When Are Two Heads Better than One and Why?

Joint Decisions In many instances, decisions made by relatively homogeneous groups (two or more people) coalesce around the choice that people are most confident in, and this in turn stems from the sampling of representations that individuals perform when making their choices. Koriat (p. 360 ; see the Perspective by Hertwig ) found that if most of the group members are able to form accurate judgments, then confidence and accuracy coincide and the consensus choice is the correct one. By contrast, if few people know the right answer, then heterogeneity in people's representations appeared to offer a surer path to accuracy.