For inspiration that I would bottle and sell if I could, I thank the owners of the cottage in Amagansett: Alison (Sunny) Warriner and Jeanne Mclemore. The same goes for Evelyn and Michael Polesny, proprietors of the magical Doma Cafe in Greenwich Village, where I wrote most of this book.

Thanks also to those who helped with various aspects of getting Quiet off the ground: Nancy Ancowitz, Mark Colodny, Bill Cunningham, Ben Dattner, Aaron Fedor, Boris Fishman, David Gallo, Christopher Glazek, Suzy Hansen, Jayme Johnson, Jennifer Kahweiler, David Lavin, Ko-Shin Mandell, Andres Richner, JillEllyn Riley, Gretchen Rubin, Gregory Samanez-Larkin, Stephen Schueller, Sree Sreenivasan, Robert Stelmack, Linda Stone, John Thompson, Charles Yao, Helen Wan, Georgia Weinberg, and Naomi Wolf.

I owe a special debt to the people I wrote about or quoted, some of whom have become friends: Michel Anteby, Jay Belsky, Jon Berghoff, Wayne Cascio, Hung Wei Chien, Boykin Curry, Tom DeMarco, Richard Depue, Dr. Janice Dorn, Anders Ericsson, Jason Fried, Francesca Gino, Adam Grant, William Graziano, Stephen Harvill, David Hofmann, Richard Howard, Jadzia Jagiellowicz, Roger Johnson, Jerry Kagan, Guy Kawasaki, Camelia Kuhnen, Tiffany Liao, Richard Lippa, Joanna Lipper, Adam McHugh, Mike Mika, Emily Miller, Jerry Miller, Quinn Mills, Purvi Modi, Joseph Newman, Preston Ni, Carl Schwartz, Dave Smith, Mark Snyder, Jacqueline Strickland, Avril Thorne, David Weiss, Mike Wei, and Shoya Zichy.

There are many, many others who aren't mentioned by name in Quiet but who gave generously of their time and wisdom, via interviews and the like, and who dramatically informed my thinking: Marco Acevedo, Anna Allanbrook, Andrew Ayre, Dawn Rivers Baker, Susan Blew, Jonathan Cheek, Jeremy Chua, Dave Coleman, Ben Dattner, Matthew Davis, Scott Derue, Carl Elliott, Brad Feld, Kurt Fischer, Alex Forbes, Donna Genyk, Carole Grand, Stephen Gerras, Lenny Gucciardi, Anne Harrington, Naomi Karten, James McElroy, Richard McNally, Greg Oldham, Christopher Peterson, Lise Quintana, Lena Roy, Chris Scherpenseel, Hersh Shefrin, Nancy Snidman, Sandy Tinkler, Virginia Vitzthum, E. O. Wilson, David Winter, and Patti Wollman. Thank you, all.

Most of all I thank my family: Lawrence and Gail Horowitz, Barbara Schnipper, and Mitch.e.l.l Horowitz, whom I wrote about in the dedication; Lois, Murray, and Steve Schnipper, who make the world a warmer place; Steve and Gina Cain, my wonderful West Coast siblings; and the inimitable Heidi Postlewait.

Special thanks and love to Al and Bobbi Cain, who lent me their advice, contacts, and professional counsel as I researched and wrote, and who constantly cause me to hope that one day I will be as devoted and supportive an in-law to some young person as they are to me.

And to my beloved Gonzo (a.k.a. Ken), who may just be the most generous person on earth, and the most dashing. During the years I wrote this book, he edited my drafts, sharpened my ideas, made me tea, made me laugh, brought me chocolate, seeded our garden, turned his world upside down so I had time to write, kept our lives colorful and exciting, and got us the h.e.l.l out of the Berkshires. He also, of course, gave us Sammy and Elishku, who have filled our house with trucks and our hearts with love.

Notes

INTRODUCTION: THE NORTH AND SOUTH OF TEMPERAMENT

1. Montgomery, Alabama. December 1, 1955: For an excellent biography of Rosa Parks, see Douglas Brinkley, Rosa Parks: A Life (New York: Penguin, 2000). Most of the material in Quiet about Parks is drawn from this work.

A note about Parks: Some have questioned the singularity of her actions, pointing out that she'd had plenty of civil rights training before boarding that bus. While this is true, there's no evidence, according to Brinkley, that Parks acted in a premeditated manner that evening, or even as an activist; she was simply being herself. More important for Quiet's purposes, her personality did not prevent her from being powerful; on the contrary, it made her a natural at nonviolent resistance.

2. "north and south of temperament": Winifred Gallagher (quoting J. D. Higley), "How We Become What We Are," The Atlantic Monthly, September 1994. (Higley was talking about boldness and inhibition, not extroversion and introversion per se, but the concepts overlap in many ways.)

3. governs how likely we are to exercise: Robert M. Stelmack, "On Personality and Arousal: A Historical Perspective on Eysenck and Zuckerman," in Marvin Zuckerman and Robert M. Stelmack, eds., On the Psychobiology of Personality: Essays in Honor of Marvin Zuckerman (San Diego: Elsevier, 2004), 22. See also Caroline Davis et al., "Motivations to Exercise as a Function of Personality Characteristics, Age, and Gender," Personality and Individual Differences 19, no. 2 (1995): 16574.

4. commit adultery: Daniel Nettle, Personality: What Makes You the Way You Are (New York: Oxford University Press, 2007), p. 100. See also David P. Schmitt, "The Big Five Related to Risky s.e.xual Behaviour Across 10 World Regions: Differential Personality a.s.sociations of s.e.xual Promiscuity and Relationship Infidelity," European Journal of Personality 18, no. 4 (2004): 30119.

5. function well without sleep: William D. S. Killgore et al., "The Trait of Introversion-Extraversion Predicts Vulnerability to Sleep Deprivation," Journal of Sleep Research 16, no. 4 (2007): 35463. See also Daniel Taylor and Robert M. McFatter, "Cognitive Performance After Sleep Deprivation: Does Personality Make a Difference?" Personality and Individual Differences 34, no. 7 (2003): 117993; and Andrew Smith and Andrea Maben, "Effects of Sleep Deprivation, Lunch, and Personality on Performance, Mood, and Cardiovascular Function," Physiology and Behavior 54, no. 5 (1993): 96772.

6. learn from our mistakes: See chapter 7.

7. place big bets in the stock market: See chapter 7.

8. be a good leader: See chapter 2.

9. and ask "what if": See chapters 3 and 7.

10. exhaustively researched subjects: As of May 2, 2010, in the PSYCINFO database, there were 9,194 entries on "extraversion," 6,111 on "introversion," and 12,494 on the overlapping subject of "neuroticism." There were fewer entries for the other "Big 5" personality traits: openness to experience, conscientiousness, and agreeableness. Similarly, as of June 14, 2010, a Google scholar search found about 64,700 articles on "extraversion," 30,600 on "extroversion," 55,900 on "introversion," and 53,300 on "neuroticism." The psychologist William Graziano, in an e-mail dated July 31, 2010, refers to introversion/extroversion as "the 300 lb. gorilla of personality, meaning that it is big and cannot be ignored easily."

11. in the Bible: See "A Note on Terminology."

12. some evolutionary psychologists: See chapter 6.

13. one third to one half of Americans are introverts: Rowan Bayne, in The Myers-Briggs Type Indicator: A Critical Review and Practical Guide (London: Chapman and Hall, 1995), 47, finds the incidence of introversion at 36 percent, which is in turn determined from Isabel Myers's own study from 1985. A more recent study, published by the Center for Applications of Psychological Type Research Services in 1996, sampled 914,219 people and found that 49.3 percent were extroverts and 50.7 percent were introverts. See "Estimated Frequencies of the Types in the United States Population," a brochure published by the Center for Application of Psychological Type (CAPT) in 1996 and 2003. That the percentage of introverts found by these studies rose from 36 percent to 50.7 percent doesn't necessarily mean that there are now more introverts in the United States, according to CAPT. It may be "simply a reflection of the populations sampled and included." In fact, a wholly separate survey, this one using the Eysenck Personality Inventory and Eysenck Personality Questionnaire rather than the Myers-Briggs test, indicates that extraversion scores have increased over time (from 1966 to 1993) for both men and women: see Jean M. Twenge, "Birth Cohort Changes in Extraversion: A Cross-Temporal Meta-a.n.a.lysis, 19661993," Personality and Individual Differences 30 (2001): 73548.

14. United States is among the most extroverted of nations: This has been noted in two studies: (1) Juri Allik and Robert R. McCrae, "Toward a Geography of Personality Traits: Patterns of Profiles Across 36 Cultures," Journal of Cross-Cultural Psychology 35 (2004): 1328; and (2) Robert R. McCrae and Antonio Terracciano, "Personality Profiles of Cultures: Aggregate Personality Traits," Journal of Personality and Social Psychology 89:3 (2005): 40725.

15. Talkative people, for example: William B. Swann Jr. and Peter J. Rentfrow, "Blirtatiousness: Cognitive, Behavioral, and Physiological Consequences of Rapid Responding," Journal of Personality and Social Psychology 81, no. 6 (2001): 116075.

16. Velocity of speech counts: Howard Giles and Richard L. Street Jr., "Communicator Characteristics and Behavior," in M. L. Knapp and G. R. Miller, eds., Handbook of Interpersonal Communication, 2nd ed. (Thousand Oaks, CA: Sage, 1994), 10361. (But note some good news for introverts: slow speech can be perceived as honest and benevolent, according to other studies.)

17. the voluble are considered smarter: Delroy L. Paulhus and Kathy L. Morgan, "Perceptions of Intelligence in Leaderless Groups: The Dynamic Effects of Shyness and Acquaintance," Journal of Personality and Social Psychology 72, no. 3 (1997): 58191.

18. one informal study: Laurie Helgoe, Introvert Power: Why Your Inner Life Is Your Hidden Strength (Naperville, IL: Sourcebooks, 2008), 34.

19. the theory of gravity: Gale E. Christianson, Isaac Newton (Oxford University Press, Lives and Legacies Series, 2005).

20. the theory of relativity: Walter Isaacson, Einstein: His Life and Universe (New York: Simon & Schuster, 2007), 4, 12, 18, 2, 31, etc.

21. W. B. Yeats's "The Second Coming": Michael Fitzgerald, The Genesis of Artistic Creativity: Asperger's Syndrome and the Arts (London: Jessica Kingsley, 2005), 69. See also Ira Progoff, Jung's Psychology and Its Social Meaning (London: Routledge, 1999), 11112.

22. Chopin's nocturnes: Tad Szulc, Chopin in Paris: The Life and Times of the Romantic Composer (New York: Simon & Schuster, 2000), 69.

23. Proust's In Search of Lost Time: Alain de Botton, How Proust Can Change Your Life (New York: Vintage International), 1997.

24. Peter Pan: Lisa Chaney, Hide-and-Seek with Angels: A Life of J. M. Barrie (New York: St. Martin's Press, 2005), 2.

25. Orwell's 1984 and Animal Farm: Fitzgerald, The Genesis of Artistic Creativity, 89.

26. Charlie Brown: David Michaelis, Schulz and Peanuts: A Biography (New York: Harper, 2007).

27. Schindler's List, E.T., and Close Encounters of the Third Kind: Joseph McBride, Steven Spielberg: A Biography (New York: Simon & Schuster, 1997), 57, 68.

28. Google: Ken Auletta, Googled: The End of the World as We Know It (New York: Penguin, 2009), 32

29. Harry Potter: Interview of J. K. Rowling by Shelagh Rogers and Lauren McCormick, Canadian Broadcasting Corp., October 26, 2000.

30. "Neither E=mc2 nor Paradise Lost": Winifred Gallagher, I.D.: How Heredity and Experience Make You Who You Are (New York: Random House, 1996), 26.

31. vast majority of teachers believe: Charles Meisgeier et al., "Implications and Applications of Psychological Type to Educational Reform and Renewal," Proceedings of the First Biennial International Conference on Education of the Center for Applications of Psychological Type (Gainesville, FL: Center for Applications of Psychological Type, 1994), 26371.

32. Carl Jung had published a bombsh.e.l.l: Carl G. Jung, Psychological Types (Princeton, NJ: Princeton University Press, 1971; originally published in German as Psychologische Typen [Zurich: Rascher Verlag, 1921]), see esp. 33037.

33. the majority of universities and Fortune 100 companies: E-mail to the author, dated July 9, 2010, from Leah L. Walling, director, Marketing Communications and Product Marketing, CPP, Inc.

34. introverts and extroverts differ in the level of outside stimulation ... Many have a horror of small talk: See Part Two: "Your Biology, Your Self?"

35. introvert is not a synonym for hermit: Introversion is also very different from Asperger's syndrome, the autism spectrum disorder that involves difficulties with social interactions such as reading facial expressions and body language. Introversion and Asperger's both can involve feeling overwhelmed in social settings. But unlike people with Asperger's, introverts often have strong social skills. Compared with the one third to one half of Americans who are introverts, only one in five thousand people has Asperger's. See National Inst.i.tute of Neurological Disorders and Stroke, Asperger Syndrome Fact Sheet, http://www.ninds.nih.gov/disorders/asperger/detail_asperger.htm.

36. the distinctly introverted E. M. Forster: Sunil k.u.mar, A Companion to E. M. Forster, vol. 1 (New Delhi: Atlantic Publishers and Distributors, 2007).