Getting a Grip on Tangible Interaction:

A Framework on Physical Space and Social Interaction

Eva Hornecker and Jacob Huur (2006)

This article explains the huge potential of tangible computing. Unlike the traditional personal computing approach where the main interaction is based on the use of a computer monitor as data output device, and keyboard with a mouse for data input, tangible computing relies on an embodied interaction. This new approach understands the importance of manipulating physical objects as an effective fashion for interacting with a computational system. Tangible computing does not only allow the user for a more natural interaction but it also expands the possibilities for social and collaborative action.  

Tangible user interface (TUI) has had big relevance in the development of human-computer interaction (HCI) in the last decade. For over 30 years have the users been able to just see the digital data through a computer monitor in the same fashion we look through a window. TUI offers the possibility of of interacting with the digital world by manipulating physical objects, being a computer monitor in many cases completely unnecessary. Designing tangible interfaces implies not just designing the digital interface, but also the physical and the interrelation with one another. 

The authors describe four main approaches within TUI:

1.  Tangible manipulation: making a material representation of digital elements in order to control them.
2. Spatial interaction: since the tangible interaction takes place in a three dimensional space then the interaction takes place in form of spatial movement. 
3. Embodied facilitation: it refers to the effects over behavior depending on the configuration of material objects and space.
4. Expressive representation: it focuses on the representation of both physical and digital elements and how understandable are these representations. 

The authors finalize by concluding that each one of these items have different level of importance depending on the application's area where it is being utilized. Regardless which area, the potential of tangible computing is enormous.