Design of Everyday Things - Norman, Don [104]
7.2. Hook-and-Loop Fastener. With the use of hook-and-loop fasteners, the act of tying shoes is much simplified: a good example of the power of technology to change the nature of the task. But there is a cost. Children find the task so easy they gleefully untie their shoes. And these fasteners are not yet as flexible as shoelaces for the support needed for sports.
I do not want to argue for digital timepieces, but let me remind you how difficult and arbitrary the analog timepiece really is. After all, it, too, was an arbitrary imposition of a notational scheme, imposed upon the world by the early technologists. Today, because we can no longer remember the origins, we think of the analog system as necessary, virtuous, and proper. It presents a horrid, classic example of the mapping problem. Yes, the notion that time should be represented by the distance a hand moves around a circle is a good one. The problem is that we use two or three different hands moving around the same circle, each one meaning something different and operating on a different scale. Which hand is which? (Do you remember how hard it is to teach a child the difference between the little hand and the big hand, and not to confuse the second hand-which is sometimes big, sometimes little-with the minute hand or the hour hand?)
Do I exaggerate? Read what Kevin Lynch says about this in his delightful book on city planning, What time is this place?
“Telling time is a simple technical problem, but unfortunately the clock is a rather obscure perceptual device. Its first widespread use in the thirteenth century was to ring the hours for clerical devotions. The clockface which translated time into spatial alteration, came later. That form was dictated by its works, not by any principle of perception. Two (sometimes three) superimposed cycles give duplicate readings, according to angular displacement around a finely marked rim. Neither minutes nor hours nor half days correspond to the natural cycles of our bodies or the sun. And so teaching a child to read a clock is not a childish undertaking. When asked why a clock had two hands, a four-year-old replied, ‘God thought it would be a good idea.’ ”1
Aircraft designers started using meters that looked like clockfaces to represent altitude. As airplanes were able to fly higher and higher, the meters needed more hands. Guess what? Pilots made errors-serious errors. Multihanded analog altimeters have been largely abandoned in favor of digital ones because of the prevalence of reading errors. Even so, many contemporary altimeters maintain a mixed mode: information about rate and direction of altitude change is determined from a single analog hand, while precise judgments of height come from the digital display.
DON’T TAKE AWAY CONTROL
Automation has its virtues, but automation is dangerous when it takes too much control from the user. “Overautomation”—too great a degree of automation—has become a technical term in the study of automated aircraft and factories.2 One problem is that overreliance on automated equipment can eliminate a person’s ability to function without it, a prescription for disaster if, for example, one of the highly automated mechanisms of an aircraft suddenly fails. A second problem is that a system may not always do things exactly the way we would like, but we are forced to accept what happens because it is too difficult (or impossible) to change the operation. A third problem is that the person becomes a servant of the system, no longer able to control or influence what is happening. This is the essence of the assembly line: it depersonalizes the job, it takes away control, it provides, at best, a passive or third-person experience.
All tasks have several layers of control. The lowest level is the details of the operation, the nimble finger work of sewing or playing the piano, the nimble mental work of arithmetic. Higher