Increasing collocated people's awareness of the mobile user's activities: A field trial of social displays

Many activities that have traditionally been performed with different dedicated physical artifacts are now done with personal mobile devices. Consequently, the privacy of mobile interfaces has hampered social observability and chances for serendipitous interactions. For example, reading an electronic newspaper with a mobile device does not allow the surrounding people to be similarly aware of the reader's activity as traditional newspapers. Social displays are additional displays on mobile devices providing the surrounding people with light-weight cues about the activities of the device user. We implemented a prototype that reveals the user's current active application and presents its name on an e-ink display on the backside of a mobile device. We conducted a ten-day field trial with 13 participants using the prototype. The results show that the prototype was able to increase awareness of users' mobile activities and occasionally triggered interactions with others, without significantly violating the sense of privacy.