PUB - Publikationen an der Universität Bielefeld

Energy consumption in private households is high, with heating energy accounting for more than 60 %. The predicted energy saving potential of energetic renovations of residential buildings is often not achieved. A behaviour change towards energy-saving behaviour of the residents is necessary. For this purpose, I developed a mobile app, the Floka-App, to support and motivate users to save energy.

A theory-based development approach was used to design and implement the Floka-App, with which the psychological constructs and determinants of a behaviour change model were systematically translated into BCT in order to finally implement concrete app functions that have the desired effects on the users' behaviour. The virtual agent Floka was integrated into the app as an interaction partner that is supposed to contribute to the app's persuasive effect through its socio-emotional expressiveness. In addition, various gamification elements support the motivation for long-term use of the app.

In this thesis, I investigated the hypothesis that a mobile app implementing a well-known and validated behaviour change model in a theory-based manner, employing the socio-emotional capabilities of a virtual agent to establish a relationship with users to enhance the persuasive effect, and using gamification elements for additional motivation can successfully achieve a behaviour change towards energy-saving behaviour.

Particularly, I evaluated which factors influence behaviour change towards energy-saving behaviour within the different stages of the behaviour change model, what role the virtual agent Floka plays in this and how it is perceived, and what influence gamification elements and errors have on user motivation.

For this purpose, a long-term user study was carried out in households in Bielefeld-Sennestadt, in which the Floka-App and corresponding measuring systems were installed in about 20 households and tested for two heating periods. In addition, the design of the virtual agent Floka was evaluated in online studies, in particular its socio-emotional expressiveness, and the menu-based approach of the Floka-App was examined to determine whether tailored interventions for the individual stages of behaviour change can be omitted. This makes a regular assessment of the current stage of the user unnecessary, and an intervention for the individual needs in each stage of the behaviour change is still possible, since it is assumed that users themselves choose the function that suits their current needs.

Overall, I was able to show how a theory-based implementation of a psychological model into a mobile app can be carried out and that the users choose the functions relevant to them in a menu-based implementation. Nevertheless, the theory-based approach does not automatically lead to the desired behaviour change and the interaction of different elements for behaviour change should be considered and evaluated before use. For the use of virtual agents I was also able to show that their use does not necessarily lead to an improvement in interaction. I found that the perceived capability, knowledge and competence in particular are related to the usefulness and acceptance of a virtual agent. Emotional expressions should also be checked for their recognizability before they are used. My research has shown that an improved display of emotions leads to better ratings, but in my case higher ratings correlate negatively with the behaviour change process. Likewise, I could not show in the long-term study that errors affect the usage frequency. However, severe errors that cause the virtual agent Floka to stop moving, as expected, result in lower social attribute ratings. I also showed that the use of gamification elements does not automatically lead to an increase in user motivation, but in my case could only make a small contribution.