THE DESIGN OF EVERYDAY THINGS

THE DESIGN OF EVERYDAY THINGS THE PSYCHOPATHOLOGY OF EVERYDAY THINGS

1 * If I were placed in the cockpit of a modern jet airliner, my inability to perform well would neither surprise nor bother me. But why should I have trouble with doors and light switches, water faucets and stoves? "Doors?" I can hear the reader saying. "You have trouble opening doors?" Yes. I push doors that are meant to be pulled, pull doors that should be pushed, and walk into doors that neither pull nor push, but slide. Moreover, I see others having the same troubles-unnecessary troubles. My problems with doors have become so well known that confusing doors are often called "Norman doors." Imagine becoming famous for doors that don't work right. I'm pretty sure that's not what my parents planned for me. (Put "Norman doors" into your favorite search engine-be sure to include the quote marks: it makes for fascinating reading.)

How can such a simple thing as a door be so confusing? A door would seem to be about as simple a device as possible. There is not much you can do to a door: you can open it or shut it. Suppose you are in an office building, walking down a corridor. You come to a door. How does it open? Should you push or pull, on the left or the right? Maybe the door slides. If so, in which direction? I have seen doors that slide to the left, to the right, and even up into the ceiling.

FIGURE 1.1. Coffeepot for Masochists. The French artist Jacques Carelman in his series of books Catalogue d'objets introuvables (Catalog of unfindable objects) provides delightful examples of everyday things that are deliberately unwork- able, outrageous, or otherwise ill-formed. One of my favorite items is what he calls "coffeepot for masochists." The photograph shows a copy given to me by collegues at the University of California, San Diego. It is one of my treasured art objects. (Photograph by Aymin Shamma for the author.)

The design of the door should indicate how to work it without any need for signs, certainly without any need for trial and error.

A friend told me of the time he got trapped in the doorway of a post office in a European city. The entrance was an imposing row of six glass swinging doors, followed immediately by a second, identical row. That's a standard design: it helps reduce the airflow and thus maintain the indoor temperature of the building. There was no visible hardware: obviously the doors could swing in ei- ther direction: all a person had to do was push the side of the door and enter.

My friend pushed on one of the outer doors. It swung inward, and he entered the building. Then, before he could get to the next row of doors, he was distracted and turned around for an instant. He didn't realize it at the time, but he had moved slightly to the right. So when he came to the next door and pushed it, nothing happened. "Hmm," he thought, "must be locked." So he pushed the side of the adjacent door. Nothing. Puzzled, my friend decided to go outside again. He turned around and pushed against the side of a door. Nothing. He pushed the adjacent door. Nothing. The door he had just entered no longer worked. He turned around once more and tried the inside doors again. Nothing. Concern, then mild panic. He was trapped! Just then, a group of people on the other side of the entranceway (to my friend's right) passed eas- ily through both sets of doors. My friend hurried over to follow their path.

How could such a thing happen? A swinging door has two sides. One contains the supporting pillar and the hinge, the other is un- supported. To open the door, you must push or pull on the unsup- ported edge. If you push on the hinge side, nothing happens. In my friend's case, he was in a building where the designer aimed for beauty, not utility. No distracting lines, no visible pillars, no vis- ible hinges. So how can the ordinary user know which side to push on? While distracted, my friend had moved toward the (invisible) supporting pillar, so he was pushing the doors on the hinged side. No wonder nothing happened. Attractive doors. Stylish. Probably won a design prize.

Two of the most important characteristics of good design are dis- coverability and understanding. Discoverability: Is it possible to even figure out what actions are possible and where and how to per- form them? Understanding: What does it all mean? How is the product supposed to be used? What do all the different controls and settings mean?

The doors in the story illustrate what happens when discoverabil- ity fails. Whether the device is a door or a stove, a mobile phone or a nuclear power plant, the relevant components must be visible, and they must communicate the correct message: What actions are possible? Where and how should they be done? With doors that push, the designer must provide signals that naturally indi- cate where to push. These need not destroy the aesthetics. Put a vertical plate on the side to be pushed. Or make the supporting pillars visible. The vertical plate and supporting pillars are natural signals, naturally interpreted, making it easy to know just what to do: no labels needed.

With complex devices, discoverability and understanding re- quire the aid of manuals or personal instruction. We accept this if the device is indeed complex, but it should be unnecessary for simple things. Many products defy understanding simply because they have too many functions and controls. I don't think that sim- ple home appliances-stoves, washing machines, audio and tele- vision sets-should look like Hollywood's idea of a spaceship control room. They already do, much to our consternation. Faced with a bewildering array of controls and displays, we simply mem- orize one or two fixed settings to approximate what is desired.

In England I visited a home with a fancy new Italian washer- dryer combination, with super-duper multisymbol controls, all to do everything anyone could imagine doing with the washing and drying of clothes. The husband (an engineering psychologist) said he refused to go near it. The wife (a physician) said she had simply memorized one setting and tried to ignore the rest. I asked to see the manual: it was just as confusing as the device. The whole pur- pose of the design is lost.

The Complexity of Modern Devices

All artificial things are designed. Whether it is the layout of fur- niture in a room, the paths through a garden or forest, or the in- tricacies of an electronic device, some person or group of people had to decide upon the layout, operation, and mechanisms. Not all designed things involve physical structures. Services, lectures, rules and procedures, and the organizational structures of busi- nesses and governments do not have physical mechanisms, but their rules of operation have to be designed, sometimes informally, sometimes precisely recorded and specified.

But even though people have designed things since prehistoric times, the field of design is relatively new, divided into many areas of specialty. Because everything is designed, the number of areas is enormous, ranging from clothes and furniture to complex control rooms and bridges. This book covers everyday things, focusing on the interplay between technology and people to ensure that the products actually fulfill human needs while being understand- able and usable. In the best of cases, the products should also be delightful and enjoyable, which means that not only must the re- quirements of engineering, manufacturing, and ergonomics be sat- isfied, but attention must be paid to the entire experience, which means the aesthetics of form and the quality of interaction. The major areas of design relevant to this book are industrial design, interaction design, and experience design. None of the fields is well defined, but the focus of the efforts does vary, with industrial designers emphasizing form and material, interactive designers emphasizing understandability and usability, and experience de- signers emphasizing the emotional impact. Thus:

Industrial design: The professional service of creating and developing concepts and specifications that optimize the function, value, and appearance of products and systems for the mutual benefit of both user and manufacturer (from the Industrial Design Society of America's website).

Interaction design: The focus is upon how people interact with tech- nology. The goal is to enhance people's understanding of what can be done, what is happening, and what has just occurred. Interaction de- sign draws upon principles of psychology, design, art, and emotion to ensure a positive, enjoyable experience.

Experience design: The practice of designing products, processes, ser- vices, events, and environments with a focus placed on the quality and enjoyment of the total experience.

Design is concerned with how things work, how they are con- trolled, and the nature of the interaction between people and technology. When done well, the results are brilliant, pleasurable products. When done badly, the products are unusable, leading to great frustration and irritation. Or they might be usable, but force us to behave the way the product wishes rather than as we wish.

Machines, after all, are conceived, designed, and constructed by people. By human standards, machines are pretty limited. They do not maintain the same kind of rich history of experiences that people have in common with one another, experiences that enable us to interact with others because of this shared understanding. Instead, machines usually follow rather simple, rigid rules of be- havior. If we get the rules wrong even slightly, the machine does what it is told, no matter how insensible and illogical. People are imaginative and creative, filled with common sense; that is, a lot of valuable knowledge built up over years of experience. But instead of capitalizing on these strengths, machines require us to be precise and accurate, things we are not very good at. Machines have no leeway or common sense. Moreover, many of the rules followed by a machine are known only by the machine and its designers.

When people fail to follow these bizarre, secret rules, and the machine does the wrong thing, its operators are blamed for not understanding the machine, for not following its rigid specifica- tions. With everyday objects, the result is frustration. With complex devices and commercial and industrial processes, the resulting difficulties can lead to accidents, injuries, and even deaths. It is time to reverse the situation: to cast the blame upon the machines and their design. It is the machine and its design that are at fault. It is the duty of machines and those who design them to understand people. It is not our duty to understand the arbitrary, meaningless dictates of machines.

The reasons for the deficiencies in human-machine interaction are numerous. Some come from the limitations of today's technol- ogy. Some come from self-imposed restrictions by the designers, often to hold down cost. But most of the problems come from a complete lack of understanding of the design principles necessary for effective human-machine interaction. Why this deficiency? Be- cause much of the design is done by engineers who are experts in technology but limited in their understanding of people. "We are people ourselves," they think, "so we understand people." But in fact, we humans are amazingly complex. Those who have not studied human behavior often think it is pretty simple. Engineers, moreover, make the mistake of thinking that logical explanation is sufficient: "If only people would read the instructions," they say, "everything would be all right."

Engineers are trained to think logically. As a result, they come to believe that all people must think this way, and they design their machines accordingly. When people have trouble, the engineers are upset, but often for the wrong reason. "What are these people doing?" they will wonder. "Why are they doing that?" The prob- lem with the designs of most engineers is that they are too logical. We have to accept human behavior the way it is, not the way we would wish it to be.

I used to be an engineer, focused upon technical requirements, quite ignorant of people. Even after I switched into psychology and cognitive science, I still maintained my engineering emphasis upon logic and mechanism. It took a long time for me to realize that my understanding of human behavior was relevant to my in- terest in the design of technology. As I watched people struggle with technology, it became clear that the difficulties were caused by the technology, not the people.

I was called upon to help analyze the American nuclear power plant accident at Three Mile Island (the island name comes from the fact that it is located on a river, three miles south of Middle- town in the state of Pennsylvania). In this incident, a rather simple mechanical failure was misdiagnosed. This led to several days of difficulties and confusion, total destruction of the reactor, and a very close call to a severe radiation release, all of which brought the American nuclear power industry to a complete halt. The op- erators were blamed for these failures: "human error" was the im- mediate analysis. But the committee I was on discovered that the plant's control rooms were so poorly designed that error was inevi- table: design was at fault, not the operators. The moral was simple: we were designing things for people, so we needed to understand both technology and people. But that's a difficult step for many engineers: machines are so logical, so orderly. If we didn't have people, everything would work so much better. Yup, that's how I used to think.

My work with that committee changed my view of design. To- day, I realize that design presents a fascinating interplay of tech- nology and psychology, that the designers must understand both. Engineers still tend to believe in logic. They often explain to me in great, logical detail, why their designs are good, powerful, and wonderful. "Why are people having problems?" they wonder. "You are being too logical," I say. "You are designing for people the way you would like them to be, not for the way they really are."

When the engineers object, I ask whether they have ever made an error, perhaps turning on or off the wrong light, or the wrong stove burner. "Oh yes," they say, "but those were errors." That's the point: even experts make errors. So we must design our ma- chines on the assumption that people will make errors. (Chapter 5 provides a detailed analysis of human error.)