not buying those jeans last week when they were on sale, or got that delicious pizza before they ran out for the day, is the reason why the scarcity bias works.

We beat ourselves up a lot for missing opportunities, regret is a powerful feeling.

People who were told of a limited time meat sale bought 3 times as much, even more when they learned that only they knew about the sale.

It makes me sad to see all this fake scarcity around the web now, where marketers peddle digital products with countdowns, limited edition labels and deadlines, as if they’re rare metals or oil.

So pay attention the next time you sign up for an email list and are offered a “2-day only” deal shortly afterwards. Unsubscribe and re-subscribe, and the loop starts all over again.

The scarcity bias is one of the most widely abused ones, so try to spot it wherever you can.

Lesson 3: When you make a small commitment, it triggers your consistency bias and helps you reach your goal.

Imagine you’re chilling on your towel at the beach, when suddenly, someone steals the radio of the person next to you, while they’re away.

What would you do?

If you’re honest, probably nothing, like 4 out of 5 people do.

Now imagine for a second that before leaving, your towel neighbor had asked you to watch her things.

Would you just let the thief get away? Most likely, you would at the very least say something.

In a study that tested this exact scenario, 95% of the people who committed to watching another person’s things even got up and chased down the thief.

A small commitment sure goes a long way, because it triggers your consistency bias.

This bias is very useful, because you can use it in your favor. For example, if you make a small commitment of not hitting the snooze button in the morning, you’ll really want to follow through.

Once you’re up, you can then use the extra time to develop an awesome morning routine.

Use mini commitments to jumpstart reaching your goals and then let the consistency bias take you the rest of the way. 

Influence Review

Whether you’re trying to avoid being influenced, looking for ways to trick yourself into building better habits or have a good message to spread across the world, Influence will help you get there.

Thanks to this summary alone, I’ve avoided many stupid purchases and built better relationships. It lists all the biases with examples, and is more than enough to get started.

I suggest you also watch this speed drawing video, which gives even more context.

I haven’t read the book myself, but it’s on the list, as I expect many more good examples, which will help remember all the biases.

Two big thumbs up!

Who would I recommend the Influence summary to?

The 15 year old high school student, who just discovered online shopping, the 43 year old manager, who struggles with getting his team at the office on the same page about things, and anyone who can’t seem to pick up a new habit.

Last Updated on July 27, 2022

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Niklas Göke

Niklas Göke is an author and writer whose work has attracted tens of millions of readers to date. He is also the founder and CEO of Four Minute Books, a collection of over 1,000 free book summaries teaching readers 3 valuable lessons in just 4 minutes each. Born and raised in Germany, Nik also holds a Bachelor’s Degree in Business Administration & Engineering from KIT Karlsruhe and a Master’s Degree in Management & Technology from the Technical University of Munich. He lives in Munich and enjoys a great slice of salami pizza almost as much as reading — or writing — the next book — or book summary, of course!