Exploring the Relations between Physical Objects and Digital World with a Geometric Sorting Board

Tangible user interfaces (TUI) have gained popularity in the last few years, at the end of a process where the computer devices - especially in those contexts that are not related to the working activities - have lost deputed spaces and trained operators for mixing with the everyday activities of the casual users. TUI are appealing for many users because they promise to control and to access easily the state of digital systems without requiring a specialized environment or a long training for users. In spite of that, while in the last years different implementations have been realized and a number of frameworks have been proposed for guiding the design of TUI, most of the work done so far has not completely exploited the role of the shape of physical objects. This paper is part of a research work aimed at examining the potential of the morphology of the physical artifacts, for building meaningful mappings between physical artifacts and digital functions. In particular in our research we focus on examining the relations between the different types of surfaces that define an object and the different types of digital functions, discrete and continuous. While in our previous research we introduced a set of guidelines defining a specific mapping between the physical objects and the digital functions and we asked the users to evaluate them, in this work we involved them in the design phase for defining the mapping between a predefined set of physical objects and digital functions. The aim was twofold. On one side we considered our test as an educational activity, for improving the awareness of users (i.e., in this case they were also perspective interface designers) that all the interfaces, including TUI, are not natural but are the result of a design activity that may lead to good or bad results. On the other side we wanted to verify, in a situation characterized by scarcity of physical and digital resources, which physical and digital cues were considered as stronger by the users for specifying the mapping. While the exam of the behavior of the majority of the users confirmed the findings of our previous work, the test revealed also other behaviors triggered by the exploitation of other cues