The impact of information on small group choice.

The impact of information on an aggregate decision is directly related to the number of members of the aggregate who know the information prior to the group decision. This experiment obtains this common knowledge effect in small group choice. Group discussion affects group choice in some cases, signaled by group choices that overturn the choice of a majority of the group members. In those overturned majorities, moreover, the group tended to choose the correct option, leading group choices to be more accurate than member choices. Consistent with results comparing individual judgment and choice, groups pool information less thoroughly and rely on prominent items of information more heavily when choosing as compared with estimating.

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