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The Speed of Social Learning

Harel, Matan and Mossel, Elchanan and Strack, Philipp and Tamuz, Omer (2014) The Speed of Social Learning. . (Submitted)

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We study how effectively a group of rational agents learns from repeatedly observing each others' actions. We find that, in the long-run, observing discrete actions of others is significantly less informative than observing their private information: only a fraction of the private information is transmitted. We study how this fraction depends on the distribution of private signals. In a large society, where everyone's actions are public, this fraction tends to zero, i.e., only a vanishingly small share of the information is aggregated. We identify groupthink as the cause of this failure of information aggregation: As the number of agents grows, the actions of each individual depend more and more on the past actions of others, thus revealing less private information.

Item Type:Report or Paper (Discussion Paper)
Related URLs:
URLURL TypeDescription Paper
Tamuz, Omer0000-0002-0111-0418
Additional Information:We thank seminar audiences in Berkeley, Berlin, Bonn, Caltech, Chicago, Düsseldorf, Duke, Microsoft Research New England, Medellín, Montreal, NYU, Penn State, Pittsburgh, Princeton, San Diego, UPenn, USC and Washington University, as well as Nageeb Ali, Ben Brooks, Dirk Bergemann, Kim Border, Federico Echenique, Benjamin Golub, Rainie Heck, Steven Morris, Luciano Pomatto, Lones Smith, Leeat Yariv and others for insightful comments and discussions. Elchanan Mossel is supported by ONR grant N00014-16-1-2227 and NSF grant CCF 1320105. Matan Harel was partially supported by the IDEX grant of Paris-Saclay.
Funding AgencyGrant Number
Office of Naval Research (ONR)N00014-16-1-2227
Record Number:CaltechAUTHORS:20170712-133000631
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:79017
Deposited By: Tony Diaz
Deposited On:12 Jul 2017 21:23
Last Modified:03 Oct 2019 18:15

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