The Role of Action Planning and Control within Joint Action

Abstract

Past work on joint action has shown that the performance of joint action improves when individuals within a pair behave using a predictable strategy. The present study sought to examine the effects of manipulating task demands on joint action planning strategies and online control. Participant pairs performed a joint task in which a Passer passed an object to a Receiver, who had to place it in a target area in a pre-determined orientation. Seven experiments varied the demands, constraints, and roles involved in each participants’ task. Experiment 1, which served as a control for the following experiments, examined the basic action planning formation amongst two individuals. Experiment 2 and 3 applied an artificial impairment in a predictable and unpredictable manner, respectively, to one of the participants to examine its effect on strategy formation relative to action planning and control. In Experiment 4 the effects of gaze cue was examined, whilst Experiment 5 increased task difficulty through the insertion of an added precision task. Experiment 6 examined the role of imitation and adopting a partner’s role during joint cooperation by swapping roles during the object passing task. Experiment 7 increased movement complexity through the application of a cube that could be rotated in 3 dimensions. Overall, it was observed that Passers were inclined to rotate the object prior to handing it to the Receiver, thereby accommodating the latter’s affordances. When task demands were varied within a session, Passer’s adopted highly consistent strategies across conditions. When roles were reversed halfway through the session, participants generally behaved as their partner had in the first block. Taken in sum, 4 these results suggest that planning a joint action is influenced by a partner’s task and the overall action goal, with predictability being an important component of strategy formation.