Proceedings of the Annual Meeting of the Cognitive Science Society

Human cooperation involves flexible role-taking. This form of cooperation has been attributed to collective intentionality – the ability to represent what "The Group" believes and desires. However, the factors determining when and why humans spontaneously assume roles remain understudied. We propose that a primary motivation for role-taking is to reduce coordinative complexity by making one's intentions transparent. We test this hypothesis in a naturalistic cooking study (N = 270, 90 trials) in which groups of two, three, and four collaborate, as additional members increase coordinative complexity by expanding possible task distributions and increasing inference misalignment. Our analysis shows that role-taking increases significantly with group size, supporting the hypothesis that roles are used to manage coordinative complexity. These findings provide insight into why humans choose certain cooperative strategies, suggesting that facilitating coordination and solidarity may be prioritized over optimizing productivity.