The online ouija board : A testbed for multi-party control of dynamical systems

We introduce the online ouija board, a multiplayer server-based game in which a team of agents must coordinate their control actions in real-time, so as to drive a token across a board and spell as many words as possible in a given time. This ouija game presents several of the typical features of multi-party control systems, namely: (i) it is a networked control system, since messages between the players' individual computers and the server are affected by asynchronism, delays, and possible packet drops; (ii) it is a team theoretic/ distributed decision problem, since different players have authority over different inputs, and individual choices influence the information available to other players, and (iii) it is a distributed design problem, since, when no communication is allowed, each player control law must be chosen independently, with access to a partial description of the token's dynamics. In this paper, we propose a simple model of the ouija board which, while assuming away the complications due to (i) and (ii), allows us to focus on the distributed design aspect of the problem mentioned in (iii). We show that simple control strategies exist, which require players to know the token's position and their own actuation direction, but nothing about their teammates' directions or input values. We then compare this simple strategy to the choices made by actual human players in the ouija game, and discuss the role that team communication may play in these choices.