Int. J. Human-Computer Studies 65 (2007) 329–347 A fuzzy physiological approach for continuously modeling emotion during interaction with play technologies Regan L. Mandryk à , M. Stella Atkins School of Computing Science, Simon Fraser University, Burnaby, BC, Canada V5A 1S6 Available online 10 January 2007 Abstract The popularity of computer games has exploded in recent years, yet methods of evaluating user emotional state during play experiences lag far behind. There are few methods of assessing emotional state, and even fewer methods of quantifying emotion during play. This paper presents a novel method for continuously modeling emotion using physiological data. A fuzzy logic model transformed four physiological signals into arousal and valence. A second fuzzy logic model transformed arousal and valence into five emotional states relevant to computer game play: boredom, challenge, excitement, frustration, and fun. Modeled emotions compared favorably with a manual approach, and the means were also evaluated with subjective self-reports, exhibiting the same trends as reported emotions for fun, boredom, and excitement. This approach provides a method for quantifying emotional states continuously during a play experience. r 2006 Elsevier Ltd. All rights reserved. Keywords: Emotion; Affective computing; Fun; Games; Physiology; Galvanic skin response; Electromyography; Heart rate 1. Introduction Computer games have grown during recent years into a very popular entertainment form with a wide variety of game types and a large consumer group spread across the world. As researchers develop novel play environments, computer and console game markets continue to grow rapidly, outperforming the film industry in terms of total revenues in many regions (Pagulayan et al., 2002). Although gaming technology has continued to evolve, researchers and traditional computer game developers suffer from a lack of effective evaluation methods. The development of evaluation methodologies in hu- man–computer interaction research (HCI) has been rooted in the cognitive sciences of psychology and human factors, in the applied sciences of engineering, and in computer science (Norman, 2002). Although the study of human cognition has made significant progress in the last decade, the idea of emotion, which is equally important to design (Norman, 2002), is still not well understood, especially when the primary goals are to challenge and entertain the user. Traditional measures for productivity environments, such as task performance, are not applicable to affective environments since we are not interested in performance; we are interested in what kind of emotional experience is provided by the play technology and environment, regard- less of performance (Pagulayan et al., 2002). Although traditional usability measures may still be relevant, they are subordinate to the emotional experiences resulting from interaction with the play technology and with other players. Our research interest is in how to quantify emotional experience when engaged with affective technologies, by developing an evaluation methodology for entertainment environments that is as robust as methods for evaluating productivity. This paper motivates why we need such an approach and describes the process by which we designed a new evaluative methodology for measuring emotional experience with interactive entertainment technologies. ARTICLE IN PRESS www.elsevier.com/locate/ijhcs 1071-5819/$ - see front matter r 2006 Elsevier Ltd. All rights reserved. doi:10.1016/j.ijhcs.2006.11.011 à Corresponding author. Faculty of Computer Science, Dalhousie University, 6050 University Ave., Halifax, NS, B3H 1W5, Canada. Tel.: +1 902 494 1040; fax: +1 902 492 1517. E-mail addresses: rlmandry@cs.sfu.ca (R.L. Mandryk), stella@cs.sfu.ca (M.S. Atkins).