Do you enjoy having time to yourself, but always feel a little guilty about it? Then Susan Cain’s “Quiet : The Power of Introverts” is for you. It’s part book, part manifesto. We live in a nation that values its extroverts – the outgoing, the lovers of crowds – but not the quiet types who change the world. She recently answered questions from Mind Matters editor Gareth Cook.

Cook: This may be a stupid question, but how do you define an introvert? How can somebody tell whether they are truly introverted or extroverted?

Cain: Not a stupid question at all! Introverts prefer quiet, minimally stimulating environments, while extroverts need higher levels of stimulation to feel their best. Stimulation comes in all forms – social stimulation, but also lights, noise, and so on. Introverts even salivate more than extroverts do if you place a drop of lemon juice on their tongues! So an introvert is more likely to enjoy a quiet glass of wine with a close friend than a loud, raucous party full of strangers.

It’s also important to understand that introversion is different from shyness. Shyness is the fear of negative judgment, while introversion is simply the preference for less stimulation. Shyness is inherently uncomfortable; introversion is not. The traits do overlap, though psychologists debate to what degree.

Cook: You argue that our culture has an extroversion bias. Can you explain what you mean?

Cain: In our society, the ideal self is bold, gregarious, and comfortable in the spotlight. We like to think that we value individuality, but mostly we admire the type of individual who’s comfortable “putting himself out there.” Our schools, workplaces, and religious institutions are designed for extroverts. Introverts are to extroverts what American women were to men in the 1950s -- second-class citizens with gigantic amounts of untapped talent.

In my book, I travel the country – from a Tony Robbins seminar to Harvard Business School to Rick Warren’s powerful Saddleback Church – shining a light on the bias against introversion. One of the most poignant moments was when an evangelical pastor I met at Saddleback confided his shame that “God is not pleased” with him because he likes spending time alone.

Cook: How does this cultural inclination affect introverts?

Cain: Many introverts feel there’s something wrong with them, and try to pass as extroverts. But whenever you try to pass as something you’re not, you lose a part of yourself along the way. You especially lose a sense of how to spend your time. Introverts are constantly going to parties and such when they’d really prefer to be home reading, studying, inventing, meditating, designing, thinking, cooking…or any number of other quiet and worthwhile activities.

According to the latest research, one third to one half of us are introverts – that’s one out of every two or three people you know. But you’d never guess that, right? That’s because introverts learn from an early age to act like pretend-extroverts.

Cook: Is this just a problem for introverts, or do you feel it hurts the country as a whole?

Cain: It’s never a good idea to organize society in a way that depletes the energy of half the population. We discovered this with women decades ago, and now it’s time to realize it with introverts.

This also leads to a lot of wrongheaded notions that affect introverts and extroverts alike. Here’s just one example: Most schools and workplaces now organize workers and students into groups, believing that creativity and productivity comes from a gregarious place. This is nonsense, of course. From Darwin to Picasso to Dr. Seuss, our greatest thinkers have often worked in solitude, and in my book I examine lots of research on the pitfalls of groupwork.

Cook: Tell me more about these “pitfalls of groupwork.”

Cain: When you’re working in a group, it’s hard to know what you truly think. We’re such social animals that we instinctively mimic others’ opinions, often without realizing we’re doing it. And when we do disagree consciously, we pay a psychic price. The Emory University neuroscientist Gregory Berns found that people who dissent from group wisdom show heightened activation in the amygdala, a small organ in the brain associated with the sting of social rejection. Berns calls this the "pain of independence."

Take the example of brainstorming sessions, which have been wildly popular in corporate America since the 1950s, when they were pioneered by a charismatic ad executive named Alex Osborn. Forty years of research shows that brainstorming in groups is a terrible way to produce creative ideas. The organizational psychologist Adrian Furnham puts it pretty bluntly: The "evidence from science suggests that business people must be insane to use brainstorming groups. If you have talented and motivated people, they should be encouraged to work alone when creativity or efficiency is the highest priority."

This is not to say that we should abolish groupwork. But we should use it a lot more judiciously than we do today.

Cook: What are some of the other misconceptions about introverts and extroverts?

Cain: One big one is the notion that introverts can’t be good leaders. According to groundbreaking new research by Adam Grant, a management professor at Wharton, introverted leaders sometimes deliver better outcomes than extroverts do. Introverts are more likely to let talented employees run with their ideas, rather than trying to put their own stamp on things. And they tend to be motivated not by ego or a desire for the spotlight, but by dedication to their larger goal. The ranks of transformative leaders in history illustrate this: Gandhi, Eleanor Roosevelt, and Rosa Parks were all introverts, and so are many of today’s business leaders, from Douglas Conant of Campbell Soup to Larry Page at Google.

Cook: Is there any relationship between introversion and creativity?

Cain: Yes. An interesting line of research by the psychologists Mihaly Csikszentmihalyi and Gregory Feist suggests that the most creative people in many fields are usually introverts. This is probably because introverts are comfortable spending time alone, and solitude is a crucial (and underrated) ingredient for creativity.

Cook: Can you give some other examples of surprising introversion research?

Cain: The most surprising and fascinating thing I learned is that there are “introverts” and “extroverts” throughout the animal kingdom – all the way down to the level of fruit flies! Evolutionary biologist David Sloan Wilson speculates that the two types evolved to use very different survival strategies. Animal “introverts” stick to the sidelines and survive when predators come calling. Animal “extroverts” roam and explore, so they do better when food is scarce. The same is true (analogously speaking) of humans.

Cook: Are you an introvert?

Cain: Yes. People sometimes seem surprised when I say this, because I’m a pretty friendly person. This is one of the greatest misconceptions about introversion. We are not anti-social; we’re differently social. I can’t live without my family and close friends, but I also crave solitude. I feel incredibly lucky that my work as a writer affords me hours a day alone with my laptop. I also have a lot of other introvert characteristics, like thinking before I speak, disliking conflict, and concentrating easily.

Introversion has its annoying qualities, too, of course. For example, I’ve never given a speech without being terrified first, even though I’ve given many. (Some introverts are perfectly comfortable with public speaking, but stage fright afflicts us in disproportionate numbers.)

But I also believe that introversion is my greatest strength. I have such a strong inner life that I’m never bored and only occasionally lonely. No matter what mayhem is happening around me, I know I can always turn inward.

In our culture, snails are not considered valiant animals – we are constantly exhorting people to “come out of their shells” – but there’s a lot to be said for taking your home with you wherever you go.

Are you a scientist who specializes in neuroscience, cognitive science, or psychology? And have you read a recent peer-reviewed paper that you would like to write about? Please send suggestions to Mind Matters editor Gareth Cook, a Pulitzer prize-winning journalist at the Boston Globe. He can be reached at garethideas AT gmail.com or Twitter @garethideas.