Man-Bites-Dog Contagion: Disproportionate Diffusion of Information about Rare Categories of Events
56 Pages Posted: 16 Mar 2021
Date Written: January 28, 2021
How do social networks affect the diffusion of information? While previous research has mainly focused on the spread of specific messages, we study how the overall mix of information that diffuses through multiple intermediaries can become distorted or biased based on what categories of information people pass on versus filter out. We conducted randomized online laboratory experiments of diffusion through multi-step social networks. We find support for our pre-registered hypotheses that (1) the further someone is down a diffusion chain, the more the mix of information that they receive is biased toward rare categories of events because (2) information about rare categories of events is passed on disproportionately frequently. Our data is consistent with a preference for variety in what is shared, as well as a perceptual bias in favor of rare events. We name the disproportionate diffusion of rare categories of events "Man-Bites-Dog Contagion." Even when people intend to be accurate and informative, multi-step diffusion risks de-emphasizing the importance of empirically common categories of events and over-emphasizing the importance of empirically rare categories of events.
Keywords: Information diffusion, social networks, collective intelligence, social media, network experiment
JEL Classification: M15,M31
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