by Don Norman
THE
DESIGN
OF EVERYDAY
THINGS
ALSO BY
DON NORMAN
TEXTBOOKS
Memory and Attention: An Introduction to
Human Information Processing.
First edition, 1969; second edition 1976
Human Information Processing.
(with Peter Lindsay: first edition, 1972; second edition 1977)
SCIENTIFIC MONOGRAPHS
Models of Human Memory
(edited, 1970)
Explorations in Cognition
(with David E. Rumelhart and the LNR Research Group, 1975)
Perspectives on Cognitive Science
(edited, 1981)
User Centered System Design: New Perspectives on Human-Computer Interaction
(edited with Steve Draper, 1986)
TRADE BOOKS
Learning and Memory, 1982
The Psychology of Everyday Things, 1988
The Design of Everyday Things
1990 and 2002 (paperbacks of The Psychology of Everyday Things with new prefaces)
The Design of Everyday Things
Revised and Expanded Edition, 2013
Turn Signals Are the Facial Expressions of Automobiles, 1992
Things That Make Us Smart, 1993
The Invisible Computer: Why Good Products Can Fail, the Personal Computer Is So Complex, and Information Appliances Are the Answer, 1998
Emotional Design: Why We Love (or Hate) Everyday Things, 2004
The Design of Future Things, 2007
A Comprehensive Strategy for Better Reading: Cognition and Emotion, 2010
(with Masanori Okimoto; my essays, with commentary in Japanese, used for teaching English as a second language to Japanese speakers)
Living with Complexity, 2011
CD-ROM
First person: Donald A. Norman. Defending Human Attributes in the Age of the Machine, 1994
THE
DESIGN
OF EVERYDAY
THINGS
REVISED AND EXPANDED EDITION
Don Norman
BASIC BOOKS
A Member of the Perseus Books Group
New York
Copyright © 2013 by Don Norman
Published by Basic Books,
A Member of the Perseus Books Group
All rights reserved. No part of this book may be reproduced in any manner whatsoever without written permission except in the case of brief quotations embodied in critical articles and reviews. For information, address Basic Books, 250 West 57th Street, 15th Floor, New York, New York 10107.
Books published by Basic Books are available at special discounts for bulk purchases in the United States by corporations, institutions, and other organizations. For more information, please contact the Special Markets Department at the Perseus Books Group, 2300 Chestnut Street, Suite 200, Philadelphia, PA 19103, or call (800) 810-4145, ext. 5000, or e-mail [email protected].
Library of Congress Cataloging-in-Publication Data
Norman, Donald A.
[Psychology of everyday things]
The design of everyday things / Don Norman.—Revised and expanded edition.
pages cm
ISBN 978-0-465-07299-6 (ebook) 1. Industrial design—Psychological aspects. 2. Human engineering. I. Title.
TS171.4.N672013
745.2001'9—dc23
2013024417
10987654321
For Julie
CONTENTS
Preface to the Revised Edition
1The Psychopathology of Everyday Things
The Complexity of Modern Devices
Human-Centered Design
Fundamental Principles of Interaction
The System Image
The Paradox of Technology
The Design Challenge
2The Psychology of Everyday Actions
How People Do Things: The Gulfs of Execution and Evaluation
The Seven Stages of Action
Human Thought: Mostly Subconscious
Human Cognition and Emotion
The Seven Stages of Action and the Three Levels of Processing
People as Storytellers
Blaming the Wrong Things
Falsely Blaming Yourself
The Seven Stages of Action: Seven Fundamental Design Principles
3Knowledge in the Head and in the World
Precise Behavior from Imprecise Knowledge
Memory Is Knowledge in the Head
The Structure of Memory
Approximate Models: Memory in the Real World
Knowledge in the Head
The Tradeoff Between Knowledge in the World and in the Head
Memory in Multiple Heads, Multiple Devices
Natural Mapping
Culture and Design: Natural Mappings Can Vary with Culture
4Knowing What to Do: Constraints Discoverability, and Feedback
Four Kinds of Constraints: Physical, Cultural, Semantic, and Logical
Applying Affordances, Signifiers, and Constraints to Everyday Objects
Constraints That Force the Desired Behavior
Conventions, Constraints, and Affordances
The Faucet: A Case History of Design
Using Sound as Signifiers
5Human Error? No, Bad Design
Understanding Why There Is Error
Deliberate Violations
Two Types of Errors: Slips and Mistakes
The Classification of Slips
The Classification of Mistakes
Social and Institutional Pressures
Reporting Error
Detecting Error
Designing for Error
When Good Design Isn’t Enough
Resilience Engineering
The Paradox of Automation
Design Principles for Dealing with Error
6Design Thinking
Solving the Correct Problem
The Double-Diamond Model of Design
The Human-Centered Design Process
What I Just Told You? It Doesn’t Really Work That Way
The Design Challenge
Complexity Is Good; It Is Confusion That Is Bad
Standardization and Technology
Deliberately Making Things Difficult
Design: Developing Technology for People
7Design in the World of Business
Competitive Forces
New Technologies Force Change
How Long Does It Take to Introduce a New Product?
Two Forms of Innovation: Incremental and Radical
The Design of Everyday Things: 1988–2038
The Future of Books
The Moral Obligations of Design
Design Thinking and Thinking About Design
Acknowledgments
General Readings and Notes
References
Index
PREFACE TO THE REVISED EDITION
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 nondesigners. One goal is to turn readers 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 them into observers of the good, of the ways in which thoughtful designers have worked to make our lives easier and smoother. Good design is actually a lo
t 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 and good design principles is a powerful tool, one that everyone can use, even people who are not professional designers. Why? Because we are all designers 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 back your control over the products in your life: to know how to select usable 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. Its name was quickly changed to Design of Everyday Things (DOET) to make the title less cute and more descriptive. DOET has been read by the general public 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 twenty-five years that have passed since the first edition of the book, technology has undergone massive change. Neither cell phones 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 five thousand times more powerful than the ones available when the book was first written.
Although the fundamental design principles of The Design of Everyday Things are still as true and as important as when the first edition was written, the examples were badly out of date. “What is a slide projector?” students ask. Even if nothing else was 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 that book. This current 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 of 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 twenty-five 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 what has 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 (I failed). 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 from 1988 to 2013. If the new edition is to last as long, 2013 to 2038, I had to be careful to choose examples that would not be dated twenty-five years from now. As a result, I have tried not to give specific company examples. After all, who remembers the companies of twenty-five years ago? Who can predict what new companies will arise, what existing companies will disappear, and what new technologies will arise in the next twenty-five 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: The 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 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, show that different emotions arise at the different stages, and show 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 lockout. 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 new in this revision.
The chapter concludes with a quick discussion of the difficulties posed by automation (from my book The Design of Future Things) and what I consider the best new approach to deal with design so as to either eliminate or minimize 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 and the traditional HCD iteration of observation, ideation, prototyping, and testing. 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 introduce activity-centered design as a more appropriate variant of human-centered design in many circumstances. These sections cover the theory.