Sharing mobile device context: a comparison between Bluetooth and NFC

Kostakos, V., O'Neill, E., Shahi, A. (2006). Building Common Ground for Face to Face Interactions by Sharing Mobile Device Context. Workshop on Location and Context Awareness (LOCA 2006), Dublin, Ireland. Lecture Notes in Computer Science 3987, Springer, pp. 222-238. In this paper, the authors relies on Herbert Clark's theory of "grounding" (the construction of a shared understanding of the situation during collaboration) through a mobile application that allows users securely to exchange the contents of their address books (through Bluetooth and NFC).

The most important basis for the construction of common ground, evidence of common membership of cultural communities, is often difficult to establish. (...) Our application uses Bluetooth, NFC and mobile device address books as a means of locally sharing context. (...) We utilise users’ address books as the source of context. Using our application, two users are made aware of the common entries in their address books. (...) [The scenario:] Alice and Bob exchange digests of their address books. They then compare the received digests with their local digests to identify matches. Alice is then shown her local information linked to the matches, and so is Bob. The displayed information is not necessarily identical.

The technological affordance is quite interesting too:

With Bluetooth, two people can use our application without having established prior physical communication (in the form of eye contact, body language, or verbal communication). On the other hand, the use of NFC requires that the users and devices enter each other’s “intimate zones”. (...) the different ranges of Bluetooth and NFC create two different models of interaction between the users. Using Bluetooth, users need verbally to negotiate and coordinate their efforts to exchange data. With NFC, users have the cue of physically touching their phones. This tangible interaction is an explicit action which synchronises both the data exchange between devices and the coordination process between the users.

The user study is quite simple () and gave intriguing results concerning the Bluetooth/NFC differences: especially the fact that users preferred NFC over BT. Here are some of the lessons drawn from this study

Bluetooth Could be useful for getting to meet strangers Users reluctant to respond to requests from unknowns Does not give away physical location of user Weak joint experience Request - reply model
Limited usability when using the phone Participants initially thought the system would exchange numbers Preferred for face to face interaction Strong joint experience Symmetric model

Why do I blog this? this connects to the fact that I also use Clark's framework; relations between technology/media and the establishment of a common ground are then of interest to me. I also liked the comparison between the 2 technologies (NFC/BT) and I would be happy to see a broader field study with a more ecological context (namely real contacts).