In the first edition of this book, then called POET, The Psychology of Everyday Things, I started with these lines: "This is the book I always wanted to write, except I didn't know it." Today I do know it, so I simply say, "This is the book I always wanted to write."
This is a starter kit for good design. It is intended to be enjoyable and informative for everyone: everyday people, technical people, designers, and non-designers. One goal is to turn everyone into great observers of the absurd, of the poor design that gives rise to so many of the problems of modern life, especially of modern technology. It will also turn everyone into observers of the good, of the places where thoughtful designers have worked to make our lives easier and smoother. Good design is actually a lot harder to notice than poor design, in part because good designs fit our needs so well that the design is invisible, serving us without drawing attention to itself. Bad design, on the other hand, screams out its inadequacies, making itself very noticeable.
Along the way I lay out the fundamental principles required to eliminate problems, to turn our everyday stuff into enjoyable products that provide pleasure and satisfaction. The combination of good observation skills along with good design principles is a powerful tool, one that everyone can use, even people who are not professional designers. Why? Because everyone is a designer in the sense that all of us deliberately design our lives, our rooms, and the way we do things. We can also design workarounds, ways of overcoming the flaws of existing devices. So one purpose of this book is to give you back control over the products in your life: to know how to select useable and understandable ones, to know how to fix those that aren't so usable or understandable.
The first edition of the book has lived a long and healthy life. It has been read by ordinary people and by designers. It has been assigned in courses and handed out as required readings in many companies. Now, more than twenty years after its release, the book is still popular. I am delighted by the response and by the number of people who correspond with me about it, who send me further examples of thoughtless, inane design plus occasional examples of superb design. Many readers have told me that it has changed their lives, making them more sensitive to the problems of life and to the needs of people. Some changed their careers and became designers because of the book. The response has been amazing.
Why a Revised Edition?
In the 25 years that have passed since the first edition of the book, technology has undergone massive change. Neither cellphones nor the internet were in widespread usage when I wrote the book. Home networks were unheard of. Moore's law proclaims that the power of computer processors doubles roughly every two years. This means that today's computers are 5,000 times more powerful than the ones available when the book was first written.
Although the fundamental design principles of DOET are still as true and as important as when the book was first written, the examples were badly out of date. "What is a slide projector?" students ask. Even if nothing else were to be changed, the examples had to be updated.
The principles of effective design also had to be brought up to date. Human-Centered Design, HCD, has emerged since the first edition, partially inspired by the book. This edition has an entire chapter devoted to the HCD process of product development. The first edition of the book focused upon making products understandable and usable. The total experience of a product covers much more than its usability: aesthetics, pleasure, and fun play critically important roles. There was no discussion about pleasure, enjoyment, or emotion. Emotion is so important that I wrote an entire book, Emotional Design, about the role it plays in design. These issues are also now included in this edition.
My experiences in industry have taught me about the complexities of the real world, how cost and schedules are critical, the need to pay attention to competition, and the importance of multidisciplinary teams. I learned that the successful product has to appeal to customers, and the criteria they use to determine what to purchase may have surprisingly little overlap with the aspects that are important during usage. The best products do not always succeed. Brilliant new technologies might take decades to become accepted. To understand products, it is not enough to understand design or technology: it is critical to understand business.
What Has Changed?
For readers familiar with the earlier edition of this book, here is a brief review of the changes.
What has changed? Not much. Everything.
When I started, I assumed that the basic principles were still true, so all I needed to do was update the examples. But in the end, I rewrote everything. Why? Because although all the principles still applied, in the 25 years since the first edition, much has been learned. I also now know which parts were difficult and therefore need better explanations. In the interim, I also wrote many articles and six books on related topics, some of which I thought important to include in the revision. For example, the original book says nothing of emotion or the importance of appearance, pleasure, and what has been come to be called "user experience" (a term that I was among the first to use, when in the early 1990s, the group I headed at Apple called itself "the User Experience Architect's office"). This needed to be here.
Finally, my exposure to industry taught me much about the way products actually get deployed, so I added considerable information about the impact of budgets, schedules, and competitive pressures. When I wrote the original book I was an academic researcher. Today, I have been an industry executive (Apple, HP, and some startups), a consultant to numerous companies, and a board member of companies. I had to include my learnings from these experiences.
Finally, one important component of the original edition was its brevity. The book could be read quickly as a basic, general introduction. I kept that feature unchanged. I tried to delete as much as I added to keep the total size about the same. The book is meant to be an introduction: advanced discussions of the topics, as well as a large number of important, but more advanced, topics have been left out to maintain the compactness. The previous edition lasted 25 years: 1988-2013. If the new edition is to last as long, 2013-2038, I had to be careful to choose examples that would not be dated 25 years from now. As a result, I have tried not to give specific company examples. After all, who remembers the companies of 25 years ago? Who can predict what new companies will arise, what existing companies will disappear, and what new technologies will arise in the next 25 years? The one thing I can predict with certainty is that the principles of human psychology will remain the same, which means that the design principles here, based on psychology, on the nature of human cognition, emotion, action, and interaction with the world will remain unchanged.
Here is a brief summary of the changes, chapter by chapter.
Chapter 1: Psychopathology Of Everyday Things
Signifiers are the most important addition to the chapter, a concept first introduced in my book Living with Complexity. The first edition had a focus upon affordances, but although affordances make sense for interaction with physical objects, they are confusing when dealing with virtual ones. As a result, affordances have created much confusion in the world of design. Affordances define what actions are possible. Signifiers specify how people discover those possibilities: signifiers are signs, perceptible signals of what can be done. Signifiers are of far more importance to designers than are affordances. Hence, the extended treatment.
I added a very brief section on Human-Centered Design (HCD), a term that didn't yet exist when the first edition was published, although looking back, we see that the entire book was about HCD.
Other than that, the chapter is the same, and although all the photographs and drawings are new, the examples are pretty much the same.
Chapter 2: The Psychology Of Everyday Actions
The chapter has one major addition to the coverage in the first edition: The addition of emotion. The seven-stage model of action has proven to be influential, as has the three level model of processing (introduced in my book Emotional Design). In this chapter I show the interplay between these two, that different emotions arise at the different stages, and showing which stages are primarily located at each of the three levels of processing (Visceral for the elementary levels of motor action performance and perception), Behavioral for the levels of action specification and initial interpretation of the outcome, and Reflective for the development of goals, plans, and the final stage of evaluation of the outcome).
Chapter 3: Knowledge in the Head and in the World
Aside from improved and updated examples, the most important addition to this chapter is a section on culture, which is of special importance to my discussion of "natural mappings." What seems natural in one culture may not be in another. The section examines the way different cultures view time - the discussion might surprise you.
Chapter 4: Knowing What To Do: Constraints, Discoverability, and Feedback
Few substantive changes. Better examples. The elaboration of forcing functions into two kinds: lock-in and lock-out. And a section on destination control elevators, illustrating how change can be extremely disconcerting, even to professionals, even if the change is for the better.
Chapter 5: Human Error? No, Bad Design
The basics are unchanged, but the chapter itself has been heavily revised. I update the classification of errors to fit advances since the publication of the first edition. In particular, I now divide slips into two main categories - action based and memory lapses - and mistakes into three categories - rule based, knowledge based, and memory lapses. (These distinctions are now common, but I introduce a slightly different way to treat memory lapses.)
Although the multiple classifications of slips provided in the first edition are still valid, many have little or no implications for design, so they have been eliminated from the revision. I provide more design-relevant examples. I show the relationship of the classification of errors, slips and mistakes to the seven stage model of action, something absent new in this revision.
The chapter concludes with a quick discussion of the difficulties posed by automation (from my book "Design of Future Things") and what I consider the best new approach to deal with design so as to either eliminate or minimize the human error: resilience engineering.
Chapter 6: Design Thinking
This chapter is completely new. I discuss two views of human-centered design: the British Design Council's double-diamond model. The first diamond is the divergence followed by convergence of possibilities to determine the appropriate problem. The second diamond is a divergence-convergence to determine an appropriate solution. I describe the traditional HCD iteration of observation, ideation, prototyping, and testing. Then I introduce activity-centered design as a more appropriate variant of human-centered design in many circumstances. These sections cover the theory.
The chapter then takes a radical shift in position, starting with a section entitled "What I just told you? It doesn't really work that way." Here is where I introduce Norman's law: The day the product team is announced, it is behind schedule and over its budget.
I discuss challenges of design within a company, where schedules, budgets, and the competing requirements of the different divisions all provide severe constraints upon what can be accomplished. Readers from industry have told me that they welcome these sections for they do capture the real pressures upon them.
The chapter concludes with a discussion of the role of standards (modified from a similar discussion in the earlier edition), plus some more general design guidelines.
Chapter 7: Design in the World of Business
This chapter is also completely new, continuing the theme started in Chapter 6 of design in the real world. Here I discuss featuritis, the changes being forced upon us through the invention of new technologies, and the distinction between incremental and radical innovation. Everyone wants radical innovation, but the truth is, most radical innovations fail, and even when they do succeed, it can take multiple decades before they are accepted. Radical innovation, therefore, is relatively rare: incremental innovation is common.
The techniques of human-centered design are appropriate to incremental innovation: they cannot lead to radical innovations.
The chapter concludes with discussions of the trends to come, the future of books, the moral obligations of design, and the rise of small, do-it yourself, makers who are starting to revolutionize the way ideas are conceived of and introduced into the marketplace: "the rise of the small," I call it.
With the passage of time, the psychology of people stays the same, but the tools and objects in the world change. Cultures change. Technologies change. The principles of design still hold, but the way they get applied needs to be modified to account for new activities, new technologies, new methods of communication and interaction. The first edition of DOET was appropriate for the 20th century: this edition is for the 21st century.