21. Clearly Facebook is an imperfect representation of everyone’s friendship network: Not everyone is on Facebook, so some close friends may be missing, while many “friends” are barely acquainted in real life. Counting mutual friends can help differentiate between genuine and illusory friendships, but this method is also imperfect, as even casual acquaintances on Facebook may share many mutual friends. A better approach would be to observe how frequently friends communicate or perform other kinds of relational acts (e.g., clicking on a newsfeed item, commenting, liking, etc.); however, this data is not yet available to third-party developers.
22. For details of the Friend Sense study, see Goel, Mason, and Watts (2010).
23. Projection is a well-studied phenomenon in psychology, but it has been difficult to measure in social networks, for much the same reasons that have stymied network research in general. For a review of the projection literature, see Krueger and Clement (1994), Krueger (2007), and Robbins and Krueger (2005).
24. See Aral, Muchnik, and Sundararajan (2009) for a recent study of influence in viral marketing.
25. For other recent work using e-mail data see, Tyler et al. (2005), Cortes et al. (2003), Kossinets and Watts (2006), Malmgren et al. (2009), De Choudhury et al. (2010), and Clauset and Eagle (2007). For related work using cell-phone data, see Eagle et al. (2007) and Onnela et al. (2007); and for work using instant messaging data, see Leskovec and Horvitz (2008).
26. For information on the progress on cancer see an excellent series of articles, “The Forty Years War” published in the New York Times. Search “forty years war cancer” or go to http://bit.ly/c4bsc9. For a similar account of the genomics revolution, see recent articles by Wade (2010) and Pollack (2010).
27. I have made a similar argument elsewhere (Watts 2007), as have a number of other authors (Shneiderman 2008; Lazer et al. 2009).
ABOUT THE AUTHOR
Duncan Watts is a principal research scientist at Yahoo! Research, where he directs the Human Social Dynamics group. Prior to joining Yahoo!, he was a full professor of sociology at Columbia University, where he taught from 2000 to 2007. His research on social networks and collective behavior has appeared in a wide range of journals from Nature, Science, and Physical Review Letters to the American Journal of Sociology and the Harvard Business Review. He is the author of two previous books, Six Degrees: The Science of a Connected Age (W.W. Norton, 2003) and Small Worlds: The Dynamics of Networks Between Order and Randomness (Princeton University Press, 1999). He holds a BSc in physics from the Australian Defence Force Academy, from which he also graduated with an officer’s commission in the Royal Australian Navy, and a PhD in theoretical and applied mechanics from Cornell University. He lives in New York City.
Table of Contents
Title Page
Copyright
Dedication
Contents
Preface: A Sociologist’s Apology
Part I - Common Sense
Chapter 1 - The Myth of Common Sense
Chapter 2 - Thinking About Thinking
Chapter 3 - The Wisdom (and Madness) of Crowds
Chapter 4 - Special People
Chapter 5 - History, the Fickle Teacher
Chapter 6 - The Dream of Prediction
Part II - Uncommon Sense
Chapter 7 - The Best-Laid Plans
Chapter 8 - The Measure of All Things
Chapter 9 - Fairness and Justice
Chapter 10 - The Proper Study of Mankind
Acknowledgments
Bibliography
Notes
About the Author
Everything Is Obvious Page 34