The author : Donald A. Norman
Donald A. Norman is an Apple Fellow at Apple Computer and Professor Emeritus at the University of California, San Diego where he was founding chair of the department of Cognitive Science. He was one of the founders of the Cognitive Science Society and has been chair of the society and editor of its journal, Cognitive Science. He is a fellow of the American Academy of Arts and Sciences. Norman serves on advisory boards for the school of computer science at the Georgia Institute of Technology, the, Institute for the Learning Sciences, Northwestern University; the Nijmegen Institute for Cognition Research and Information Technology, University of Nijmegen (the Netherlands); and the Association for Software Design. At Apple Computer, Norman works to guide the User experience side of product development and to move the computer industry beyond the current generation of systems to new models of interaction.
This book is intended to make you aware of the problem of design and improving things. Donald A. Norman gives wonderful examples, makes readers more sensitive to the problems of life and to the needs of people. The examples in this book come from Europe and the United States, but the same problems exist all over the world. The title of this book is a case history of design. A writer is also a designer, a designer of the words rather than of things such as The Psychology of Everyday Things (POET emphasizes the understanding of everyday things, things with knobs and dials, control and switch, lights and meters), Design for Usability: The Psychology of Everyday Tools, and The Design of Everyday Things. This book has seven chapters that are one: The Psychopathology of Everyday Things, two: The Psychology of Everyday Actions, three: Knowledge in the Head and in the World, four: Knowing What to Do, five: To Err Is Human, six: The Design Challenge, and seven: Use-Centered Design.
Why do we put up with the frustrations of everyday objects, with objects that we can't figure out how to use, with those neat plastic-wrapped packages that seem impossible to open, with doors that trap people, with washing machines and dryers that have become too confusing to use. Well-designed objects are easy to interpret and understand. They contain visible clues to their operation. Poorly designed objects can be difficult and frustrating to use. They provide no clues or sometimes false clues. They trap the user and thwart the normal process of interpretation and understanding. The result is a world filled with frustration, with objects that cannot be understood, with devices that lead to error. If the design was so bad, if the controls so unusable, why did the couple purchase it? If people keep buying poorly designed products, manufacturers and designers will think they are doing the right thing and continue as usual. This book is an attempt to change things.
The example of poorly designed is "Doors". There are not much you can do to a door: you can open it or shut it. The problem is " Do you have trouble opening doors?" Should you pull or push, on the left or the right? Maybe the door slides. The answer how to open the door should be given by the design, without any need for words or symbols, certainly without any need for trial and error. The designer aims for utility, not beauty. The door story illustrates one of the most important principles of design: visibility. With door that push, the designer must provide signals that naturally indicate where to push. Put a vertical plate on the side to be pushed, nothing on the other. The vertical plate is natural signals, naturally interpreted, without any need to be conscious of them.
Provide a good conceptual model and make things visible are the principles of design for understandability and usability. A good conceptual model allows us it predict the effects of actions. As long as things work properly we can manage. When things go wrong, however, or when we come upon a novel situation, then we need a deeper understanding, a good model. Mapping is a technical term meaning the relationship between two things, in this case between the controls and movements and the results in the world. Consider the mapping relationship s involved in steering a car. To turn the car to the right, one turns the steering wheel clockwise (so that its top moves to the right). The mapping is easily learned and always remembered. The excellent example of natural mapping is Seat Adjustment Control from a Mercedes-Benz. The control is in the shape of the seat itself: the mapping is straightforward. When things are visible, they tend to be easier than when they are not. In addition, there must be a close, natural relationship between the control and its function: a natural mapping. Feedback–sending back to the user information about what action has actually been done, what result has been accomplished–is a well-known concept in the science of control and information theory. The principles are simple but rarely incorporated into design. Good design takes care planning, thought. It takes conscious attention to the needs of the user.
The designer must assume that all possible errors will occur and design so as to minimize the chance of the error in the first place, or its effects once it gets made. Errors should be easy to detect, they should have minimal consequences, and, if possible, their effects should be reversible. Designing well is not easy. It usually takes five or six attempts to get a product right. This may be acceptable in an established product, but consider what it means in a new one. The author gives a simple example of good design that is the 31/2 inch magnetic diskette for computer, a small circle of "floppy" magnetic material encased in hard plastic. A sliding metal cover protects the delicate magnetic surface when the diskette is not in use and automatically opens when the diskette is inserted into the computer.
The good idea that Norman gives to the readers is to know theories about thermostat. "If you think that the room or oven will heat (or cool) faster if the, thermostat is turned all the way to the maximum setting, you are wrong. The correct story is that the thermostat is just an on-off switch. It treats the heater, oven, and air conditioner as all-or-nothing devices that can be either fully on or fully off, with no in-between states. The thermostat turns the heater, oven, or air conditioner completely on, at full power, until the temperature setting on the thermostat is reached. Then it turns the unit completely off."
Knowledge in the head and in the world, precise behavior can emerge from imprecise knowledge for four reasons that are Information is in the world, Great precision is not required, Natural constraints are present, Cultural constraints are present. Because of these natural and artificial constraints, the number of alternatives for any particular situation is reduced, as are the amount and specificity of knowledge required within human memory. People function through their use of two kinds of knowledge: knowledge of and knowledge how. Knowledge of, what psychologists call declarative knowledge, include the knowledge of facts and rules. "Stop at red right." "To get the key out of the ignition, the car must be in reverse." Declarative knowledge is easy to write down and to teach. Knowledge how, what psychologists call procedural knowledge, is the knowledge that enables a person to perform music, to stop a car smoothly with a flat tire on an icy road. Procedural knowledge is difficult or impossible to write down and difficult to teach. It is best taught by demonstration and best learned through practice. Procedural knowledge is largely subconscious.
As we have seen, knowledge in the world, external knowledge, can be very valuable. But it, too, has drawbacks. For one, it is available only if you are there, in the appropriate situation. When you are somewhere else, or if the world has change meanwhile, the knowledge is gone. A folk saying captures this situation well: "Out of sight, out of mind." One of the most important and interesting aspects of the role of external memory is reminding. There are two different aspects to a reminder: the signal and the message. Just as in doing an action we can distinguish between knowing what can be done and knowing hoe to do it, in reminding we must distinguish between knowing that something is to be remember and remembering what it is. Knowledge in the world acts as its own reminder. It can help us recover structures that we otherwise would forget. Knowledge in the world is easier to learn, but often more difficult to use.
There are lots of ways for a designer to deal with errors. The critical thing, however, is to approach the topic with the proper philosophy. The designer should not think of a simple dichotomy between errors and corrected behavior; rather, the entire interaction should be treated as a cooperative endeavor between person and machine, one in which misconceptions can arise on either side. This philosophy is much easier to implement on something like a computer that has the ability to make decisions on its own than one thing like door and power plants, which do not have such intelligence. Design should:
The Design of Everyday things by Donald A. Norman has 257 pages. The price of this book is US $ 15.95, and published in 1990 by Doubleday in New York, New York.