The role of information exchange in predicting group accuracy on a multiple judgment task

This study was conducted to examine whether the amount of unshared informat ion (i.e., information that only one group member or another possesses prio r to discussion) exchanged within groups is related to group-judgment accur acy when the correct response is not apparent to the members prior to discu ssion. Thirty-nine 3-person groups were asked to make a series of 36 judgme nts regarding the probability that hypothetical high school dropouts would return to school. These judgments were based on a set of information, part of which was given to all group members prior to discussion (shared informa tion) and part of which was divided among them (unshared information). More over, this information was distributed to the members in such a way that th eir individual prediscussion preferences would tend to be either inaccurate (hidden profiles) or accurate (manifest profiles), relative to the optimal group judgment based on all of the information that was given to the group as a whole (i.e., both shared and unshared information). Results indicated that there was no relation between the amount of unshared information disc ussed and group accuracy on hidden-profile cases. Instead, the results sugg ested that group accuracy was determined by how accurate members were prior to discussion and that the vital role of group discussion was not to excha nge information but to aggregate member judgments into a consensual group j udgment.