Activity Tracking in vivo.

While recent research has emphasized the importance of understanding the lived experience of personal tracking, very little is known about the everyday coordination between tracker use and the surrounding environment. We combine behavioral data from trackers with video recordings from wearable cameras, in an attempt to understand how usage unfolds in daily life and how it is shaped by the context of use. We recorded twelve participants' daily use of activity trackers, collecting and analyzing 244 incidents where activity trackers were used. Among our findings, tracker use was strongly driven by reflection and learning-in action, contrasting the traditional view that learning is one of deep exploration, following the collection of data on behaviors. We leverage on these insights and propose three directions for the design of activity trackers: facilitating learning through glances, providing normative feedback and facilitating micro-plans.