When two or more people coordinate their actions in space and time to produce a joint outcome, they perform a joint action. The perceptual, cognitive, and motor processes that enable individuals to coordinate their actions with others have been receiving increasing attention during the last decade, complementing earlier work on shared intentionality and discourse. This chapter reviews current theoretical concepts and empirical findings in order to provide a structured overview of the state of the art in joint action research. We (...) distinguish between planned and emergent coordination. In planned coordination, agents' behavior is driven by representations that specify the desired outcomes of joint action and the agent's own part in achieving these outcomes. In emergent coordination, coordinated behavior occurs due to perception action couplings that make multiple individuals act in similar ways, independently of joint plans. We review evidence for the two types of coordination and discuss potential synergies between them. (shrink)

When sharing a task with another person that requires turn taking, as in doubles games of table tennis, performance on the shared task is similar to performing the whole task alone. This has been taken to indicate that humans co-represent their partner’s task share, as if it were their own. Task co-representation allows prediction of the other’s responses when it is the other’s turn, and leads to response conflict in joint interference tasks. However, data from our lab cast doubt on (...) the view that task co-representation and resulting response conflict are the only or even primary source of effects observed in task sharing. Recent findings furthermore suggest another potential source of interference in joint task performance that has been neglected so far: Self-other discrimination and conflict related to agent identification (i.e., determining whether it is “my” or the other’s turn). Based on these findings we propose that participants might not always co-represent what their partner is supposed to do, but instead co-represent that another agent is responsible for part of the task, and when it is his turn. We call this account the actor co-representation account. (shrink)

The everyday concept of a social group is approached by examining the concept of going for a walk together, an example of doing something together, or "shared action". Two analyses requiring shared personal goals are rejected, since they fail to explain how people walking together have obligations and rights to appropriate behavior, and corresponding rights of rebuke. An alternative account is proposed: those who walk together must constitute the "plural subject" of a goal. The nature of plural subjecthood, the thesis (...) that social groups are plural subjects, and the relation of these ideas to Rousseau's and Hobbes 's, are briefly explored. (shrink)

Human beings act together in characteristic ways that matter to us a great deal. This book explores the conceptual, metaphysical and normative foundations of such sociality. It argues that appeal to the planning structures involved in our individual, temporally extended agency provides substantial resources for understanding these foundations of our sociality.