The role of information in collective decisions

In this paper, we study collective information acquisition in groups that make decisions using majority rule. We argue both theoretically and experimentally that the median voter theorem does not apply; in general, the level of information acquired by the group is not equal to the level of information a median voter would like to acquire individually, despite agents having single peaked preferences over information. We find t hat g roups o veracquire o r underacquire information relative to what would have been predicted by the median voter theorem depending on the levels of disagreemnent among the group members both before and after information is acquired. We also discuss the impact of the failure of the median voter theorem on efficiency.