How to stay in the emotional rollercoaster: lessons learnt from designing EmRoll

Bodily expressions can be used to involve players in intense experiences with games. By physically moving, breathing, or increasing your pulse, you may start emotional processes that help create for a stronger experience of the narrative in the game. We have designed a system named EmRoll that poses riddles to pairs of players. The riddles can only be solved if the players are, or at least pretend to be, moving according to different emotional states: dancing happily, relaxed breathing and being scared. The system measures movement, breathing and sweat reactions from the two pl ayer s. Lessons learnt were: playing in pairs is an important aspect as the two players influenced one-another, pulling each other into stronger experiences; getting excited through intense movement when involving your whole body worked well, as did relaxing through deep breathing; using the sweat response as an input mechanism worked less well; and finally, putting a Wizard (a human operator) into the loop can help bootstrap difficulty balancing and thereby increase emotional involvement.