In this project with Jörg Müller we investigated in a lab and a field study how passers-by notice the interactivity of public displays. We designed an interactive installation that uses visual feedback to the incidental movements of passers-by to communicate its interactivity.

The lab study reveals: (1) Mirrored user silhouettes and images are more effective than avatar-like representations. (2) It takes time to notice the interactivity (approx. 1.2s).

In the field study, three displays were installed during three weeks in shop windows, and data about 807 persons interacting were collected. Our observations show: (1) Significantly more passers-by interact when immediately showing the mirrored user image (+90%) or silhouette (+47%) compared to a traditional attract sequence with call-to-action. (2) Passers-by often notice interactivity late and have to walk back to interact (the landing effect). (3) If somebody is already interacting, others begin interaction behind the ones already interacting, forming multiple rows. Our findings can be used to design public display applications and shop windows that more effectively communicate interactivity to passers-by.

Results of this project were published at CHI 2012. The paper received a Best Paper Award: