Informational intra‐group influence: the effects of time pressure and group size

The judgments of groups have immense impact on our daily lives. This paper theorizes that three families of intra‐group influence affect the collective estimation process. These different forms of influence map to different levels of task demonstrability, or the extent to which correct answers are transparent to problem‐solvers. When demonstrability is low, group estimates are disproportionately influenced by proposals closer to the intra‐group mean (centrality). When demonstrability is high and groups are small, group decisions are disproportionately influenced by proposals closer to the correct answer (accuracy). Finally, when demonstrability is high and groups are larger, group decisions are disproportionately influenced by proposals offered by generally more accurate individuals across a set of judgments (expertise). Three laboratory studies support our predictions with regard to informational influence in cooperative groups. Copyright © 2006 John Wiley & Sons, Ltd.