2014 – 2017   |   Part of my PhD research

In this four-year PhD research, I have been investigating how people interact with lighting systems that are shared in use. In recent years, lighting systems have started appearing that offer personal control over the lighting to their users; both for the home and for the office environment. Although personal control over lighting has proven benefits, its seems that genuine personal control is an illusion. Since most of our environments are shared in use, the lighting becomes shared as well: interaction by one actor can easily impact other people. In this research, we have contributed to a better understanding of how people interact with lighting systems that are shared in use. We have used this understanding to reflect upon how to design lighting interfaces that better support people in their coordination of shared lighting use.

Investigating Lighting Conflicts in the Home Environment

We studied everyday lighting conflicts in the home environment, in two complementary studies. In the first study, we used a combination of probes and dyadic interviews to identify real-life lighting conflicts between couples living in single-room apartments. The results highlight how people take each other into consideration during shared use of lighting, avoid manifestation of conflict, and easily compromise. We also identify three seemingly common causes of conflict, resulting from differences in preference, activity, or attitude. Resolution of these conflicts seems to largely rely on pre-established agreements, made as early as when purchasing the luminaires.

the probe booklets from the conflict study The probe booklets from the first study on lighting conflicts. By comparing the answers from the partners in the dyadic interviews, we were able to identify causes of lighting conflicts.

Since we found that lighting conflicts are rare and often do not manifest themselves, we took a more disruptive approach in the second study. By implementing a lighting system in family living rooms in which a lighting change would always affect the whole room at once, we aimed to provoke conflicts in order to study conflict resolution strategies. The results show that people mostly seem to apply conflict-avoiding and accommodating conflict resolution strategies. If there is a risk that others are negatively affected by an adjustment, people rather not interact with the system at all.

the technology probe in study 2 The lighting system and probe booklets that were used in study 2 to disrupt normal lighting use.

The two studies show that rather than avoiding conflicts, interfaces should be designed in such a way that they give people the confidence to interact in a shared situation. We expect that interfaces can do so by providing people with the right information at the right moment, so that people can make a more informed decision. This insight has lead to a focus on design for awareness in the later phases of my PhD.

The two studies are described and discussed in more detail in a paper that has been published in Personal and Ubiquitous Computing.

Shared Lighting Use in Open-plan Offices

We continued with a longitudinal investigation of how people coordinate sharing of lighting system in an open plan office. Compared to the home, in open-plan offices a larger space is shared more flexibly amongst a more varied group of co-workers. Therefore, needs, wishes, activities, use of space, and group dynamics vary between people and over time. Moreover, since we introduced three new interfaces in this study and a new lighting system, and since relationships are not as tight as in the home, it likely that shared use has not yet settled into established norms and routines.

We designed three interfaces that systematically vary in their interaction style and the type of information they represent: the Floorplan, the Pointer, and the Canvas interface. The interfaces were deployed long-term and in a real open plan office. We used the interview data – consisting of detailed qualitative descriptions of people’s interactions with the system – in three different analyses.

Three lighting interfaces The Canvas, Pointer, and Floorplan interfaces.

In the first analysis, we looked at how people appraised and understood the interfaces as a way to control the lighting. The findings show relations between interfaces characteristics such that having an interface on a personal multi-purpose device or on a central interface solely dedicated to lighting, influences whether people make individual or more collective lighting adjustments and decisions. We find similar relations between distribution and interaction sequence and the perceived effort interaction takes, and between the interaction modality and engagement. These insights have been been presented at DIS2017.

In the second analysis, we further deepen our understanding of how differences between the three interfaces influence the social dynamics surrounding their interactions. We found that interface characteristics like distribution, ownership, and modality affect the amount of verbal communication during interaction, the extent to which people take each other into consideration, and the perceived level of accountability. These relations emphasize the importance of considering shared use when designing interfaces for everyday systems. The analysis has been explained in more detail in a paper presented at CHI2018.

In the third analysis, we did not look at the differences between the interfaces. Instead, we used all the interactions with the system to investigate how people make decisions while interacting with a system that is shared in use. We identify three common considerations that people had when deciding on how to interact: people considered their reasons to interact, the expected impact on others, and how to balance one’s own concerns and the concerns of others. That two out of these three considerations concern other people indicates that people perceive the system as shared and take others into account in their interactions. We used these insights to build a model of interaction with shared systems: the exploration-action model, which is currently under review.  


Last update: March 2018
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