Contagious Why Things Catch On

Cognition and Emotion
21, 944–63.
“The most beautiful emotion”:
The Einstein quote comes from Ulam, S. M., Françoise Ulam, and Jan
Myielski (1976), 
Adventures of a Mathematician
(New York: Charles Scribner’s Sons), 289.
Awe-inspiring articles:
 Berger and Milkman, “What Makes Online Content Viral,” 192–205.
Susan Boyle’s first appearance:
 Susan Boyle’s performance can be found at 
http://jonahberger.com
.
helps deepen our social connection:
 For a discussion of how the social sharing of emotion deepens
social bonds, see Peters, Kim, and Yoshihasa Kashima (2007), “From Social Talk to Social
Action: Shaping the Social Triad with Emotion Sharing,” 
Journal of Personality and Social
Psychology
93, no. 5, 780–97.
negative content should be more viral:
 For a discussion of positive and negative word of mouth, see
Godes, Dave, Yubo Chen, Sanjiv Das, Chrysanthos Dellarocas, Bruce Pfeiffer, et al. (2005), “The
Firm’s Management of Social Interactions,” 
Marketing Letters
16, nos. 3–4, 415–28.
psychologist Jamie Pennebaker:
 A discussion of linguistic inquiry and word count can be found in:
Pennebaker, James W., Roger J. Booth, and Martha E. Francis (2007), “Linguistic Inquiry and
Word Count: LIWC2007,” accessed October 14, 2011; 
http://www.liwc.net/
. For a review of how
LIWC has been used to study a range of psychological processes, see Pennebaker, James W.,
Matthias R. Mehl, and Katie Niederhoffer (2003), “Psychological Aspects of Natural Language
Use: Our Words, Our Selves,” 
Annual Review of Psychology
54, 547–77.
the amount of positivity and negativity:
 The greater the percentage of emotional words in a passage
of text, the more emotion it tends to express. Pennebaker, J. W., and M. E. Francis (1996),
“Cognitive, Emotional, and Language Processes in Disclosure,” 
Cognition and Emotion
10, 601–
26.
newcomers falling in love with New York City:
Berger and Milkman, “What Makes Online Content
Viral,” 192–205.
Articles that evoked anger or anxiety:
 Ibid.
physiological arousal:
A great deal of research in psychology has examined the so-called two-
dimensional theory of affect (valence and arousal). For discussions, see Barrett, Lisa Feldman, and
James A. Russell (1999), “The Structure of Current Affect: Controversies and Emerging

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Consensus,” 
Current Directions in Psychological Science
8, no. 1, 10–14; Christie, I. C., and B.
H. Friedman (2004), “Autonomic Specificity of Discrete Emotion and Dimensions of Affective
Space: A Multivariate Approach,” 
International Journal of Psychophysiology
51, 143–53; and
Schlosberg, H. (1954), “Three Dimensions of Emotion,” 
Psychological Review
61, no. 2, 81–88.
This is arousal:
 For a discussion of the neurobiology of arousal, see Heilman, K. M. (1997), “The
Neurobiology of Emotional Experience,” 
Journal of Neuropsychiatry
9, 439–48.
funny content is shared:
 The result that arousal boosts social transmission can be found in Berger,
Jonah (2011), “Arousal Increases Social Transmission of Information,” 
Psychological Science
22,
no. 7, 891–93.
While traveling to a gig:
 A summary of Dave Carroll’s odyssey with United Airlines can be found in
his book: Carroll, Dave (2012), 
United Breaks Guitars: The Power of One Voice in the Age of
Social Media
(Carlsbad, CA: Hay House). To hear the actual song, go to 
http://jonahberger.com
.