Cached Jan. 20, 2010, from a link at
http://papers.ssrn.com/sol3/cf_dev/AbsByAuth.cfm?per_id=16333


Preliminary draft 11/21/08
All rights reserved


“She Said WHAT?” “He Did THAT?” Believing False Rumors

Cass R. Sunstein*

“Each rumor has its own public. . . . Occupational and social groups all have their
peculiar susceptibilities. . . . A rumor public exists whenever there is a community of
interest.”[1]

I. The Problem

With the rise of the Internet, false rumors are ubiquitous. Many of them involve
famous people.[2] For example, numerous Americans have believed that Barack Obama is
a Muslim, that he was not born in the United States, and that he “palls around with
terrorists.” False rumors are pervasive about the allegedly terrible acts, beliefs, and
motivations of public officials and about the allegedly scandalous private lives not only
of those officials, but of many other people with a high public profile. In the era of the
Internet, it is easy to spread false rumors about almost anyone. A student, a professor, a
banker, an employer, an insurance broker, a real estate agent – each of these is vulnerable
to an allegation that can have a painful, damaging, or even devastating effect. If the
allegation appears on the Internet, those who google the relevant name will immediately
learn about it. The allegation will help to define the person. (It might even end up on
Wikipedia, at least for a time.) The false rumor can involve organizations – the Central
Intelligence Agency, General Motors, Bank of America, the Boy Scouts, the Catholic
Church – as well as individuals. And because material on the Internet tends to have
considerable longevity, and may even be permanent (for all practical purposes), a false
rumor can have an enduring effect.

My goal in this essay is to specify some of the mechanisms that lead to the
acceptance of false rumors, even destructive and bizarre ones.[3] Rumor transmission often
involves the rational processing of information,[4] in a way that leads people, quite sensibly
in light of their existing knowledge, to believe and to spread falsehoods.[5] This problem is
especially acute on the Internet. As we shall see, rumors often arise and gain traction
because of their relationship with the prior convictions of those who accept them.


[1] Gordon Allport and Leo Postman, The Psychology of Rumor 180 (1948).
[2] For a valuable catalogue, see http://www.snopes.com/
[3] For an overlapping account, exploring some related themes, see Cass R. Sunstein and
Adrian Vermeule, Conspiracy Theories, J. Polit Phil (forthcoming 2009).
[4] See Russell Hardin, The Crippled Epistemology of Extremism, in Political Rationality
and Extremism 3, 16 (Albert Breton et al. eds.) (Canbridge: Cambridge University Press,
2002).
[5] An illuminating treatment is Terry Ann Knopf, Rumors, Race and Riots (2d ed 2006).
My focus is on false rumors, but of course that problem is part of a larger one, including
invasion of privacy (with true information) and claims and statements that whether or not
true, are not especially important to public discussion (such as contemptuous statements
about people’s physical appearance). Much of the discussion here bears on the larger
constellation of problems.

* Felix Frankfurter Professor of Law, Harvard Law School. I am grateful to Martha
Nussbaum and Richard Posner for valuable comments and to Edward Glaeser for
valuable discussions; some of the discussion here is elaborated and formalized in joint
work-in-progress. See Edward Glaeser and Cass R. Sunstein, The Polarizing Effect of
Information (unpublished manuscript 2008). Thanks to the participants in a conference at
the University of Chicago Law School for many comments, which produced valuable
improvements.