Quiet: Book Summary & Review

susan cain quiet book cover

In Quiet: The Power of Introverts author Susan Cain explains what it means to be an introvert, what are the advantages and disadvantages, and how society can win by getting the most out of both introverts and extroverts.

Bullet Summary

  • Introverts are better at analyzing and learning from mistakes
  • You can learn to be more extrovert
  • Introverts are generally more sensitive to stimuli and threats, are more sensitive and get overwhelmed more easily
  • It’s not true that extroverts are more socially skilled

Full Summary

About The Author: Susan Cain does not actually have a background in psychology or people-related fields. She studied law and she is a writer and lecturer.
However, she did a good job here with some thorough research.

Western Society Favors Extroverts

Susan Cain says that Western society has an extrovert bias and that extroverts’ traits are more likely to lead to personal and career success.

She mentions Tony Robbins as an example that our culture equates high-powered extroversion -and borderline narcissism– and as the pinnacle of leadership.

Harvard business school is also structured to make students more outspoken and extroverted.
And organizations emphasize team works, bosses want “interpersonal skills”, and the entrepreneurs who get VC money have confident or overconfident personalities.

Even the authors who get published must convince publishers that they are “talk show ready”.
Susan Cain says you wouldn’t be reading to Quiet if she hadn’t convinced her publisher.

And many introverts grow up believing “there must be something wrong with them”.

Quiet: The Power of Introverts challenges all of that.

Are You Introvert or Extrovert?

Susan Cain says there is no standard description for introversion, but she gives a helpful list.


  • Are drawn to their inner world of thoughts and feelings;
  • Focus on the meaning of events;
  • Recharge batteries with lone time;
  • Feel good with little stimulation (ie.: quietly sipping wine);
  • Prefer one task at a time and can focus;
  • Are more immune to social status;
  • Listen more, dislike conflict, and think before they speak
  • Process information more deeply (think and ponder deeply)
  • Pay more attention to warning signals
  • Have more “muted” reactions to stimuli


  • Are drawn to the external life of people and activities
  • Plunge in the events around them
  • Need to recharge with socialization
  • Prefer multitasking and jumping from one thing to another
  • Are more risk-taking
  • Tend to be more assertive, and dominant, speak more than talk, and are comfortable with conflict
  • React more quickly
  • Pay more attention to the reward (and can make mistakes rushing and taking risks)
  • Amplify positive emotions (which can lead more easily to addictions though)
  • Cheat more, exercise more, have more sex partners, and divorce more frequently

Quiet’s Introversion Quiz

  1. I prefer one-on-one conversations to group activities.
  2. I often prefer to express myself in writing.
  3. I enjoy solitude.
  4. I seem to care about wealth, fame, and status less than my peers.
  5. I dislike small talk, but I enjoy talking in-depth about topics that matter to me.
  6. People tell me that I’m a good listener.
  7. I’m not a big risk-taker.
  8. I enjoy work that allows me to “dive in” with few interruptions.
  9. I like to celebrate birthdays on a small scale, with only one or two close friends or family members.
  10. People describe me as “soft-spoken” or “mellow.”
  11. I prefer not to show or discuss my work with others until it’s finished.
  12. I dislike conflict.
  13. I do my best work on my own.
  14. I tend to think before I speak.
  15. I feel drained after being out and about, even if I’ve enjoyed myself.
  16. I often let calls go through to voice mail.
  17. If I had to choose, I’d prefer a weekend with absolutely nothing to do to one with things too many scheduled.
  18. I don’t enjoy multi-tasking.
  19. I can concentrate easily.
  20. In classroom situations, I prefer lectures to seminars.

The more yeses you give, the more introverted you are.
If you are split around the middle, then you might be an ambivert.

Susan Cain says there are no 100% pure introverts or extroverts.

And even if you are very introverted or very extroverted, that is not a predictor of your behavior in each situation.
It would be like saying that all men like contact sports. A lot of men do, but not everyone.

Shyness VS Introversion

People often confuse shyness with introversion.
And that makes sense actually, because the two can look similar and overlap.

Susan Cain says that shyness is the fear of social disapproval and humiliation, while introversion is the preference for an environment that is not overstimulating.
Shyness is painful for the shy individual, while introversion is not.

You can confuse them easily because the external behavior may look the same.
The shy person in the business meeting does not speak because he’s afraid of speaking up. The introvert does not speak because he is observing, and processing data and information in his head.
But to the external observer, the two look very similar.

Brain Differences: High & Low Reactivity

Introverts have a more sensitive amygdala than extroverts.

The amygdala helps us detect changes in the environment, especially threats, and dangers.

Introverts are naturally more highly alert to changes (high reactivity), which makes them more prone to the release of cortisol and stress.

That makes introverts more reactive and sensitive in general.
Indeed, following this train of thought, it’s not just that introverts get more easily flooded during social interactions: they are more easily flooded in any new environment.

Seeking or Avoiding Stimuli

Introverts prefer less stimulation. Fewer people, lower volume music, and a quieter, less chaotic environment -and less coffee, too-.
Extroverts, are the opposite.

An experiment showed indeed that introverts perform better with a lower level of noise while extroverts perform better with higher levels of noise.
Introverts also perform better when sleep deprived because sleep deprivation makes us less alert.

Nature or Nurture?

Introversion and extroversion, like all other major personality traits like agreeableness and conscientiousness, are about 40-50% heritable.

What about the other half?
Well, one theory is that when you are born with a certain tendency, you tend to seek out experiences that push you further along your natural tendency.

Risks & Opportunities of Nurture

So low reactive, extrovert children, climb more trees, jump more fences, and naturally grow more comfortable with the challenges and fears around them.

The risk if they grow up in a bad neighborhood is that they are more likely to end up in gang crime.
If they grow up in good families that channel them, say the author, they are more likely to become driven overachievers (Oprah and Richard Branson).
Taking it to an extreme, sociopaths have an extremely low level of reactivity. Lykken has controversially called psychopaths and heroes “twigs on the same genetic branch”.
Also, read:

The risk for introvert children is that they have too little experience and grow up too afraid.
And they are more sensitive to both good and bad environments around them. If that’s the case, they are more likely to slip into depression, anxiety, and social anxiety.
The upshot is that introverted kids also enjoy a bigger boost from stable home environments and good parenting. If they get such positive nurturing, they tend to have fewer emotional problems and more social skills.

Introverts Learn Better Than Extroverts

A study shows that introverts tend to make fewer mistakes because they are less impulsive and think more.

But the most interesting aspect is what happens after the mistake.
After the mistake introverts slow down.
Extroverts instead speed up. And don’t learn as much from their mistakes.

Reward and Treat Orientation

This is because extroverts seek the win and the buzz and don’t focus on the threats.
Any roadblock along the way is something they want to smash as quickly as possible.

Introverts instead are programmed to analyze the environment and look for threats and pitfalls.

Changing Our Personalities

We can certainly change our personalities.

But up to a certain point (rubber band theory).
For example, when we engage in positive self talk the amount of activity in our amygdala goes down and activity in the prefrontal cortex goes up.

But it’s not powerful enough to switch off the amygdala altogether. The unlearning indeed is not total.
The prefrontal cortex can suppress the amygdala, but during times of stress, when the prefrontal cortex is too weak to soothe the amygdala, the fears can resurface again.

Self Monitoring

Introverts who were better at learning to act as extroverts score very high at a trait that psychology calls “self-monitoring”.

Self-monitors are very good at scanning social environments and looking for social cues. Then they are very able to act and behave in ways that conform to the environment.

These are the ultimate social chameleons.

Introversion and Sensitivity

Introverts are more likely to be highly sensitive and to have a strong conscience.
They are more likely to be moved by a serenade or a kind act.

We don’t know exactly how many introverts are also sensitive, but we do know that 70% of sensitive people are introverts. And even the other 30% need a lot of “downtime”.

This seems to say that there is an overlap between introvert qualities and sensitivity.

Also, read:

Introverts Understand Social Dynamics Better

A study showed that extroverts were better at gauging whether their conversation partner was glad to be talking to them.

And that seemed to confirm the obvious: extroverts are better at social skills.

But that was because the study measured the understanding while the conversation happened, and extroverts are better at multitasking.

When it comes to observation, studies showed either no difference or that introverts were better at picking social cues.

Communication Style

Introverts tend to be conflict-avoiders while extroverts easily engage in conflict and speak more directly.

Extroverts tend to talk about lots of topics, while introverts pick a few and dig deeper into them.

But the funny thing is that they can get along very well with each other.
Introverts feel extroverts are a breath of fresh air, while extroverts feel they can relax with introverts.

Agreeableness and Intimacy

Introversion is not correlated with agreeableness and enjoyment of intimacy.

Introverts are just as likely to search for the company of others. Just in smaller doses.

Introversion and Extroversion in Leadership

We all have a tendency to equate charisma and extroversion with competence.
And to follow the more outspoken leader, the one who seems to have a quick answer to problems.

But we are wrong:

Why The Super Extrovert Leader Myth is Wrong

The more extroverted and charismatic leaders have higher salaries, but not better performances.
Jim Collins research set out to study what made corporations outperform the market and didn’t want to touch upon leadership.
However, it turned out that leadership was instrumental to outperformance.
And the best leaders, as exemplified by Adam Smith, were all unassuming, quiet, reserved, and mild-mannered. Some people even described them as shy.

Basically, the myth of the highly extroverted charismatic leader as the effective man at the helm of the organization does not hold true in the research.

Susan Cain says:

We need leaders who build not their egos, but the institutions they run.

Now the question: are introverts better leaders?

Introverts Are Better Leaders of Great Workforces

Extroverts manage to get higher performances when their teams are passive and do their job without exercising initiative.

Introverts outperform extrovert leaders when they are heading a motivated and active workforce.

What’s the difference?
Introverts listen to the inputs from their team and are more likely to empower them and put those ideas to the test.

This research is still in its infancy, says the author, but it’s highly promising.

Introverts Underrated Powers

  • Alertness
  • Sensitivity to nuances
  • Complex emotionality
  • Power of focus over the long haul (grit)
  • Deeper analysis of topics
  • Better at delaying gratification (a staple of long-term success)
  • Learn better from mistakes (are more reflective and less likely to rush through)
  • Less likely to get caught up in “deal fever” and “winner’s curse” (ie.: competitive mistakes)
  • Better control their emotions (best traders tend to be emotionally stable introverts)
  • See the dangers (not by chance the men who foresaw the financial crisis were outcasts not duped by groupthink)
  • Less drawn to easy rewards like the lures of alcohol, sex, party, and drugs (don’t buzz as easily)
  • Accuracy over speed

Alone Practice is Best Predictor of Success

Susan Cain links to the research in The Talent Code and deep practice.

She says that practicing in groups is not the best and most effective way of doing deep practice because it requires unwavering, direct, and undisturbed focus.
It also requires working hard on the parts that are most challenging to you.
In most disciplines, that happens when practicing alone.

That’s a big advantage for introverts, who naturally prefer alone time to work.

Good Ideas Drown In Extroverts/Introverts Mixed Groups

Let’s imagine that extroverts have equally good ideas as introverts -and that might be an understatement!-.

The simple way how extroverts and introverts communicate will almost guarantee that great ideas from introverts will drown out.

Extroverts tend to think out loud and speak up. Introverts tend to be soft-spoken and to think through their ideas longer.
This means that extroverts’ ideas and opinions will get more air time and that extroverts’ ideas and points of view will often not be heard at all.

The issue is compounded by our tendency to rate talkers as smarter than quiet ones (while studies show the opposite).

Studies show that is exactly what happens.
Studies show that we are wasting introverts’ good ideas!

What to do then?

Brain Storming Doesn’t Work: Here’s What to Do

Brainstorming happens in groups and has four pillars:

  • Generate as many ideas as possible
  • Don’t judge or criticize ideas
  • Be freewheeling, don’t censor your ideas
  • Build on the ideas of fellow group members

But here is what research shows:

  • People produce more ideas when they are alone
  • The ideas they produce alone are of higher quality
  • Performance gets worst as the group size increases (unless it’s online groups)
  • Groups alter people’s minds in a way that promotes groupthink and conformity (and people actually believe they reached the conclusion on their own and without pressure)

What’s the solution then?

If you have talented team members encourage people to work alone when you are looking for creativity and efficiency

  • Make people come up with ideas before the meeting
  • Encourage electronic collaboration

Internet Empowers Introverts

Malcolm Gladwell’s The Tipping Point popularizes the idea of connectors as super extroverts with hundreds of friends and connections.

But building a huge following is not a prerogative of extroverts anymore.

Today an introvert can start a website, a blog, a digital product, or even self-publish a book.

The Internet changed the rules.
The same person who finds it difficult to introduce himself at a bar can gather millions of followers online.

Real-Life Applications

Exaggerate When You Pitch Extroverts (and Politicians)
Politicians tend to be extroverts. If you need to pitch a congress, make your pitch more attention than you normally would because extroverts have a higher bar when it comes to sensitivity and you need more stimuli to get through.

Include Introverts In Your Organization
Keep in mind around one-third of your team is introverted.
Give them space in open offices, and allow your team to write down their ideas. And watch out for groupthink and for losing the introverts’ best ideas to the louder extroverts.

Leverage Your Strengths
Whichever you lean towards, learn what are your strengths and play by them.
If the system is skewed toward open offices for extroverts, then don’t play by the system’s rules.


Some Off Topics
We didn’t need to hear about Tony Robbins seminars in my opinion. A bit of it also felt like a couched attack on Tony Robbins.
I thought that part was irrelevant and way too long for the value it added.

Missed One Citation
Quiet is awesome and well-researched. At a certain point, the author said “introversion is a better predictor of grades than cognitive abilities”.
That seemed huge to me and I wish she had given a reference for such a statement.


Helps You Understand People
If you have been reading around here for a while you know that I rarely give out five stars.
But as a man passionate about understanding people, Quiet has opened new doors of understanding for me.

Best Resource for Introverts and Extroverts
If you want to better understand introversion and extroversion, look no further.

Can Be Life Changing
For people who are struggling as introverts in a world designed for extroverts, they can actually face nasty psychological consequences. They can think they are not good enough for not coping well with open offices and multitasking.
For these people, Susan Cain’s Quiet can be a life changer.

Quiet Review

I approached this book thinking I already knew about introversion and extroversion.
I thought Susan Cain’s Quiet was going to confirm a couple of things and add one or two more.

I am glad I was terribly wrong: Quiet changed the way I understand introversion and extroversion.

And it deeply expanded my knowledge of psychology and people.

Including my own self-awareness.
Susan Cain says that introverts process and ponder more deeply. And introverts who are socially oriented spend a lot of time thinking about social dynamics and social interactions.
This is why I became good at analyzing social interactions and power dynamics.

This is a great read for those who want to understand people and psychology.
But it’s also an important book from a leadership, organizational, and business point of view to get the most out of the many introverts in the workforce.

Check out the best psychology books or get the book on Amazon

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