Group Confidence Pressures in Iterative Decisions

This study investigated the effects of two group decision making techniques on a set of four problems in groups of sizes 3, 7, and 11. Participants included 192 male and 132 female undergraduates. Estimates that could be evaluated for accuracy for each of the problems were collected for a series of three trials. One set of groups received face-to-face verbal feedback from each other, while the other set received written feedback. These data were compared to mean estimates obtained from randomly selected, pooled individual estimates. The results suggested that the pooled individual estimates were somewhat more accurate than those obtained from either of the interacting groups. At the same time, all individuals became more confident of their answers, suggesting the possibility of groupthink. No effects for different group sizes were found, possibly due to the constraints imposed by the structured nature of the two techniques.