INFORMATION AGGREGATION, RATIONALITY, AND THE CONDORCET JURY THEOREM

The Condorcet July Theorem states that majorities are more likely than any single individual to select the ''better'' of two alternatives wh en there exists uncertainty about which of the two alternatives is in fact I preferred Most extant proofs of this theorem implicitly make th e behavioral assumption that individuals vote ''sincerely'' in the col lective decision making, a seemingly innocuous assumption, given that individuals are taken to possess a common preference for selecting the better alternative. However, in the model analyzed here we find that sincere behavior by all individuals is not rational even when individu als have such a common preference. In particular, sincere voting does not constitute a Nash equilibrium. A satisfactory rational choice foun dation for the claim that majorities invariably ''do better'' than ind ividuals, therefore, has yet to be derived.