Interactional trajectories

Posted on May 12, 2009


Steve Benford's Trajectories at CHI09 I like the work of Steve Benford.  While his paper (From interaction to trajectories: designing coherent journeys through user experiences ACM DL) at  CHI was primarily concerned with interaction design, I think that we can see a wider application, particularly into education for sustainability.  

Instead of one-off functions,  Benford considers interactions as a continuty of experiece – as journeys.  This leads to the realisations that interactions can be interwoven, steered and captured.   Each of us is also having multiple continuous trajectories:

While these journeys may pass through different places, times, roles and interfaces as we discuss below, they maintain an overall sense of coherence; of being part of a connected whole. These journeys are steered by the participants, but are also shaped by narratives that are embedded into spatial, temporal and performative structures by authors. They are also influenced by the dynamic process of orchestration … Finally, they may be undertaken by groups and/or involve encounters among participants.

These trajectories can be plotted in terms of space,  interfaces 
(“through local ecologies of interfaces”), time, and roles  (and by my extension to learning and understanding).    The key is that these trajectories are far from continuous.  There are key moments of transition at which continuity might be at risk.

Beginnings frame an experience, through attracting attention, admission, briefing and handing over equipment as part of the framing of the experience.

Endings use souvenirs and replay interfaces to support reflection, discussion and sharing memories.

Role transitions and interface transitions also involve handing over equipment and further briefings.

Traversals between physical and virtual worlds are enhanced by matching physical and virtual design and through traversable interfaces.

Temporal transitions between episodes involve periods of disengagement and subsequent reengagement and require succinct summaries of missed action.

Transitions into physical resources that cannot easily be reproduced must deal with contention, while transitions across seams must deal with limitations in the underlying technical infrastructure.
The authors argue that trajectories should be managed.  This is a balance between the participant and the artist/author,  which is refered to as orchestration. 

Thus, there is a fundamental tension between an author’s ideal trajectory that is designed into an experience and a participant’s actual trajectory, with orchestration being required to resolve the two, enabling participants to temporarily diverge from and reconverge with the preestablished path.

The role of shared trajectories:

We can express the nature of collaboration in multi-user experiences by considering how multiple participants’ trajectories interweave with one another. As continuous threads, trajectories might approach, cross and leave one another multiple times. As they approach, so participants should become increasingly aware of one another, be able to communicate, and affect each other’s experience.

There are also good reasons for steering trajectories apart, physical constraints but also to minimise distractions and interruptions.