H1 Attract-Engage-Deliver *

The user profile of an interactive exhibit is usually very broad, and users generally have no strong need to use such a system. This means that the initial interest to use such a system must be motivated by the system itself.

Most interactive exhibits are not just for entertainment. Their goal is deliver a "message" - to explain some facts, concepts, or ideas - to the user, through the interaction. Therefore, it is important, after the initial attraction, to keep the user occupied until this message can be delivered.

But once this goal has been achieved, it is important to allow the user to end the session in a planned and positive way. Users generally should not break off in the middle of an interaction because they have become bored, or because they do not know when they will be able to leave the system orderly.

For example, in the Exploratorium, a children's technology discoverymuseum in San Francisco, each exhibit is labelled with a three-sentence description of the following form:

To do and notice: This part explains briefly what to do with the exhibit, which buttons to push or levers to move, and what to look for in the system reaction. For example, an exhibit on glass fibres would tell the user to press a button to light a lamp, and to observe how the light comes out of the end of a bent glass fibre.

What's going on?: The second sentence summarizes what is happening in the system. In the example, it would explain how the light is reflected by the inside of the glass fibre wall.

So What?: The last sentence, probably most important, tells the visitor why this phenomenon is important. In the example, it would explain how glass fibre cables can be used to transmit information very quickly.

These descriptions actually make the attraction, engaging, and delivering phases of the interaction with an exhibit explicit.

Similarly, the WorldBeat system wants to convey an overall message: that computers open up new ways to interact with music. Each of the various sub-functions of the system shows a more specific example of this general message: how computers can help with conducting, improvising, finding music, etc. The system initially attracts visitors with an interesting yet simple interface that quickly leads to a main selection display of those features. Each feature in turn briefly and explicitly explains what its "message" is. When the user has explored one of those features, he has taken its specific message with him, and is returned to the main selection page where he can continue exploring the system, or leave the exhibit in a consistent and satisfying way. Nobody explores the system completely; this would also take much longer than the interaction duration as planned by the exhibition centre. Instead, most users explore only a few of the features, but still take the messages from those features with them.