The Do Not Disturb Challenge (CHI ’15)

Do Not Disturb Mode

Notifications are alerts intended to draw attention to new online content. Traditionally used in text messaging, email clients and desktop instant messengers, notifications are becoming used by all types of applications across all types of computing devices.

Today in 2015, we are still living in the ‘wild-west land-grab phase’ of notifications: more and more OSes introduce notification centers and more and more apps generate notifications. However, little is known about how the increasing number of notifications affect us.

Hence, in a collaboration between the Scientific Group of Telefonica R&D and Human-Computer Interaction Institute at Carnegie Mellon University, Luz Rello and I envisioned the Do Not Disturb Challenge. As part of challenge, participants disable notifications on their phones, tablets, and computers for a full day.

In December 2014, we rolled out a pilot of the Do Not Disturb Challenge with 12 participants. While participants reacted wildly different to the lack of notifications, for many, it was a strong experience.

The hugest impact was social. People have come to expect timely responses to their messages. Without notifications, many participants felt no longer able to meet these expectations. Some were informing others before the study that they would be less responsive, some kept constantly checking the phone.

At the same time, many participants noted that without the constant interruptions by notifications, they felt more focus, relaxed, and productive. Others realised that not all notifications are the same and deserve the same treatment. For example, many participants felt relieved by the absence of group-chat notifications.

Probably the main take-away so far is that people have very strong and polarized opinions towards (missing) notification alerts. The only consistent findings across the participants was that none of them would keep notifications disabled altogether. Notifications may affect people negatively, but they are essential: can’t live with them, can’t live without them.

The results will be presented at CHI ’15: the ACM Conference on Human Factors in Computing Systems (CHI) to be held from April 18 – 23 in Seoul, South Korea.

Martin Pielot and Luz Rello
The Do Not Disturb Challenge – A Day Without Notifications
CHI EA ’15: Extended abstracts on Human factors in Computing Systems, 2015.

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Ambient Timer – Unobtrusively Reminding Users of Upcoming Tasks with Ambient Light

Alice is working on a report for the head of her department. At the same time, there is a meeting scheduled in thirty minutes, which she has to attend. The Ambient Timer is already illuminating the wall behind her monitor in a low-attention state, so Alice feels confident that she will be reminded of the meeting. A few minutes before the meeting, the status of the ambient light display has changed to a more salient, intense output. While she is still working on her report, she slowly becomes aware of the nearing deadline and starts finishing the paragraph she is currently working on. One minute before the meeting the light has become so salient that it is hard to ignore. Alice stores the document on the server, puts her computer into sleep mode, and arrives at the meeting on time.


A timer that uses ambient light

The Ambient Timer is a research prototype developed in the Interactive Systems Group of the OFFIS Institute for Information Technology. Its goal is to gently remind information workers about upcoming events. such as illustrated in the scenario above. It uses LED glued to the back of the monitor to illuminate the wall in the peripheral field of vision of the worker.

User Study

With this prototype, we conducted a user study in collaboration with the HCI and Mobile Computing Group of Telefónica Research. We experimentally studied two instances of the Ambient Timer:

  • expo: a gradual change from green to red, becoming exponentially faster, and
  • sinus: a sinusoidal change between red and green which became increasingly faster.

We compared these reminders against two traditional techniques to keep track of appointments:

  • a clock, such as the one in the corner of your computer screen, and
  • a popup alarm, such as when you use Outlook, Lotus Notes, or the OS X Calendar for your appointments.

For the study, we asked participants to copy and correct texts. Meanwhile, a 10-minute timer was running in the background. The task was to finish as many texts as possible in 10 minutes, but without “overshooting”, i.e. having an unfinished text after 10 minutes. In the expo, sinus, and clock conditions, the remaining time was presented by the Ambient Timer or a clock, respectively. In the popup condition, no time was given, but a popup informed the participants 30 seconds before the end of the time limit.

The experiment used a repeated-measures design, i.e. each participant tested each of the four reminder systems in counter-balanced order.


Our results show that participants experienced significantly fewer interruptions when using Ambient Timer in the expo condition, i.e. with an exponential change from green to red, compared to all other reminder techniques in our experiment. Their average typing speed was significantly faster when in this condition, too. Participants ranked this design best, felt most confident using it and preferred it over all other techniques.


This experiment shows that using light in the periphery around the monitor is a great way to provide information workers with information in an ambient way. Used as Ambient Reminder, ambient light might help to structure typical office work, which is often a mix of concentrated desktop work and scheduled meetings and appointments. It allows office worker to avoid to constantly check the clock or be interrupted by alarming popups interrupt.


The details of the experiment have been published in the 14th IFIP TC13 Conference on Human-Computer Interaction, held in September 2013 in Cape Town, South Africa:

Heiko Müller, Anastasia Kazakova, Martin Pielot, Wilko Heuten and Susanne Boll.
Ambient Reminder: Unobtrusively Reminding Users of Upcoming Tasks with Ambient Light.
INTERACT ’13: 14th IFIP TC13 Conference on Human-Computer Interaction, 2013.

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