The influence of task demands on joint action planning

Joint actions require co-actors to coordinate their individual contributions to achieve joint goals. One proposal is that such coordination is supported by joint action plans. However, it remains unclear whether joint action planning is generally prioritized, or whether it is flexibly engaged depending on task demands. Here, we investigated the factors that influence co-actors' propensity to use the individual- and joint-level planning. Pairs of participants performed a joint task in which pre-cues provided information about individual contributions, the relation between contributions, or both. We manipulated the flexibility required to map actions onto outcomes, the order in which individual- and joint-level information was provided, and the relation between individual contributions. When mapping actions onto their outcomes required little flexibility, cues about the relation between individual contributions provided a performance benefit, indicating a tendency to prioritize joint action planning. In contrast, when action-outcome mappings were variable and required more flexibility, co-actors refrained from a general use of joint action plans and relied primarily on individual planning. Under these conditions, joint cues improved performance only when they allowed participants to infer their own required contribution from information about their partner's contribution. The order in which individual and joint-level information was specified and the relation between individual contributions did not influence participants propensity to engage in joint action planning. Together, these findings show that joint action planning is not generally prioritized but is flexibly recruited as a function of task demands, specifically the flexibility required to map actions onto outcomes.