Chapter One. Background

1-1 Interface Definition

Call our USA number above and test your stamina against the incredible frustration provided by our voice mail system.

?span class="docEmphasis">Note at the bottom of an advertisement for Simple-brand shoes

In this book, I usually shorten human-machine interface or human-computer interface to user interface or simply interface . Many people assume that the term user interface refers specifically to today's graphical user interfaces (GUIs), complete with windows and mouse-driven menus . For example, an article in Mobile Office magazine said, "Before too long, you may not have to worry about an interface at all: You may find yourself simply speaking to your computer." As I pointed out in response, a voice-controlled system may have no windows, but neither do telephone voice-response systems, and they often have hellaciously bad interfaces. The way that you accomplish tasks with a product—what you do and how it responds—that's the interface. (See also Raskin 1993.)

1-2 Keep the Simple Simple

Technology is a queer thing. It brings you great gifts with one hand, and it stabs you in the back with the other.

?span class="docEmphasis">C.P. Snow (quoted in Jarman 1992)

Despite a burgeoning population of interface designers, few consumers claim that new products, such as an electric, four-button wristwatch, are easier to use than they were a few decades ago. If you point out to me that watches , like computers, now have much greater functionality (true) and that, in consequence, the interfaces have had to become more complex (debatable), I respond by pointing out that even the simple tasks that I used to do easily have become mired in complexity. Complex tasks may require complex interfaces, but that is no excuse for complicating simple tasks. Compare the difficulty of setting the time on your electronic, four-button wristwatch to that of completing the same task on a mechanical model. No matter how complex the overall system, there is no excuse for not keeping simple tasks simple.

Of the many absurdities foisted on us by inept interface design, perhaps it is the complication of what should be simple that gives comic strips and comedians the most opportunities. In the movie City Slickers , three chums are driving a herd of cattle. Billy Crystal's character tries unsuccessfully—apparently for hours—to explain how to use a VCR to record a show on one channel while watching another. When the friends finally explode in exasperation at the lengthy explanation, Crystal's character cheerfully agrees to drop the subject and offers instead an explanation of how to set the clock on the VCR. This offer enrages his cronies and cracks up the audience. The humor arises from the dissonance between the simplicity of the task and the difficulty of the interface: If the vertical front of a VCR had labeled buttons situated above and below the digits of a clock as shown in Figure 1.1, fewpeople would have any trouble setting the clock.