Designing Gestural Interfaces

Chapter 2. Designing for the Human Body

"Hands are underrated. Eyes are in charge, mind gets all the study, and heads do all the talking. Hands type letters, push mice around, and grip steering wheels, so they are not idle, just underemployed."

—Malcolm McCullough, Abstracting Craft

The best interactive gestures are those that combine the correct sensors (for detecting motion) with a human movement to deeply engage in an activity. But what is the range of human movement, and how do we move? Few designers or developers, unless they are trained as industrial designers or create medical devices or exercise equipment, have done much study of the human body. Typography, yes; anatomy, no. Until now.

Before delving into this chapter, go to a public space such as a park or restaurant and watch how people move, gesture, and interact. You'll notice that the range of human movement is fairly broad, thanks to the variety of limbs we have and especially to the dexterity of our hands. But you'll also see patterns emerge, along with a fairly standard lexicon of gestures and movements, and that is what this chapter examines and the book's appendix begins to catalog.

BASIC KINESIOLOGY

To apply the correct gesture to the correct action, it's helpful to understand a little about how the human body moves. The body is, after all, the primary input device for any gestural interface, and designers and developers should know the basics of its system, just as they understand (at least) the basics of computer ...