I have (together with Petra Sundström and Anna Ståhl) been exploring the idea of an affective loop where users step by step interpret, become influenced, imitate and become involved with the system, both physically and cognitively. Petra defines an affective loop to be an interaction with some system where:

• the user first expresses her emotions through some physical interaction involving the body, for example, through gestures or manipulations of an artifact,
• the system (or another user through the system) then responds through generating affective expression, using for example, colors, animations, and haptics,
• this in turn affects the user (both mind and body) making the user respond and step-by-step feel more and more involved with the system

We have created several demos that embody some of our ideas. The most important one is the eMoto system where users express emotions in a mobile text messaging system through gestures with the stylus that comes with the mobile phone. We have extended the stylus with a couple of sensors to pick up on the gestures users perform. The gestures are translated into a colourful animated background to the SMS-message. Petra Sundström has written a licentiate thesis (2005) on the service and the design of the gestures and Anna Ståhl has written a licentiate thesis on the design process of the colours, shapes and animations in eMoto (2006).

Together with Microsoft we have build an affective diary that embody the affective loop idea in a different way.

Acknowledgement
This work has been inspired by the ideas developed by the affective presence group. The affective presence group is a loosely connected group of researchers who are all interested in creating affective interactive systems or devices that trigger social and emotional engagement and reflection. Members of the group are Phoebe Sengers at Cornell, Kirsten Boehner at Cornell, Michael Mateas from Georgia Tech., Bill Gaver at Goldsmiths in London, Geri Gay at Cornell, and Katherine Isbister at RPI.

Another strong influence to the affective loop idea was the work by Ana Paiva and our work on the SenToy project that we did jointly in the EU-funded SAFIRA project.

References

Höök, K (2004) User-Centred Design and Evaluation of Affective Interfaces, In From Brows to Trust: Evaluating Embodied Conversational Agents, Edited by Zsofia Ruttkay and Catherine Pelachaud, Published in Kluwer's Human-Computer Interaction Series PDF

Anna Ståhl (2006) Designing for Emotional Expressivity, Licenciate Thesis, Institute of Design, Umeå University, Umeå, Sweden. PDF

Petra Sundström (2005) Exploring the Affective Loop, Licenciate Thesis, Stockholm University, Stockholm, Sweden. PDF

Petra Sundström, Anna Sthl, and Kristina Höök (2006) A Wild Evaluation of Users Emotional Engagement, Contribution to the WP9 Workshop on Innovative Approaches for Evaluating Affective Systems, Stockholm, Sweden.

Anna Ståhl, Petra Sundström, and Kristina Höök (2005) A Foundation for Emotional Expressivity, In Proceedings of DUX 2005, San Francisco, CA, USA.

Petra Sundström, Anna Ståhl, and Kristina Höök (2005) A User-Centred Approach to Affective Interaction, In Lecture Notes in Computer Science, Springer.

Petra Sundström, Anna Ståhl, and Kristina Höök (2005) eMoto - Affectively Involving both Body and Mind, In Extended abstract CHI2005, Portland, Oregon, USA.

Petra Fagerberg, Anna Ståhl, and Kristina Höök (2004) eMoto - Emotionally Engaging Interaction, In Journal of Personal and Ubiquitous Computing, Special Issue on Tangible Interfaces in Perspective, Springer.

Petra Fagerberg, Anna Ståhl, and Kristina Höök (2003) Designing Gestures for Affective Input: an Analysis of Shape, Effort and Valence, In Proceedings of Mobile Ubiquitous and Multimedia, MUM 2003, Norrköping, Sweden.