That is the title of a great book by Donald Norman - 'The Design of Everyday Things'. I only wish that I would have read this book years ago.
The book introduces four major design principles:
Conceptual Models - good design is a an act of communication between the designer and the user, except that the ALL the communication has to come about by the appearance of the device itself. The location and operation of the controls require a conceptual model - an obvious and natural relationship between their location and the operation they control so you always know which control does what. When designers fail to provide a conceptual model, we will be forced to make up our own, and the ones we make up are apt to be wrong.
Feedback - in design, it is important to show the effect of an action. Without feedback, one is always wondering whether anything has happened. Maybe the button wasn't pushed hard enough; maybe the machine has stopped working; maybe it is doing the wrong thing; Without feedback, we turn equipment off at improper times or restart unnecessarily, losing all of our recent work. Or we repeat the command and end up having the operation done twice, often to our detriment. Feedback is critical.
Constraints - The surest way to make something easy to use, with few errors, is to make it impossible to do otherwise - to constrain the choices. Failure to design with constraints is one reason for all those warnings and attempts to give instructions. One of the cool examples from the book is where he talked about threading a reel of film through a projector, contrasted by inserting a tape into a VCR...
Affordances - a good designer makes sure that appropriate actions are perceptible and inapropriate ones invisible.
There was a good story early in the book about a phone - I can't seem to find a good picture online...
I recently spent six months at the Applied Psychology Unit in Cambridge, England. Just before I arrived the British Telecom Company had installed a new telephone system. It had lots and lots of features.
The telephone instrument itself was unremarkable. It was the standard twelve-button, push-button phone, except that it had an extra key labeled "R" off on the side. (I never did find out what that key did.)
The telephone system was a standing joke. Nobody could use all the features. One person even started a small research project to record people's confusions. Another person wrote a small "expert systems" computer program, one of the new toys of the field of artificial intelligence; the program can reason through complex situations. If you wanted to use the phone system, perhaps to make a conference call among three people, you asked the expert system and it would explain how to do it. So, you're on the line with someone and you need to add a third person to the call. First turn on your computer. Then load the expert system. After three or four minutes (needed for loading the program), type in what you want to accomplish. Eventually the computer will tell you what to do--if you can remember why you want to do it, and if the person on the other end of the line is still around. But, as it happens, using the expert system is a lot easier than reading and understanding the manual provided with the telephone.
Why is that telephone system so hard to understand? Nothing in it is conceptually difficult. Each of the operations is actually quite simple. A few digits to dial, that's all. The telephone doesn't even look complicated. There are only fifteen controls: the usual twelve buttons--ten labeled 0 through 9, #, an *--plus the handset itself, the handset button, and the mysterious "R" button. All except the "r" are the everyday parts of a normal modern telephone. Why was the system so difficult?
A designer who works for a telephone company told me the following story:
"I was involved in designing the faceplate of some of those new multifunction phones, some of which have buttons labeled "R." The "R" button is kind of a vestigial feature. It is very hard to remove features of a newly designed product that had existed in an earlier version. It's kind of like physical evolution. If a feature is in the genome, and if that feature is not associated with any negativity (i.e., no customers gripe about it), then the feature hangs on for generations.
"It is interesting that things like the "R" button are largely determined through examples. Somebody asks, 'What is the "R" button used for?' and the answer is to give an example: 'You can push "R" to access loudspeaker paging.' If nobody can think of an example, the feature is dropped. Designers are pretty bright people, however. They can come up up with a plausible-sounding example for almost anything. Hence, you get features, many many features, and these features hang on for a long time. The end result is complex interfaces for essentially simple things."
As I pondered this problem, I decided it would make sense to compare the phone system with something that was of equal or greater complexity but easier to use. So let us temporarily leave the difficult telephone system and take a look at my automobile. I bought a car in Europe. When I picked up the new car at the factory, a man from the company sat in the car with me and went over each control, explaining its function. When he had gone through the controls once, I said fine, thanked him, and drove away. That was all the instruction it took. There are 112 controls inside the car. This isn't quite as bad as it sounds. Twenty-five of them are on the radio. Another 7 are the temperature control system, and 11 work the windows and sunroof. The trip computer has 14 buttons, each matched with a specific function. So four devices--the radio, temperature controls, windows, and trip computer--have together 57 controls, or just over 50 percent of the ones available.
Why is the automobile, with all its varied functions and numerous controls, so much easier to learn and to use than the telephone system, with its much smaller set of functions and controls? What is good about the design of the car? Things are visible. There are good mappings, natural relationships, between the controls and the things controlled. Single controls often have single functions. There is good feedback. The system is understandable. In general, the relationships among the user's intentions, the required actions, and the results are sensible, nonarbitrary, and meaningful.
What is bad about the design of the telephone? There is no visible structure. Mappings are arbitrary: there is no rhyme or reason to the relationship between the actions the user must perform and the results to be accomplished. The controls have multiple functions. There isn't good feedback, so the user is never sure whether the desired result has been obtained. The system, in general, is not understandable; its capabilities aren't apparant. In general, the relationships among the user's intentions, the required actions, and the results are completely arbitrary.
I think just about anyone would enjoy the book - whether you design things or not.
One thing I've learned is that good design is invisible. We tend not to think about it. Poor design, on the other hand, is obvious and painful... and can be life-threatening, as Mr. Norman points out in the book (he actually consulted on the accident at the Three Mile Island nuclear power plant).
So, what are some everyday items that you think are poorly designed? What would you do to improve them?