Quiet: The Power of Introverts in a World That Can't Stop Talking by Susan Cain

Thursday, March 27, 2025

Fascinating deep dive into the world of introversion and extroversion. Some meaningful parts of our temperament are genetic and passed down from our parents. If you’re a fussy, highly sensitive baby at four months, there’s a good chance you’ll grow up to be introverted. There seems to be a biological connection between high physical sensitivity and introversion.

Highly sensitive people also process information about their environments—both physical and emotional—unusually deeply. They tend to notice subtleties that others miss—another person’s shift in mood, say, or a lightbulb burning a touch too brightly.

According to Cain, bloggers are almost always introverts. We’ll share personal details with an online multitude they would never disclose at a cocktail party. This is me.

The U.S. is one of the most extroverted countries in the world, while countries in Asia rank among the most introverted. The difference relates in part to genetics but mostly to cultural norms.

Social anxiety disorder in Japan, known as taijin kyofusho, takes the form not of excessive worry about embarrassing oneself, as it does in the United States, but of embarrassing others.

Best takeaway: An introverted/extroverted couple likely has a conflict in their degree of shared sociability. Cain recommends a “Free Trait Agreement” where each partner agrees to a balance of activities in their free time, i.e., a wife who wants to go out every Saturday night and a husband who wants to relax by the firework out a schedule: half the time they’ll go out, and half the time they’ll stay home. Helpful for this INTJ.

Highlights

I am a horse for a single harness, not cut out for tandem or teamwork … for well I know that in order to attain any definite goal, it is imperative that one person do the thinking and the commanding. —ALBERT EINSTEIN

Newton was one of the world’s great introverts. William Wordsworth described him as “A mind forever / Voyaging through strange seas of Thought alone.”

Some people are more certain of everything than I am of anything. —Robert Rubin, In an Uncertain World

Psychologists often discuss the difference between “temperament” and “personality.” Temperament refers to inborn, biologically based behavioral and emotional patterns that are observable in infancy and early childhood; personality is the complex brew that emerges after cultural influence and personal experience are thrown into the mix.

High reactivity is one biological basis of introversion … Results have consistently suggested that introversion and extroversion, like other major personality traits such as agreeableness and conscientiousness, are about 40 to 50 percent heritable … the footprint of a high- or low-reactive temperament never disappeared in adulthood.

High-reactive men are more likely than others to have a thin body and narrow face.

high-reactive children may be more likely to develop into artists and writers and scientists and thinkers because their aversion to novelty causes them to spend time inside the familiar—and intellectually fertile—environment of their own heads.

Sometimes speakers need to talk about subjects that don’t interest them much, especially at work. I believe this is harder for introverts, who have trouble projecting artificial enthusiasm.

There is no one more courageous than the person who speaks with the courage of his convictions.

Highly sensitive people also process information about their environments—both physical and emotional—unusually deeply. They tend to notice subtleties that others miss—another person’s shift in mood, say, or a lightbulb burning a touch too brightly.

Sensitive types think in an unusually complex fashion. It may also help explain why they’re so bored by small talk.

Some scientists are starting to explore the idea that reward-sensitivity is not only an interesting feature of extroversion; it is what makes an extrovert an extrovert. Extroverts, in other words, are characterized by their tendency to seek rewards, from top dog status to sexual highs to cold cash.

Introverts and extroverts also direct their attention differently: if you leave them to their own devices, the introverts tend to sit around wondering about things, imagining things, recalling events from their past, and making plans for the future. The extroverts are more likely to focus on what’s happening around them. It’s as if extroverts are seeing “what is” while their introverted peers are asking “what if.”

Introverts need to trust their gut and share their ideas as powerfully as they can. This does not mean aping extroverts; ideas can be shared quietly, they can be communicated in writing, they can be packaged into highly produced lectures, they can be advanced by allies. The trick for introverts is to honor their own styles instead of allowing themselves to be swept up by prevailing norms.

Social anxiety disorder in Japan, known as taijin kyofusho, takes the form not of excessive worry about embarrassing oneself, as it does in the United States, but of embarrassing others.

Taking shelter in bathrooms is a surprisingly common phenomenon, as you probably know if you’re an introvert.

According to Free Trait Theory, we are born and culturally endowed with certain personality traits—introversion, for example—but we can and do act out of character in the service of “core personal projects.” In other words, introverts are capable of acting like extroverts for the sake of work they consider important, people they love, or anything they value highly.

Pay attention to what you envy. Jealousy is an ugly emotion, but it tells the truth. You mostly envy those who have what you desire.

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