In this paper, a novel means of status display in mobile phones is discussed: A permanent tactile heartbeat-like pulsation of the phone. In the study presented, this pulse was used to let the phone continuously communicate a calm state of 'Everything is okay.' - then, this pulse was suddenly interrupted, as soon as the phone needed the user's attention. We hypothesized that the users would instantly notice the missing pulse. The participants in our study wore the phone for one day and were interviewed afterwards. Also, a log file about the events and user responses was kept on the phone. The results suggest that the proposed system is not sufficient as a means of notification; only 55% of the events were noticed within the first minute. While some users were simply annoyed by the pulse, others did like the reassurance that the phone was 'present and calm', but 'easy to ignore' at the same time. These results indicate that the system might be eligible as an ambient status display for mobile phones.
ACM Classification Keywords H5.1. Information interfaces and presentation INTRODUCTION When carrying a mobile phone, the state of ‘not ringing’ is currently ambiguous: It might mean that nothing happened, that a call was missed (Fig. 1a), that the phone is off or that it is simply not there. Mobile phones do not employ a clearly distinguishable state of ‘I’m here, and everything is fine.’.
Regardless of where and how the phone is worn, mobile
phone users are bound to miss calls sometimes [
In on-the-go interaction, the audiovisual senses are often busy, or simply not applicable as a channel of interaction, and so utilizing the modality of touch is promising: Tactility and proprioception have come to special attention in mobile interaction design.
RELATED WORK
Existing research has investigated different ways of
vibrotactile, surface- and shape-based information design
for mobile devices: Brewster, Brown et al. proposed
Tactons [
Some existing mobile phones ([
Other recently released mobile phones [
Investigating a system based on patterns that we understand
inherently, and cognitively effortless, might be worthwhile,
especially in the age of distraction, interruption and
information overload [
The concept of a ‘living’ mobile phone is based on the
hypothesis that as social beings, we are inherently able to
interpret signs of life. For example, psychological research
has shown that children are able to categorize living and
non-living objects already in early phases of their
development [
The difference of this study to its predecessor [
The users were encouraged to keep a diary of their activities while carrying the phone, with special regard to situations in which using the functionality would be different than in others (e.g. in a library, as opposed to at a concert). RESULTS The users reported that the suitability of the functionality as a means of notification depended on the strength of the vibration and the situation they were in – sometimes, they would just miss it when it is not strong enough. At the same time, the stronger the vibration was, the more annoying they found it. Most users stated that they were able to ignore the pulse at low intensities, and shift their attention to it to check it ‘on demand’. At higher intensities, the system was mostly found to be “very annoying”. Users reported that they were well able to perceive the pulse while sitting in a calm environment, and were hence able to react to its sudden end. While walking, they were not able to feel the pulse, and had to ‘check’ for it by grasping the phone through or in the pocket.
Some users particularly enjoyed that either ‘everything was fine’, or, be it ‘because of a missed event’ or ‘because I did not wear it close enough’, it required them to do something. Silence, in this system, is never good.
Users stated that they found it difficult to immediately react to the death of the phone and that they often had the feeling of being ‘too late’. They also reported an ‘inverted phantom vibration’, in which they thought the phone had stopped beating, but it had not. Overall, the users felt that they were not really good reacting to the stopped pulse, and estimated the average common time to be about five minutes. They reported that when they checked their phone, which was often ‘accidentally’, that it was often dead already, presumably for a longer time.
The log files revealed the actual reaction times (to a total number of 194 events): 19% of the responses occurred within the first 10 seconds, 44% within the first 30 seconds. 55% of the responses to a stopped beat occurred in the first minute after the event (Fig. 2). After 10 minutes, 90% of the events were confirmed.
DISCUSSION Many users in our test group were quickly annoyed by the pulse, only few got used to it. Similar to the previous study, the pulse was found to be more annoying in silent situations, while it was rated ‘easily ignorable’ and ‘helpful’ in busy situations.
The permanent tactile stimulation that the system produced was helpful for the users to be aware of their tactile contact to the device. For people in special user groups (e.g., emergency doctors or security staff) that have to be permanently sure that their network reception, battery status, etc. are fine, that they have no calls missed, and that they have not lost tactile contact with the device, such a ongoing reassurance could be helpful.
A result of only 19% recognition rate within the first 10 seconds and 55% within the first minute is not sufficient for a notification system. Instead, it seems more plausible to use the system as a permanent status display.
Even though the task ‘When the heartbeat stops, press the
center button to reanimate it.’ was plausible to the users,
they did not state that they treated or perceived the phone as
a pet: While the metaphor of the ‘living phone’ was clear, it
is still uncertain if a non-lifelike stimulation would have
produced different results.
Interestingly, the users stated that they ‘just accidentally’
looked at the phone when they discovered that the pulse had
stopped. It is, however, unlikely that every user accidentally
checked the phone every minute. What might be possible
instead is that they took notice of the stopped pulse
subconsciously. It has been argued before that some
decisions are largely based on external subconscious cues,
even though they feel like free will [
Permanent life-like tactile actuation as we propose it should be looked at critically: We do not know the bodily and psychological consequences of a continuous external heartbeat – nonetheless, we think that it is a worthwhile undertaking to study it.
CONCLUSION This research cannot answer the question of whether permanent information should be preferred over permanent checking. Still, a status display like the one proposed might be suitable for users that need permanent reassurance about their phone’s status.
People that show addictive behavior to their mobile phones should also be taken into consideration. The permanent stimulation might satisfy their need to be in touch with the phone, but in terms of addiction, it might make things worse.
This study contributes to the ongoing research in tactile mobile interaction design. The proposed system cannot replace traditional notification and status display systems, but investigating permanent systems is worthwhile: How can users be comfortably informed, and should this information occur in bursts, or in a stream? FUTURE WORK Most of the subjects in this study asked for an inverted principle: Silence, when nothing has happened – and a subtle, yet perceivable pulse after a missed event. This will be investigated in a future study.
Clearly, a long term study is needed, that examines the costs and benefits of permanent tactile actuation in mobile phones. What needs to be investigated as well is whether life-like movements are indeed more suitable in the proposed case than non-life-like movements. In this context, it would also be important to find out how the relationship to the device changes when it behaves like a living being.
It could also be thought of externalizing the actuator from the phone: Users that do not maintain body contact with their phone (e.g. when wearing it in a bag) would probably prefer an externalized version.
Ultimately, this project aims to create a ‘gut feeling’ for the phone; Users should not have to think about checking their phones. Until that point is reached, we face the ambiguity of silence in mobile phones: No news is no news.