Abstract— In this paper we describe a robotic game buddy whose emotional behaviour is influenced by the state of the game. Using the iCat robot and chess as the game scenario, an architecture for incorporating emotions as a result of a heuristic evaluation of the state of the game was developed. The game buddy was evaluated in two ways. First, we investigated the effects of the character’s emotional behaviour on the user’s perception of the game state. And secondly we compared a robotic with a screen based version of the iCat in terms of their influence on user’s enjoyment. The results suggested that user’s perception of the game increases with the iCat’s emotional behaviour, and that the enjoyment is higher when interacting with the robotic version. I. INTRODUCTION OBOTS are becoming part of our daily lives. In spite of the classical view that robots are more adequate for settings like mine fields or production lines, they are now becoming well accepted for household tasks (as vacuum cleaners or as entertainment robots). Indeed, in the last few years, the field of social robotics [1] has emerged as a strong field, where robots are especially designed to interact with people. Such interactions can vary from robots whose sole purpose is to entertain people, to robots that behave as assistants, helping humans to perform tasks in several domains. There are application areas where the presence of social skills in robots is indeed quite significant [2], such as entertainment, health care, tour guides and education. Emotional information exchange plays an important role in human social interaction. When interacting with robotic characters or synthetic characters, such social interaction must be carefully drafted. Indeed, current research in synthetic characters, considers that one of the principal ways to achieve believability is through emotional interaction, as it helps to know that characters are aware and “care” about what happens in the world [3]. If tomorrow's robots are going to be part of our world, they should have some emotional behaviour that allows them to communicate and respond in ways people can understand. Endowing robots with emotions can be very useful for a variety of reasons: (1) it facilitates human-robot interaction; (2) can provide feedback to the user, such as indicating the robot's internal state, goals and intentions; (3) can act as a control Authors are with the IST – Technical University of Lisbon and INESC- ID, Av. Professor Cavaco Silva - Taguspark, 2780-990 Porto Salvo, Portugal (emails: iolanda.leite@tagus.ist.utl.pt, andre.pereira@tagus.ist.utl.pt, carlos.martinho@tagus.ist.utl.pt, ana.paiva@inesc-id.pt). The research leading to these results has received funding from European Community’s Seventh Framework Programme (FP7/2007-2013) under grant agreement nº 215554. mechanism, driving behaviour and reflecting how the robot is affected by different factors over time [4]. Humans usually express emotions through speech, facial expression and/or body gestures [5]. Human expressivity has been inspirational in the area of synthetic characters (both with robotic or screen based embodiments [6][7]). However, little is known about the effects that the physical embodiments have on the user’s perception and relation with these characters. Furthermore, there are few studies comparing robotic characters to virtual synthetic characters, determining the impact that different embodiments has on factors such as engagement, attachment and so on. In this paper, we investigate the effects of emotions and embodiment in social robots that act as game companions. Regarding emotions, we analyse how the robot's emotional behaviour can help users to better understand the game they are playing. Regarding embodiment, we wanted to test if the user's enjoyment is different when we alter the embodiment between a robotic and a graphical synthetic character (although looking and acting exactly the same). The paper is organised as follows. In the next section we provide a brief literature review on social robots, with special emphasis on robots that have some emotional behaviour. Then, we describe the architecture behind our game buddy. Finally, we describe two preliminary experiments carried on to evaluate the effects of the proposed emotion model in the user’s perception of the game, and the effects of the embodiment in the user's enjoyment. We finish the paper with some conclusions and future work. II. RELATED WORK For many years emotions applied to machines were viewed as of secondary importance, yet that changed when the field of Affective Computing came along. Actually, emotions are critical in social robots, as Breazeal demonstrates in her work with Kismet [8]. The behaviour of this robot is totally determined by its emotions and it engages people by communicating its affective state and other social cues through facial expressions, gaze and affective speech. Another social robot capable of expressing emotions is eMuu, which was designed to be the interface between the environment of an intelligent home and its inhabitants. Studies involving eMuu [9] were performed to evaluate how convincing, trustworthy and intense its emotional expressions were viewed by the user, and if such expressions were appropriate in a certain situation. The results of the experiment showed that eMuu's emotions were perceived as convincing as emotional expressions of humans and also that Are Emotional Robots More Fun to Play With? Iolanda Leite, André Pereira, Carlos Martinho and Ana Paiva R