Optimal group decision: A matter of confidence calibration

The failure of groups to make optimal decisions is an important topic in human sciences. Recently this issue has been studied in perceptual settings where the problem could be reduced to the question of an optimal integration of multiple signals. The main result of these studies asserts that inefficiencies in group decisions increase with the heterogeneity of its members in terms of performances. We assume that the ability of agents to appropriately combine their private information depends on how well they evaluate the relative precision of their information. We run two perceptual experiments with dyadic interaction and confidence elicitation. The results show that predicting the performance of a group is improved by taking into account its members' confidence in their own precision. Doing so allows us to revisit previous results on the relation between the performance of a group and the heterogeneity of its members' abilities.