People who got to know my from my blog are usually surprised when they meet me in person.
I like to write, but I am not very talkative. I try to avoid group activities. I don't like to draw attention to myself, and I don't like crowds. I'm noise-sensitive. I prefer reading over parties, and if you find me at a party, I'm the one in the corner watching the others. My school memory contains a long series of teachers telling me to speak up more often. My Myers Briggs type is INTJ, with 100% on the introvert scale.
I am, in short, the sort of person that Susan Cain's book is about. So how could I not read it.
Susan Cain, a self-confessed introvert herself, has collected results of scientific studies on introversion and extroversion, from neurology, psychology and sociology. As it has recently been the case with many personality traits, evidence is building up that they are to some extend genetic, but the strength of expression also depends on environmental influences. This also means that while we can't change our genetic predisposition, we have some flexibility to deal with it.
Cain writes studies show that one third to one half (depending on the study) of all adults in North America are introverts, yet the American culture has glorified the extrovert ideal. That is, so Cain argues, a disadvantage not only for the introverts, many of whom end up pretending to be something they're not, but also for society as a whole because we're not making good use of many skilled people. Cain discusses studies that have shown that in the right circumstances, thinking brings better results alone than in groups, and that some leadership roles call for extroverts, and some for introverts. Extroverts do better, it turns out, when motivating others is relevant. Introverts do better when listening is important.
"[E]xtrovert leaders enhance group performance when employees are passive, but... introvert leaders are more effective with proactive employees."
She covers a lot of ground in her book, and draws upon many examples, Rosa Parks, Gandhi, Eleanor Roosevelt and Moses, just to mention a few.
"We don't ask why God chose as his prophet [Moses,] a stutterer with a public speaking phobia. But we should. The book of Exodus is short on explication, but its stories suggest that introversion plays the yin to the yang of extroversion."
In her book, Cain discusses for example evidence from Jerome Kagan's research that shows introversion is linked to a physiological trait called "high reactivity." I used to say I have an input filter problem. Amazingly enough, it turns out that's pretty much exactly what Kagan's research, and the research of those who have followed up on his original intuition, has shown. "High reactivity" is a higher activity in a brain region called the amygdala when confronted with something new. Infants who show high reactivity are more likely to grow up to be introverted adults; they need less stimulation than extroverts.
Later in the book, Cain also discusses another trait called "reward sensitivity," basically how active the brain's reward circuit is, and how much attention we thus pay to prospects of rewards:
"[E]xtroverts seem to be more susceptible than introverts to the reward-seeking cravings of the [limbic system of the brain]. In fact, 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."
Cains book is very carefully written. She points out repeatedly that no two people are alike and the reader might not feel well classified in all terms she discusses. Introversion is for example correlated with agreeableness and conflict aversion. As you might have guessed, I'm not a very agreeable person ;o) Cain also explains that it's not uncommon for people to "act out of character" if the situation calls for it, but too much of it can lead to a burnout. Professor Brian Little calls it the "Free Trait Theory":
"Introverts are capable of acting like extroverts for the sake of work they consider important, people they love, or anything they value highly."
That would be me organizing a conference.
Cain's argument is also very balanced. Her perspective is that there's not one best way of doing things, but that introverts and extroverts both bring different strengths that we are not all presently supporting and using very well. She seems to have taken particular offense in teachers using group tables, something I too recall very well from my schooldays. She argues for seeking a better way to do things, based on recent insights about how differently people's brains work
"We should actively seek out symbiotic introvert-extrovert relationships, in which leadership and other tasks are divided according to people's natural strengths and temperaments. The most effective teams are composed of a healthy mix of introverts and extroverts, studies show, and so are many leadership structures."
Cain is also careful to point out that extroversion and introversion are partly cultural, and she discusses to some extend the tension of Asian-Americans. She doesn't go into the cultural aspects very much though. I guess it's not very well understood.
The book is well referenced, she does mention if a research result is still under discussion or maybe even controversial. She doesn't merely report, but also brings in her own opinion. The book is flawlessly written. For the first two of three parts I found it to be the best non-fiction book I've read lately. It taught me a lot of things I hadn't previously known, without drowning me in irrelevant details. Then I came to the last part of the book.
The last part of the book gives the reader advice how to manage their personal lives and relationships. It's about the couples Greg and Emily, and John and Jennifer. It's about Joyce and her daughter Isabel, and about Sarah and her daughter Ava. I would have much preferred Susan Cain's book without the self-help part. Not only because I'm happily married to another introvert and wasn't looking for advice, but because for 200 pages I was thinking to send a copy of her book to some of my extrovert friends, just so they understand. Now I'd risk they think I'm suggesting they need help with their marriage or parenting.
In summary: If you are, as I, following research in neurology and psychology only peripherally, Susan Cain's book is likely to teach you something about yourself, and your friends and relatives. It is a well written, well researched, and well argued book that studies both the powers and weaknesses of introversion and extroversion, and addresses the question how much of these personality traits are nature and how much nurture. I would recommend this book to everybody who has ever felt they have trouble understanding others or themselves.
You can read an excerpt of Susan Cain's book here, and you can watch her TED talk here.