Beliefs and Voting Decisions: A Test of the Pivotal Voter Model

Abstract

Abstract.We report results from a laboratory experiment that provides the first direct test of the pivotal voter model. This model predicts that voters will rationally choose to vote only if their expected benefit from voting outweighs the cost. The expected benefit calculation involves the use of the voter's subjective probability that s/he will be pivotal to the election outcome; this probability is typically unobservable. In one of our experimental treatments we elicit these subjective probabilities using a proper scoring rule that induces truthful revelation of beliefs. The cost of voting and the payoff to the election winner are known constants, so the subjective probabilities allow us to directly test the pivotal voter model. We find only weak support for the model. While a higher subjective probability of being pivotal does increase the likelihood that an individual chooses to vote, the decisiveness probability thresholds used by subjects are not as crisp as the theory would predict. We do find that individuals learn over time to adjust their probabilities of being pivotal so that they are more consistent with the historical frequency of decisiveness. In a second treatment, we eliminate the elicitation of decisiveness probabilities and find little change in the voting behavior of subjects; we conclude from this second treatment that our belief elicitation procedure does not alter the manner in which individuals make voting decisions and therefore provides a reasonable direct test of the pivotal voter model.

Experimental evidence that quorum rules discourage turnout and promote election boycotts

“…This model assumes that voting is instrumental, so that an individual's decision to vote depends on her beliefs about the likelihood of casting the decisive vote. The implications and comparative static predictions of the pivotal voter model have been supported by abundant experimental evidence (Levine and Palfrey 2007;Duffy and Tavits 2008;Palfrey 2009), while field evidence is consistent -at least in the margins -with the model's predictions about the effects of electorate size and election closeness (Blais 2000;Geys 2006). Our study is, to our knowledge, the first to test the effects of quorum rules under this framework in a controlled laboratory experiment.…”

“…Thus, it is possible that approval quora lead to lower turnout among opponents and higher turnout among supporters, leaving the aggregate level of participation unchanged. Similar concerns have motivated previous authors to conduct laboratory experiments to investigate factors affecting voter participation (Levine and Palfrey 2007;Duffy and Tavits 2008;Palfrey 2009). …”

La proportionnelle a-t-elle des effets vertueux ? Une étude expérimentale

“…40. Dans l'étude de John Duffy et Margit Tavits (2008), les volontaires participent à 20 élections consécutives sous le UT où voter est facultatif et coûteux. Notons que le taux de participation est de 40 % en moyenne lors du dernier vote dans chaque groupe.…”

“…Des expériences portant sur la participation électorale -notamment celle d'Arthur Schram et Joep Sonnemans (1996) ainsi que celle de John Duffy et Margit Tavits (2008) 32 -ont précédé la nôtre et proposé deux partis à un groupe de 20 participants. Ces derniers sont divisés en deux sous-groupes égaux partisans d'un des deux partis.…”

Dynamics of Voting Propensity: Experimental Tests of Adaptive Learning Models

“…In the rst stage, subjects are asked if they wished to cast their vote or abstain. If a subject decides to participate in the vote she has to pay a voting 5 The experiments were programmed and conducted in z-Tree (Fischbacher, 2007), which is partly inspired by the design chosen by (Duy and Tavits, 2008). cost and is admitted to the second stage in which she is oered a choice between A and B.…”