An experimental study of voting rules and polls in three-candidate elections

The authors report the results of elections conducted in a laboratory setting, modelled on a three-candidate example due to Borda. By paying subjects conditionally on election outcomes, they create electorates with (publicly) known preferences. The authors compare the results of experiments with and without non-binding pre-election polls under plurality rule, approval voting, and Borda rule. They also refer to a theory of voting ‘equilibria’, which makes sharp predictions concerning individual voter behavior and election outcomes. The authors find that Condorcet losers occasionally win regardless of the voting rule or presence of polls. Duverger’s law (which asserts the predominance of two candidates) appears to hold under plurality rule, but close three-way races often arise under approval voting and appears to hold under plurality rule, but close three-way races often arise under approval voting and Borda rule. Voters appears to poll and vote strategically. In elections, voters usually cast votes that are consistent with some stragetic equilibrium. By the end of an election series, most votes are consistent with a single equilibrium, although that equilibrium varies by experimental group and voting rule.