Ignorance and bias in collective decisions

Abstract

ABSTRACT. We study theoretically and experimentally a committee with common interests. Committee members do not know which of two alternatives is the best, but each member can acquire privately a costly signal before casting a vote under either majority or unanimity rule. In the experiment, as predicted by Bayesian equilibrium, voters are more likely to acquire information under majority rule, and attempt to counter the bias in favor of one alternative under unanimity rule. As opposed to Bayesian equilibrium predictions, however, many committee members vote when uninformed. Moreover, uninformed voting is strongly associated with a lower propensity to acquire information. We show that an equilibrium model of subjective prior beliefs can account for both these phenomena, and provides a good overall fit to the observed patterns of behavior both in terms of rational ignorance and biases. On trouve de plus, que si la probabilité de la voix de chaque Votant est plus grande que 1 2 , c'est-à-dire, s'il est plus probable qu'il jugera conformément à la vérité, plus le nombre des Votans augmentera, plus la probabilité de la vérité de la décision sera grande : la limite de cette probabilité sera la certitude [. . . ] Une assemblée très-nombreuse ne peut pas être composée d'hommes très-éclairés; il est même vraisemblable que ceux qui la forment joindront sur bien des objets beaucoup d'ignorance à beaucoup de préjugés. Condorcet (1785) [1986, p. 29-30]

Voter motivation and the quality of democratic choice

“…However, the observed rates of such counterproductive behavior are low (12%, 3%, and 1%, respectively) in our experiment compared to other studies that also allow for such behavior. For example, Grosser and Seebauer (2016) find rates of uninformed voting that are almost three time (about 30 percent) and Elbittar et al (2014) about 5 times as large in comparable cases. We think that we observe much lower rates of uninformed voting because our naturalistic framing of the choice situation reduces confusion and facilitates subjects' understanding.…”

Fake News, Voter Overconfidence, and the Quality of Democratic Choice

“…There have been various theoretical extensions of Feddersen and Pesendorfer (1996), such as Feddersen and Pesendorfer (1999) and McMurray (2019b)). 41 Our study di¤ers from this literature (with the exception of Elbittar et al (2016)) in that people hold subjective (rather than objectively correct) beliefs about the quality of the news they receive. Elbittar et al (2016) studies information aggregation under unanimity and majority rules in a common interest setting where each group member is initially uninformed about which of two alternatives is optimal but may choose to acquire a noisy information signal at a cost.…”

Individual Competence and Committee Decision Making: Experimental Evidence

“…For example, Bhattacharya, Duffy, and Kim () discusses whether voters are sophisticated enough to recognize the free riding potential. Elbittar et al () explain their findings through biased and occasionally mistaken voting behavior. We, alternatively, explore the possibility of non‐monetary preference explanations for the outcomes observed.…”

“…They record an overinvestment, relative to theory's predictions. Elbittar et al (2017) focus on the opportunity for a voter to abstain and Großer and Seebauer (2016) extend the analysis of abstention to a comparison between compulsory and voluntary voting. Both document subjects choosing to remain uninformed and opting to vote.…”