Shared agency occurs when two or more individuals do something together (such as carry a piece of furniture or sing a song). Collective agency occurs when two or more individuals act as a group (in accordance with certain principles or procedures that constitute and organize the group). Research on shared and collective agency has flourished over the past two decades or so. One central question has been whether shared and collective agency can be reduced to the agency of the individuals involved, or whether they are constitutive of different kinds of agency—whether they are, in some sense, something over and above individual agency. An account of collective agency in terms of the standard theory raises the question of whether it makes sense to attribute mental states and events (such as desires, beliefs, and intentions) to groups of individuals. (For references and discussion see the entries on shared agency and collective intentionality.)