Learning through the Grapevine: The Impact of Noise and the Breadth and Depth of Social Networks

18 Pages Posted: 7 Dec 2018 Last revised: 14 Oct 2021

See all articles by Matthew O. Jackson

Matthew O. Jackson

Stanford University - Department of Economics; Santa Fe Institute

Suraj Malladi

Cornell University, Department of Economics; Stanford University, Graduate School of Business

David McAdams

Duke University - Fuqua School of Business

Date Written: March 1, 2019

Abstract

We study how communication platforms can improve social learning without censoring or fact-checking messages, when they have members who deliberately and/or inadvertently distort information. We analyze message fidelity as a function of social network depth (how many times information is relayed) and breadth (the number of relay chains accessed). Message fidelity can be improved by capping depth or, if that is not possible, limiting breadth; e.g., by capping the number of people to whom someone can forward a given message. Although they reduce total communication, such caps increase the fraction of received messages originating closer to the receiver, thereby increasing the signal to noise ratio. We characterize how the expected number of true minus false messages depends on breadth and depth of the network and the noise structure.

Keywords: Social Learning, Communication, Noise, Mutation, Bias, Fake News

JEL Classification: D83, D85, L14, O12, Z13

Suggested Citation

Jackson, Matthew O. and Malladi, Suraj and McAdams, David, Learning through the Grapevine: The Impact of Noise and the Breadth and Depth of Social Networks (March 1, 2019). Available at SSRN: https://ssrn.com/abstract=3269543 or http://dx.doi.org/10.2139/ssrn.3269543

Matthew O. Jackson (Contact Author)

Stanford University - Department of Economics ( email )

Landau Economics Building
579 Serra Mall
Stanford, CA 94305-6072
United States
1-650-723-3544 (Phone)

HOME PAGE: http://www.stanford.edu/~jacksonm

Santa Fe Institute

1399 Hyde Park Road
Santa Fe, NM 87501
United States

Suraj Malladi

Cornell University, Department of Economics ( email )

Ithaca, NY
United States

HOME PAGE: http://https://economics.cornell.edu/suraj-malladi

Stanford University, Graduate School of Business ( email )

Stanford, CA
United States

David McAdams

Duke University - Fuqua School of Business ( email )

Box 90120
Durham, NC 27708-0120
United States

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