Abstract. We survey research on multi-user brain-computer interfacing applications and look in particular at 'multi-brain games'. That is, games where in one or other form the (EEG-) measured brain activity of more than one user is needed to play the game. Various ways of integrating and merging brain activity in a game context are investigated. Existing research games are mentioned, but the emphasis is on surveying BCI research that will provide ideas for future multi-brain BCI games.Keywords: brain-computer interfaces, multi-brain games, social games.
IntroductionIn previous years we have seen a growing interest in brain-computer interfacing (BCI) in the human-computer interaction (HCI) community. Before that, BCI was researched with the aim to help disabled persons and provide them, among other things, with a hands-free 'communication channel' to type messages, to control prostheses, or to navigate a wheelchair. Our research, instead, has focused on BCI for 'healthy' users, in particular on its use for games [1,2]. There are good reasons to do so. In games and entertainment applications we are not limited by thoughts and concerns that relate to patients and disabled persons. We can use our fantasy and can allow situations and events in non-real-life situations, happening in virtual worlds. We can allow cooperation and competition with multiple and distributed users and we can allow interaction modalities and effects that are unusual but can be believable, depending on the design of the game. Gamers don't behave as disabled people in need. They have different motivations and expectations. That introduces problems and new challenges. Game designers have to design for challenges or otherwise to make use of the existing challenges in a meaningful manner, rather than to avoid them. In 2012 a roadmap for BCI research appeared [3]. The roadmap was initiated by the FP7 research program of the European Union. Unfortunately, the roadmap stayed close to traditional BCI research. It hardly took into account new research opportunities coming from embedding BCI research in HCI research, in particular multimodal interaction [4,5] and artificial intelligence research. The problems (or