Divided Majority and Information Aggregation: Theory and Experiment
60 Pages Posted: 1 Feb 2013
Date Written: November 2012
This paper both theoretically and experimentally studies the properties of plurality and approval voting when the majority is divided as a result of information imperfections. The minority backs a third alternative, which the majority views as strictly inferior. The majority thus faces two problems: aggregating information and coordinating to defeat the minority candidate. Two types of equilibria coexist under plurality: either voters aggregate information, but this requires splitting their votes, or they coordinate but cannot aggregate information. With approval voting, expected welfare is strictly higher, because some voters multiple vote to achieve both goals at once. In the laboratory, we observe both types of equilibrium under plurality. Which one is selected depends on the size of the minority. Approval voting vastly outperforms plurality. Finally, subject behavior suggests the need to study asymmetric equilibria.
Keywords: Approval Voting, Experiments, Multicandidate Elections, Plurality
JEL Classification: C72, C92, D70, P16
Suggested Citation: Suggested Citation