By Bernt Meerbeek, Philips Lighting Research, The Netherlands

People have a deeply rooted need to experience control. Today we are surrounded by intelligent systems that take decisions and perform actions for us. This can make life easier, but there is a risk that users experience less control and reject the system. The central question in this thesis is whether we can design intelligent systems that have a degree of autonomy, while users maintain a sense of control. We try to achieve this by adding an ‘expressive interface’: the part of a system that provides information to the user about the internal state, intentions and actions of the system. We examine this question both in the home and the work environment.

In the workplace, we have focused on automated blinds systems. For 20 weeks, we have monitored the use of automated blinds in 40 offices and studied the user experience. Over 75% of users switched off the automatic mode permanently. This shows that users are not satisfied with the automatic behavior and want to operate the system themselves. However, this leads to less energy savings in a building than expected. Simulation results indicate that offices in which the automatic mode is deactivated consume on average about three times more energy for heating and cooling than offices in which the automatic mode is active. We therefore propose to improve the acceptance of automated blinds by making users aware of how the system works and how its use affects energy consumption. We designed an expressive interface for the automatic blinds consisting of a light feedback device that informs users about the current daylight conditions and the upcoming or recommended blinds adjustments. We have mounted the expressive interface to a virtual window with automatic blinds and tested the system in two user experiments. The results show that the addition of an expressive interface enhances the users’ satisfaction. Additionally, users made fewer corrections after an automatic adjustment of the blinds and they followed the suggestions of the system more often than with the system that had no expressive interface.


This thesis shows the potential of the expressive interface as an instrument to help users understand what is going on inside the system and to experience control. The expressive interface might be essential for the successful adoption of the intelligent systems of the future.

On July 5th 2016, Bernt Meerbeek defended this thesis Cum Laude at the Eindhoven University of Technology. The thesis can be downloaded at: