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 information (i.e., information that only one group member or another possesses prior to discussion) exchanged within groups is related to group-judgment accuracy when the correct response is not apparent to the members prior to discussion. Thirty-nine 3-person groups were asked to make a series of 36 judgments 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 information) and part of which was divided among them (unshared information). Moreover, this information was distributed to the members in such a way that their 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 discussed and group accuracy on hidden-profile cases. Instead, the results suggested that group accuracy was determined by how accurate members were prior to discussion and that the vital role of group discussion was not to exchange information but to aggregate member judgments into a consensual group judgment.