Here is a good model for a successful interface, please excuse the poor quality photograph. I took my daughter out yesterday to try on some hats and naturally no trip to the childrens clothing section is complete with out her going and playing with the toys on the same floor. Catriona found this simple looking “bike” and within 30 seconds was zooming around kniping at the heels of the other store patrons. I was struck by the ease in which she was able to use this toy and despite my belief that she is near genius I have to believe that the construction of the toy itself had quite allot to do with her ease in using the bike’s “interface”.
The bike moves around without pedals by a simple rocking of the handle bars. This action creates momentum, allowing you to acquire speed, after which you are able to glide. For an old man like myself it’s pretty ingenious.
This device succeeds in ways that can be applied to other more “traditional” interfaces.

• All the complexity is hidden (there is a gear and extra wheel underneath).
• The interface that controls the motion is attached to an object that allows for natural interaction. Catriona expects to move the wheel, it’s her mental model of this device, so she naturally wants to play with the steering wheel. This allows her to discover how the interface works and because she has done it many times before the time to learn this device is greatly reduced.

Pretty cool. An additional feature that I didn’t try out was the “bikes” ability to scale. The sales lady said that it accommodate even people of my weight and size. She motioned with a smile for me to hop on. I declined the opportunity.