About Face 2.0(c) The Essentials of Interaction Design

Chapter 21: Direct Manipulation and Pointing Devices

Chapter 22: Selection

Chapter 23: Drag and Drop

Chapter 24: Manipulating Controls, Objects, and Connections

The scientists who invented computers gave us the complex symbology of language as the tool for communicating with software. It has the advantage of precision, but it is far too labor-intensive and error-prone. Pundits outside of the industry—and some inside it who should know better—advocate instead an interface based on speaking to our computers. Words, however—especially spoken words—are prone to misinterpretation and quotation out of context. Communication by demonstration is far less ambiguous. The idea of pointing with a mouse or stylus or finger follows this concept. Because these actions are more direct, we show the computer (or other digital product) what to do, instead of trying to tell it what to do. The details of this paradigm have been refined over the last 25 years, and apply broadly to desktop software, as well as (with some necessary constraints) to the Web and to embedded systems. The intricate details of these interactions deserve a closer look, which this section provides.