H9 Closed Loop *

The WorldBeat exhibit includes features to find tunes by humming, improvise to a band, play virtual instruments, guess instrument sounds, and others, many of them with several subsections to explore and try out. It would take about an hour to work through all of its functions; this is far more time than the average user wants (and is expected) to spend with the system. To make sure that every visitor still experiences a gratifying interaction, those features are offered as alternative choices from a central selection page, which is always just two clicks away from anywhere in the exhibit structure. Upon entering one of those features, its message is explained very briefly, and after trying it out, the user is lead back to the central selection page, which he usually already knows. At this point, a user can easily leave the system, or pass on to the next waiting visitor, with a feeling of closedness because he knows that he has at least explored that feature now.

The same principle applies to standard computer applications: Shneiderman [1998, p. 75], in his Eight Golden Rules of interface design, includes a recommendation to "design dialogs to yield closure": Action sequences should have an obvious beginning, middle, and end, with clear feedback about the completion of such a sequence to convey the sense of accomplishment to the user.