ABSTRACT
The computing literature often draws an artificial distinction between input and output; computer scientists are used to regarding a screen as a passive output device and a mouse as a pure input device. However, nearly all examples of human-computer interaction require both input and output to do anything useful.
For example, what good would a mouse be without the corresponding feedback embodied by the cursor on the screen, as well as the sound and feel of the buttons when they are clicked? The distinction between output devices and input devices becomes even more blurred in the real world. A sheet of paper can be used both to record ideas (input) and to display them (output). Clay reacts to the sculptor’s fingers, yet it also provides feedback through the curvature and texture of its surface. Indeed, the complete and seamless integration of input and output is becoming a common research theme in advanced computer interfaces, such as ubiquitous computing [Weiser, 1991] and tangible interaction [Ishii and Ullmer, 1997].
