by Susan Cain
ISBN: 0307352153
Finished 3/10/16
Amazon page for details and reviews


In the United States, extroversion has become the ideal. But 1/3 to 1/2 of Americans are introverts, and these quiet, deliberate individuals are responsible for many of our social and technical achievements. Susan Cain’s work is less self-help and more of a framework for seeing the true value that introverts bring to the table. While introverts can train themselves to be more sociable, there is some biological basis for this behavioral trait that can never be overcome. And perhaps it would be better for extroverted leaders to sit back and listen, instead of maximizing air time.


Temperament is the most important part of personality. It is where we fall on the introvert-extrovert spectrum.

1/3 to 1/2 of Americans are introverts

We’ve turned extroversion into a standard

But introverts have created some of the things we value most

Some famous figures achieved results because of their introversion

Introverts tend to be thinkers

No all purpose definition of introversion vs extroversion

Introverts require less outside stimulation

They work more slowly and deliberately

Introverts prefer listening to talking. Even if they have strong social skills, they desire quiet and feel they can express themselves better in writing.

They enjoy deep discussions

Most introverts are not hermits and may not even be shy – can be very friendly

Bill Gates: non-shy introvert

Spectrum of introversion-extroversion, shy vs. nonshy

Ambivert: right in the middle between introvert and extrovert

Introverts more likely to be sensitive: 70% of sensitive people are introverts

Inferiority complexes are possessed by many introverts

The extrovert ideal

Dale Carnegie: introvert that started out learning about then teaching public speaking

We shifted from a culture of character to a culture of personality

Americans started shifting from rural into cities

Tony Robbins – personal development coach and life strategist

We tend to think extroversion makes us better people

Harvard Business School: the spiritual capital of extroversion

Many companies rely too heavily on presentation skills and not critical thinking skills

Many effective CEOs are introverts

Level 5 Leaders (Jim Collins) – extreme humility combined with intense professional will

Adam Grant (Give and Take) found limited correlation between extroversion and leadership
– Extroverted leaders work better with passive employees, while introverted leaders work better with those that are proactive

Introverts are more likely to hear and implement suggestions

Extroverted leaders may wish to become more reserved and listen to what people are saying

Rosa Parks – quiet but full of integrity and character

Connectors – Malcom Gladwell’s The Tipping Point
– People who know large numbers of others and are in the habit of making introductions
– Craig Newmark of Craigslist

Even Guy Kawasaki admitted to being introverted

Saddleback Evangelical Church – focused on personality. In evangelical churches, often extroversion is a prerequisite for leadership
– Socialability = godliness

Steve Wozniak: worked mostly alone at HP then built early Apple computers

More creative people tend to be socially poised introverts

The “new groupthink” insists teamwork and social skill is most important

Nearly all organizations build teams, but this phenomenon only blew up in the 1990s

70% of employees work in an open plan office

Cooperative or small group learning is incredibly common in early education

The internet brought gravitas to collaboration

But online and in-person interactions are fundamentally different

For musicians, chess players, college students, and sports players, deliberate practice alone is the best predictor of success

Top-performing programmers overwhelmingly worked for companies that gave them the most privacy, personal space, control over their physical environment, and freedom from interruption

Open plan offices impair productivity and memory. They are associated with high employee turnover and sickness. Also: hostility, insecurity, stress, high blood pressure, distraction, aggression.

Multitasking is a myth

37signals: remote workers and limited meetings. No-talk Thursdays. Prefers email and IM clients to in-person communication and interruption.

Personal space and freedom from peer pressure is vital to creativity

Rules of brainstorming (groups generate ideas in a non-judgmental atmosphere):
1. Don’t judge or criticize ideas
2. Be freewheeling. The wilder the idea the better
3. Go for quantity. The more ideas the better
4. Build on the ideas of fellow group members

But group brainstorming doesn’t actually work
– Performance gets worse as the group grows
– Only online brainstorming works well

Brainstorming does increase group attachment but not creativity

3 explanations for failure of group brainstorming
1. Social loafing: some sit back while others do the work
2. Production blocking: only 1 person can produce an idea at once
3. Evaluation apprehension: fear of looking stupid in front of one’s peers

High amounts of peer pressure and conformity in groups

But Woz worked with Jobs on Apple despite his introversion

Working in coffee shops: public-private interactions

The most effective teams are made of both introverts and extroverts

Success is a balance of alone and together time

Pixar bathrooms: single bathroom for each sex in front of building encouraged casual chance encounters

People can choose when to interact and when to be quiet

Population density is correlated with innovation. – Cities tend to be the areas of highest innovation.

Temperament: Inborn biologically-based behavioral and emotional patterns observable in infancy and early childhood

Personality: The complex brew that emerges after cultural influence and personal experience are thrown into the mix

Infant temperament and biomarkers can be linked to later personality. Due to the amygdala.

High reactivity is one biological basis for introversion

Blue eyes, hay fever, fair skin, and skinnier faces may also be linked with high reactivity. This may be ingrained in our social unconscious

Public speaking anxiety is more common than fear of death. This might be a primal human reaction: we run when predators have our eyes on us

Introverts are significantly more likely to fear public speaking

Introversion/extroversion is only about 50% heritable on average – there is some combination of genes and experience

Orchid hypothesis: Destinies of highly reactive children are most influenced by environmental factors, both positive and negative

Free will cannot allow us to go infinitely beyond genetic limitations: Bill Gates can never be Bill Clinton and vice-versa.

We cannot completely undo the effects of the amygdala: there will always be some biological basis for our personalities

Introverts are generally more sensitive to stimulation

It’s all about finding a stimulation sweet spot

Introverts function better when sleep-deprived

Introverts have a hard time speaking about things they aren’t convinced of

High reactive people feel what others feel

Eleanor Roosevelt: from shy young woman to lover of public life

Guilt is likely a building block of conscience

Functional, moderate guilt may promote future altruism, personal responsibility, adaptive behavior in school, and harmonious, pro-social relationships

The lower reactive you are, the cooler the temperature of your skin, the ‘cooler’ you are

Low heart rate is also associated with low reactivity

Blushing signifies concern for others

High reactivity is an evolutionary advantage
– Sensitivity shows the individual can discern subtle differences that lead to survival

Al Gore: one of the few introverts in politics

Sensitive people tend to speak softly because that’s how they prefer others to speak to them

Sensitive people enjoy small talk only after they’ve gone deep

Reward sensitivity can lead us to high status, but also outsize risks

Old brain (pleasure-seeking) is always in conflict with new brain (reason-seeking). But extroverts are more reward sensitive

Dopamine pathways appear to be more active in extroverts

Introverts are better at delaying gratification

Introverts are geared to inspect, extroverts to respond

When introverts make a mistake they slow down to analyze, but reward-sensitive extroverts actually speed up

When introverts notice their excitement, they slow down to analyze danger

Extroverts do better in grade school, introverts better in high school and college

In a state of flow, reward comes from within, and is found often in solitary pursuits

Warren Buffett divides the world into people who follow their own instincts and those who follow the herd

In Asian-American areas, introversion is a strength. Focus on school and intense tasks like chess
– The traditional East Asian curriculum emphasizes listening, and it is likely parents have carried this over for their children

Asians are more generally introverted than Europeans and Americans

What looks to a Westerner like subordination occurs to many Asians as politeness

In the West we subscribe to the extrovert ideal, while in much of Asia, silence is golden

Asians are not uncomfortable with who they are, but uncomfortable with expressing who they are

Asians may fall behind career-wise because they come across as passive

Soft power: quiet persistence. There is always substance even if it is not so effectively communicated

From the person-situation debate, we have learned our perceived personality can shift based on the situation we are in, but certain aspects remain fixed

Free trait theory: fixed and flexible traits coexist. Introverts or extroverts will do things out of character if they think the end goal is important

We can effectively fake it through self monitoring – acting based on social queues – but our true selves tend to seep out through behavioral leakage

Low self monitors can seem rigid and socially awkward. High self monitors can seem conformist and deceptive

HSMs have found to be better liars

Free trait agreement: we’ll act out of character some of the time so we can be in character the rest of the time

People who tend to suppress their emotions tend to have them leak later in more pronounced ways

Introverts and extroverts are attracted to one another but can clash

The need for intimacy is present in introverts and extroverts alike

Personality can be broken into 5 characteristics:
1. Introversion-extroversion
2. Agreeableness
3. Openness to experience
4. Conscientiousness
5. Emotional stability

Agreeableness was the biggest predictor for conflict-free relationships. Not correlated to extroversion

Introverts tend to avoid conflict while extroverts tend to deal with the issue upfront

Introverts like people they meet in a friendly manner while extroverts like people better when they are in conflict with them

Asians signal esteem by minimizing conflict while Israelies do not consider conflict a sign of disrespect, but a sign of concern

Venting doesn’t sooth anger, it fuels it

The very act of frowning triggers a negative emotional response. People with botox may be less angry

Participation vs. observation of social dynamics. Introverts are better at the latter

Iatrogenic treatment: diagnosing something that isn’t wrong

Even parents that have work to do on their own self esteem can be enormously helpful to children. They can show empathy and explain from experience

You can coerce children to act more sociably, but gently. It is mostly about observation and helping only when it seems appropriate

Introverts need a different type of early schooling than extroverts, and most primary schools are set up for extroverts

Person-environment fit: People flourish when they’re engaged in occupations, roles, and settings that are concordant with their personalities

The inverse is also true: kids stop learning when they feel emotionally threatened

When encouraging shy children to speak, it helps to make the subject compelling

Love is essential, gregariousness is optional