The Design of Everyday Things - Don NORMAN - ISBN: 978-0-465-05065-9
- Chapter 1: The Psychopathology of Everyday Things
- Chapter 2: The Psychology of Everyday Actions
- Chapter 3: Knowledge in the Head and in the World
- Chapter 4: Knowing What To Do: Constraints, Discoverability, and Feedback
- Chapter 5: Human Error? No, Bad Design
- Chapter 6: Design Thinking
- Chapter 7: Design in the World of Business
My problems with doors have become so well known that confusing doors are often called "Norman doors".
Two of the most important characteristics of good design are discoverability and understanding.
Discoverability: Is it possible to even figure out what actions are possible and where and how to perform them?
Understanding: What does it all mean? How is the product supposed to be used? What do all the different controls and settings mean?
With complex devices, discoverability and understanding require the aid of manuals or personal instruction. We accept this if the device is indeed complex, but it should be unnecessary for simple things.
All artificial things are designed.
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 specifications. 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.
Why this deficiency? Because much of the design is done by engineers who are experts in technology but limited in their understanding of people.
The problem 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.
The solution is human-centered design (HCD), an approach that puts human needs, capabilities, and behavior first, then designs to accommodate those needs, capabilities, and ways of behaving. Good design requires good communication, especially from machine to person, indicating what actions are possible, what is happening, and what is about to happen. Communication is especially important when things go wrong.
Affordances determine what actions are possible. Signifiers communicate where the action should take place. We need both.
Affordances are the possible interactions between people and the environment. Some affordances are perceivable, others are not.
Perceived affordances often act as signifiers, but they can be ambiguous.
Signifiers signal things, in particular what actions are possible and how they should be done.
Signifiers must be perceivable, else they fail to function.
Consider a bookmark, a deliberately placed signifier of one’s place in reading a book. But the physical nature of books also makes a bookmark an accidental signifier, for its placement also indicates how much of the book remains. Most readers have learned to use this accidental signifier to aid in their enjoyment of the reading. With few pages left, we know the end is near. And if the reading is torturous, as in a school assignment, one can always console oneself by knowing there are “only a few more pages to get through.” Electronic book readers do not have the physical structure of paper books, so unless the software design deliberately provides a clue, they do not convey any signal about the amount of text remaining.
The relationship between a control and its results is easiest to learn wherever there is an understandable mapping between the controls, the actions, and the intended result.
Related controls should be grouped together. Controls should be close to the item being controlled.
What is natural for one culture is snoot necessarily naturel for another.
Every drive to a traffic intersection and wait an inordinate amount of time? What is missing in all these cases is feedback: some way of letting you know that the system is working of your request.
Feedback must be immediate: even a delay of a tenth of a second can be disconcerting.
Poor feedback can be worse than no feedback at all, because it is distracting, uninformative and in many cases irritating and anxiety-provoking.
A conceptual model is an explanation, usually highly simplified, of how something works. It doesn’t have to be complete or even accurate as long as it is useful. The files, folders, and icons you see displayed on a computer screen help people create the conceptual model of documents and folders inside the computer, or of apps or applications residing on the screen, waiting to be summoned. In fact, there are no folders inside the computer- those are effective conceptualizations designed to make them easier to use.
Good conceptual models are the key to understandable, enjoyable products: good communication is the key to good conceptual models.
The same technology that simplifies life by providing more functions in each device also complicates life by making the device harder to learn, harder to use.
Seven stages of action: one for goals, three for execution, and three for evaluation
-1 Goal (form the goal)
-2 Plan (the action)
-3 Specify (an action sequence)
-4 Perform (the action sequence)
-5 Perceive (the state of the world)
-6 Interpret (the perception)
-7 Compare (the outcome with the goal)
This is called a root cause analysis: asking “Why?” until the ultimate, fundamental cause of the activity is reached.
Once you realize that they don’t really want the drill, you realize that perhaps they don’t really want the hole, either: they want to install their bookshelves. Why not develop methods that don’t require holes? Or perhaps that don’t required bookshelves. (e-books)
Declarative memory / Procedural memory
Both the positive, relaxed state and the anxious, negative, and tense state are valuable and powerful tools for human creativity and action. The extreme of both states, however, can be dangerous.
Three levels of Processing: Visceral, Behavioral, and Reflective. Visceral and behavioral levels are subconscious and the home of basic emotions. The reflective level is where conscious thought and decision-making reside, as well as the highest level of emotions.
The visceral level is tightly coupled to the body’s musculature - the motor system.
Visceral responses are fast and completely subconscious. For designers, the visceral response is about immediate perception: the pleasantness of a mellow, harmonious sound or the jarring, irritating scratch of fingernails on a rough surface.
The behavioral level is the home of learned skills, triggered by situations that match the appropriate patterns. For designers, the most critical aspect of the behavioral level is that every action is associated with an expectation.
Advertisers hope that the strong reflective value associated with a well-known, highly prestigious brand might overwhelm our judgement, despite a frustrating experience in using the product. Vacations are often remembered with fondness, despite the evidence from diaries of repeated discomfort and anguish.
One important emotional state is the one that accompanies complete immersion into an activity, a state that the social scientist Mihaly CSIKSZENMIHALYI has labeled “flow.”
The flow state occurs when the challenge of the activity just slightly exceeds our skill level, so full attention is continually required. Flow requires that the activity be neither too easy nor too difficult relative to our level of skill.
The vicious cycle starts: if you fail at something, you think it is your fault. Therefore, you think you can’t do that task. As a result, next time you have to do the task, you believe you can’t, so you don’t even try. The result is that you can’t, just as you thought. You’re trapped in a self-fulfilling prophecy.
People are not machines. Machines don’t have to deal with continual interruptions. People are subjected to continual interruptions. As a result, we are often bouncing back and forth between tasks, having to recover or place, what we were doing, and what we were thinking when we return to a previous task. No wonder we sometimes forget our place when we return to the original task, either skipping or repeating a step, or imprecisely retaining the information we were about to enter.
Our strengths are in our flexibility and creativity, in coming up with solutions to novel problems. We are creative and imaginative, not mechanical and precise. Machines require precision and accuracy; people don’t. And we are particularly bad at providing precise and accurate inputs. So why are we always required to do so? Why do we put the requirements of machines above those of people?
When people interact with machines, things will not always go smoothly. This is to be expected. So designers should anticipate this. It is easy to design devices that work well when everything goes as planned. The hard and necessary part of design is to make things work well even when things do not go as planned.
The seven stages of action: seven fundamentals design principles
In general, each stage of action requires its own special design strategies and, in turn, provides its own opportunity for disaster.
7 stages of action :
-1 What do I want to accomplish?
-2 What are the alternative action sequences?
-3 What action can I do now?
-4 How do I do it?
-5 What happened?
-6 What does it mean?
-7 Is this okay? Have I accomplished my goal?
7 design principles :
-1 Discoverability. It is possible to determine what actions are possible and the current state of the device.
-2 Feedback. There is full continuous information about the results of actions and the current state of the product or service. After an action has been executed, it is easy to determine the new state.
-3 Conceptual model. The design projects all the information needed to create a good conceptual model of the system, leading to understanding and a feeling of control. The conceptual model enhances both discoverability and evaluation of results.
-4 Affordances. The proper affordances exist to make the desired actions possible.
-5 Signifiers. Effective use of signifiers ensures discoverability and that the feedback is well communicated and intelligible.
-6 Mappings. The relationship between controls and their actions follows the principles of good mapping, enhanced as much as possible through spatial layout and temporal contiguity.
-7 Constraints. Providing physical, logical, semantic, and cultural constraints guides actions and eases interpretation.
One of my self-imposed rules is, “Don’t criticize unless you can do better.” Try to understand how the faulty design might have occurred: try to determine how it could have been done otherwise.
The partnership of technology and people makes us smarter, stronger, and better able to live in the modern world. We have become reliant on the technology and we can no longer function without it. When things work, we are informed, comfortable, and effective. When things break, we may no longer be able to function. This dependence upon technology is very old, but every decade the impact covers more and more activities.
Natural mappings are those where the relationship between the controls and the object to be controlled is obvious. Here are three levels of mapping:
-Best mapping: controls are mounted directly on the item to be controlled.
-Second-best mapping: controls are as close as possible to the object to be controlled.
-Third-best mapping: controls are arranged in the same spatial configuration as the objects to be controlled.
Four kings of constraints: Physical, Cultural, Semantic, and Logical
Physical constraints: why not design a battery with which it would be impossible to make an error: use physical constraints so that the battery will fit only properly oriented. Alternatively, design the battery or the electrical contacts so that orientation doesn’t matter.
Cultural constraints are likely to change with time. (e.g. colors of the firefighter lights)
Activity-centered controls:
A related but wrong approach is to be device-centered rather than activity-centered.
Many auditoriums have computer-based controls: video requires a dark auditorium plus control of sound level and controls to start, pause, and stop the presentation. Projected images require a dark screen area with enough light in the auditorium so people can take notes. Lecture requires some stage light so the speaker can be seen.
Conventions are cultural constraints.
When all else fails, standards are the way to proceed.
Sounds should convey something about the actions that are taking place, actions that matter to the user but that would otherwise not be visible. The buzzes, clicks, and hums that you hear while a telephone call is being completed are one good example: take out those noises and you are less certain that the connection is being made.
Sound is tricky. It can annoy and distract as easily as it can aid.
Skeuomorphic is the technical term for incorporating old, familiar ideas into new technologies, even though they no longer play a functional role. Early plastics were design to look like wood; folders in computer file systems often look the same as paper folders, complete with tabs. One way of overcoming the fear of the new is to make it look like the old.
Principles for the design of sounds of electric vehicles:
-1 Alerting. The sound will indicate the presence of an electric vehicle.
-2 Orientation. The sound will make it possible to determine where the vehicle is located, a rough idea of its speed, and whether it is moving toward or away from the listener.
-3 Lack of annoyance.
-4 Standardization versus individualization. Standardization is necessary to ensure that all electric vehicle can readily be interpreted. If they vary too much, novel sounds might confuse the listener.
“We caught the (human) culprit”. The same error will occur over and over again. Instead, when an error happens, we should determine why, then redesign the product or the procedures being followed so that it will never occur again or, if it does, so that it will have minimal impact.
Root cause analysis is the name of the game: investigate the accident until the single, underlying cause is found. What this ought to mean is that when people have indeed made erroneous decisions or actions, we should determine what cause them to err. This is what root cause analysis ought to be about. Alas, all too often it stops once a person is found to have acted inappropriately. (eg. Chernobyl TV show scene where the scientist explains what happened)
“Five Whys,” originally developed by Sakichi TOYODA and used by the Toyota Motor Company as part of the Toyota Production System for improving quality. This procedure emphasizes the need to keep going even after a reason has been found.
Why do people err? Because the designs focus upon the requirements of the system and the machines, and not upon the requirements of people.
In some cases, the only way to complete a job might be to violate a rule or procedure.
Two types of Errors: Slips and Mistakes
A slip occurs when a person intends to do one action and ends up doing something else (action-based: putting the hot coffee in the fridge instead of the milk, memory-lapse: forgot to turn off the gas burner).
A mistake occurs when the wrong goal is established, or the wrong plan is formed (rule-based, knowledge-based: using pounds instead of kilograms, and memory-lapse: distracted worker forgot to complete a step).
Designers need to avoid procedures that have identical opening steps but then diverge. Whenever possible, sequences should be designed to differ from the very start.
Designers must try to avoid modes, but if they are necessary, the equipment must make it obvious which mode is invoked. Once again, designers must always compensate for interfering activities.
To understand human error, it is essential to understand social pressure.
Checklists: It is always better to have two people do checklists together as a team: one to read the instruction, the other to execute it. When two people are involved, a junior person (in aviation, the first officer) is being asked to watch over the action of the senior person. This is a strong violation of the lines of authority in many cultures.
Many people who object to checklists are actually objecting to badly designed lists: designing a checklist for a complex task is best done by professional designers in conjunction with subject matter experts.
Reporting errors: the only way to reduce the incidence of errors is to admit their existence, to gather together information about them, and thereby to be able to make the appropriate changes to reduce their occurrence. In the absence of data, it is difficult or impossible to make improvements.
Designing for Error: It is relatively easy to design for the situation where everything goes well, where people use the device in the way that was intended, and no unforeseen events occur. The tricky part is to design for when things go wrong.
-Understand the causes of error and design to minimize those causes.
-Do sensibility checks. Does the action pass the “common sense” test?
-Make it possible to reverse action – to “undo” them – or make it harder to do what cannot be reversed.
-Make it easier for people to discover the errors that do occur, and make them easier to correct.
-Don’t treat the action as an error; rather, try to help the person complete the action properly. Think of the action as an approximation to what is desired.
To resume, it is necessary to remember precisely the previous state of the activity: what the goal was, where one was in the action cycle, and the relevant state of the system.
Electronic systems have a wide range of methods that could be used to reduce error. One is to segregate controls, so that easily confused controls are located far from one another. Another is to use separated modules, so that any control not directly relevant to the current operation is not visible on the screen, but requires extra effort to get to.
Perhaps the most powerful tool to minimize the impact of errors is the Undo command.
People are flexible, versatile, and creative. Machines are rigid, precise, and relatively fixed in their operation. There is a mismatch between the two, one that can lead to enhanced capability if used properly.
Make actions reversible, make errors less costly. Here are key design principles:
-Put the knowledge required to operate the technology, in the world. Don’t require that all the knowledge must be in the head. Allow for efficient operation when people have learned all the requirements, when they are experts who can perform without the knowledge in the world, but make it possible for non-experts to use the knowledge in the world. This will also help experts who need to perform a rare, infrequently performed operation or return to the technology after a prolonged absence.
-Use the power of natural and artificial constraint: physical, logical, semantic, and cultural. Exploit the power of forcing functions and natural mappings.
-Make things visible, both for execution and evaluation. One the execution side, provide feedforward information: make the options readily available. On the evaluation side, provide feedback: make the results of each action apparent. Make it possible to determine the system’s status readily, easily, accurately, and in a form consistent with the person’s goals, plans, and expectations.
We should deal with error by embracing it, by seeking to understand the causes and ensuring they do not happen again. We need to assist rather than punish or scold.
Human-centered design (HCD) is the process of ensuring that people’s needs are met, that the resulting product is understandable and usable, that is accomplishes the desired tasks, and that the experience of use is positive and enjoyable.
The Double-Diamond Model of Design:
Finding the right problem (then) Finding the right solution
Start with an idea, and through the initial design research, expand the thinking to explore the fundamental issues. Only then is it time to converge upon the real, underlying problem. Similarly, use design research tools to explore a wide variety of solutions before converging upon one.
The iterative cycle of HCD: Make observations on the intended target population, generate ideas, produce prototypes and test them. Repeat until satisfied.
There is nothing like a firm deadline to get creative minds to reach convergence.
One of its most critical techniques is to observe the would-be customers in their natural environment, in their normal lives, wherever the product or service being designed will actually be used.
We need both (design and marketing). Designers understand what people really need. Marketing understands what people actually buy. These are not the same things, which is why both approaches are required: marketing and design researchers should work together in complementary teams. If nobody buys the product, then all else is irrelevant.
Idea generation:
-Generate numerous ideas. It is dangerous to become fixated upon one or two ideas too early in the process.
-Be creative without regard for constraints. Avoid criticizing ideas, whether your own or those of others. Even crazy ideas, often obviously wrong, can contain creative insights that can later be extracted and put to good use in the final idea selection. Avoid premature dismissal of ideas.
-Question everything. I am particularly fond of “stupid” questions. A stupid question asks about things so fundamental that everyone assumes the answer is obvious.
Testing: how many people should be studied? Opinions vary, nut as my association, Jakob Nielsen, has long championed the number five: five people studied individually. Then, study the results, refine them, and do another iteration, testing five different people. Five is usually enough to give major findings.
How can we pretend to accommodate all of these very different, very disparate people? The answer is to focus on the activities, not the individual person. I call this activity-centered design. Let the activity define the product and its structure. Let the conceptual model of the product be built around the conceptual model of the activity.
Focusing upon tasks is too limiting. Apple’s success with its music player, the iPod, was because Apple supported the entire activity involved in listening to music: discovering it, purchasing it, getting it into the music player, developing playlists (that could be shared), and listening to the music. Apple’s success was due to its combination of two factors: brilliant design plus support for the entire activity of music enjoyment.
Design for individuals and the results may be wonderful for the particular people they were designed for, but a mismatch for others. Design for activities and the result will be usable by everyone.
Delay precise specification of the product requirements until some iterative testing with rapidly deployed prototypes has been done, while still keeping tight control over schedule, budget, and quality.
Market-driven pressures plus an engineering-driven company yield every-increasing features, complexity, and confusion,
Don Norman’s law of product development: The day a product development process starts, it is behind schedule and above budget.
Patents create a minefield for designers and engineers, for today it is almost impossible to design or build anything that doesn’t conflict with patents, which means redesign to work one’s way through the mines.
The clash of disciplines can be resolved by multidisciplinary teams whose participants learn to understand and respect the requirements of one another. Multidisciplinary teams allow for enhanced communication and collaboration, often saving both time and money.
Product have multiple, conflicting requirements: designers need to understand their customers, and in many cases, the customer is the person who purchases the product, not the person who actually uses it. It is just as important to study those who do the purchasing ass it is to study those who use it.
Designing for special people: Most people do not wish to advertise their infirmities. Actually, many people do not wish to admit having infirmities, even to themselves.
Most of these devices are ugly. They cry out, “Disability here.” Why not transform them into products to be proud of?
Sam Farber (and his company OXO) wanted to develop a vegetable peeler that his arthritic wife could use. Vegetable peelers used to be an inexpensive simple metal tool, awkward to use, painful to use and not even that effective at peeling. Even though the new peeler was designed for someone with arthritis, it was advertised as a better peeler for everyone.
Special features made for people with special needs often turn out to be useful for a wide variety of people.
Complexity is good; It is confusion that is bad: someone else’s kitchen looks complicated and confusion, but your own kitchen does not.
Standards are necessary: (cf. the nonstandard clock)
Why was the HDTV aspect ratio set at 16:9 (or 1:8) if no movies used that ratio? Because engineers liked it: square the old aspect ratio of 4:3 and you get the new one, 16:9.
In her book Different, Harvard professor Youngme Moon argues that it is this attempt to match the competition that causes all products t be the same. When companies try to increase sales by matching every feature of their competitors, they end up hurting themselves. After all, when products from two companies match feature by feature, there is no longer any reason for a customer to prefer one over another.
The best products come from ignoring these competing voices and instead focusing on the true needs of the people who use the product. Jeff Bezos, the founder and CEO of Amazon, calls his approach “customer obsessed.”
I predict that although we will still talk with one another over a distance, we will not have any device called a telephone in the twenty-second century.
Name an industry or an activity and if it hasn’t been transformed by new technologies, it will be.
Ideas take a long time to traverse the distance from conception to successful product.
Two forms of Innovation: Incremental and Radical – one follows a natural, slow evolutionary process; the other is achieved through radical new development. In general, people tend to think of innovation as being radical, major changes, whereas the most common and powerful form of it is actually small and incremental.
The design of everyday things is in great danger of becoming the design of superfluous, overloaded, unnecessary things.
Design is successful only if the final product is successful – if people buy it, use it, and enjoy it thus spreading the word. A design that people do not purchase is a failed design, no matter how great the design team might consider it.