Physical Affordances Considered Harmful ! ?

Frequently physical affordances are considered one of the main advantages of tangible interfaces or input devices, making interaction intuitive. This assumption may be overly simplistic – because physical objects have a multitude of physical affordances and properties, it is difficult for the designer to restrict these to (only) those that match with the digital system that they are connected with. This paper presents examples from a user study of children interacting with augmented books using physical paddles. These illustrate how children expected the digital augmentations to have physical 3D-behavior, encouraged by the possibility to interact in 3D space and by the (digital) visual feedback. The affordances of the physical interaction devices were rather deceiving, being a mismatch with the digital system’s capabilities, and in effect intuitiveness of interaction broke down. Finally, a first cut at an analysis is presented of what our observations mean for the intuitiveness of tangible input elements and the use/virtue of physical affordances.