Primetime Spin:
Media Bias and Belief Conrming Information
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Jeremy Burke
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February 2007
Abstract
This paper develops a model of media bias in which rational agents acquire all their news
from the source that is most likely to conrm their prior beliefs. Despite only wishing to make
the correct decision, agents act as if they enjoy receiving news that supports their precon-
ceptions. By exclusively gathering information from a source biased towards his prior, there
is little chance an agent will be persuaded to change his mind. Moreover, it is shown that
even an unbiased agent prefers to receive biased news as it is unlikely to produce con
icting
reports. The media caters to the informational demands of consumers and accordingly slants
its reporting. It is shown that competition may not decrease bias, but may actually enhance
it. Finally, even when it increases bias, competition may improve welfare by expanding the
market for news.
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I thank John Aldrich, Scott de Marchi, Dan Graham, Jay Hamilton, Michael Munger, Curtis Taylor, and Huseyin
Yildirim for helpful comments and suggestions.
y
Department of Economics, Duke University, Box 90097, Durham, NC 27708-0097, email: Jeremy.## email not listed ##
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