In the natural interaction with our environment, humans draw on a wealth of information without consciously focusing on it. In contrast, the vast majority of interaction with modern technological devices is accomplished through focused attention.<br />

This thesis therefore researches the use of _ambient displays_, which convey information at the periphery of attention. As a use case that has been identified as particularly suitable for such interfaces but has not yet been researched very extensively, we have focused on supporting users to act in a more environmentally-conscious way. Furthermore, despite the fact that preliminary research in cognitive psychology and attention theory hints at significant advantages of employing the auditory modality for the peripheral perception of information, the use of sound for the design of ambient displays has been largely neglected so far, which is why we have deliberately explored this approach in our research, including the use of _blended sonification_, where existing environmental sounds are used as the basis for auditory representations of information.<br />

In our practical work, we have developed four ambient displays as research vehicles, which cover three distinct settings in order to additionally evaluate the influence of an ambient display's context of use: The _InfoPlant_ is a “living” interface, which we used in a longitudinal study to give feedback on the test subjects' electricity consumption in their apartments. Although we could indeed observe a reduction in consumption, this was only the case for appliances within sight of the feedback display and highly dependent on the users' initial motivation and interest. The _Sonic Shower_ gives auditory feedback on the energy and water consumption while taking a shower, and in an online survey we found that our two blended sonifications were perceived as significantly less intrusive than for example a speech-based design. The _EcoSonic system_ supports users in driving in a more fuel (or energy) efficient way, and in our study we could observe that our two types of auditory feedback led to a significant reduction of consumption as well as a reduced number of glances at the visual consumption display. Finally, the _Slowification system_ provides feedback about the current vehicle speed in consideration of prescribed speed limits and common driving practices based on spatial panning of the car's audio system's sound signal, and in our study, employing a virtual reality driving simulator, we found that speed limits were adhered to significantly better and also observed less deviations from the traffic lane.<br />

As can be seen from the individual results, the use of sound can indeed be highly advantageous for ambient displays, as it does not occupy the visual perceptual channel, which is predominantly used for primary activities. Furthermore, it allows for a higher variability in the context of use, which is also of particular importance for the design of ambient displays in general, as it influences the effectiveness of the peripheral information conveyance. Finally, incorporating, or even building on, existing sensory stimuli, as is done for blended sonifications, has shown to contribute to enhancing the unobtrusiveness of ambient displays.