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]

We conduct a laboratory study of the group-on group ultimatum bargaining with restricted within-group interaction. In this context, we concentrate on the effect of different within-group voting procedures on the bargaining outcomes. Our experimental observations can be summarized in two propositions. First, individual responder behavior across treatments does not show statistically significant variation across voting rules, implying that group decisions may be viewed as aggregations of independent individual decisions. Second, we observe that proposer behavior significantly depends (in the manner predicted by a simple model) on the within-group decision rule in force among the responders and is generally different from the proposer behavior in the one-on-one bargaining.

No abstract

Landsberger et al. (2001) identi…ed optimal bidder behavior in …rst-price private-value auctions when the ranking of valuations is common knowledge, and derived comparative-statics predictions regarding the auctioneer's expected revenue and the e¢ ciency of the allocation. The experiment reported here tests the behavioral components of these comparative-statics predictions. The results support the prediction that buyers are inclined to bid more aggressively when they learn they have the low value. Contrary to the theory, buyers are inclined to bid less when they learn they have the high value. Once information is revealed, bidders tend to move toward better responses, exploiting new economic opportunities. Consistent with theory, the overall proportion of e¢ cient allocations is lower than in the …rst-price auction before information is revealed. But as a result of high-value bidders decreasing their bids, the expected revenue does not increase on a regular basis, contrary to the theory's predictions.

Se investiga la posibilidad de recaudar aportaciones voluntarias para el financiamiento de bienes comunes a través de dos mecanismos: confianza y correspondencia fiscal. Ambas hipótesis se evalúan empíricamente por medio de diseño experimental levantado en tres localidades rurales de México. Los resultados sugieren que la disposición a contribuir aumenta cuando el bien a financiarse es observable y que el nivel de confianza fiscal es equivalente entre la autoridad fiscal y el otro agente recaudador, como lo es el mayordomo en las comunidades rurales mexicanas, siempre y cuando el bien sea observable y tangible.