only as good as its best member. Finally, the last model tested was a control model involving random response selection. The study concluded that, when similarly skilled persons meet, they can both benefit from cooperation. A model in which participants communicate their relative confidences best explains this benefit.

We extend the models from @Bahrami2010 to groups of $n$ participants and compare their predictions. Furthermore, we add a model in which a participant either knows the correct answer, or guesses. Importantly, in the case of larger groups, it may be the case that only small subgroups of participants can communicate simultaneously. Thus, we address this issue by considering hierarchical schemes of decision aggregation, in which decisions are first made by subgroups, and then some of these subgroups interact to reach a shared decision.

The paper is organized as follows. In Section \[s:discrimination\], we present the @Bahrami2010 approach to integrating individual discrimination functions in pairs of participants. We use it to assess performance in groups. In Section \[s:communication\], we proceed to formulating a series of models of communication, which express the performance of a group of $n$ persons as a function of their individual performances. In Section \[s:aggregation\], we investigate how each 