The Design of Everyday Things Summary

04 Jan 2024 in Posts

Photo Credits: supremo.co.uk.

Here are my notes and quotes on The Design of Everyday Things by Don Norman. My notes are casual and include what I believe are the essential concepts, ideas, and insights from the book, along with direct quotes from the author:

• This book covers everyday things, focusing on the interplay between technology and people to ensure that the products actually fulfill human needs while being understandable and usable.

• The products should also be delightful and enjoyable, which means that not only must the requirements of engineering, manufacturing, and ergonomics be satisfied, but attention must be paid to the entire experience, which means the aesthetics of form and the quality of interaction.

• Much of the design is done by engineers who are experts in technology but limited in their understanding of people. “We are people ourselves,” they think, “so we understand people.” But in fact, we humans are amazingly complex. Those who have not studied human behavior often think it is pretty simple. Engineers, moreover, make the mistake of thinking that logical explanation is sufficient: “If only people would read the instructions,” they say, “everything would be all right.” Engineers are trained to think logically.

• Design is concerned with how things work, how they are controlled, and the nature of the interaction between people and technology. When done well, the results are brilliant, pleasurable products. When done badly, the products are unusable, leading to great frustration and irritation.

• Good design starts with an understanding of psychology and technology. 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. Designers need to focus their attention on the cases where things go wrong, not just on when things work as planned (…). The understanding comes about primarily through observation, for people themselves are often unaware of their true needs, even unaware of the difficulties they are encountering. Getting the specification of the thing to be defined is one of the most difficult parts of the design, so much so that the HCD principle is to avoid specifying the problem as long as possible but instead to iterate upon repeated approximations. This is best done through rapid test of ideas, and after each test modifying the approach and the problem definition.

• Good design requires consideration of the entire system to ensure that the requirements, intentions, and desires at each stage are faithfully understood and respected at all the other stages.

• Experience is critical, for it determines how fondly people remember their interactions.

• Physical limitations are well understood by designers; mental limitations are greatly misunderstood. 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.

• When people err, change the system so that type of error will be reduced or eliminated. When complete elimination is not possible, redesign to reduce the impact.

• 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.

• Simplified models are the key to successful application.

• Make memory unnecessary: put the required information in the world. Even systems that do not use menus need to provide some structure: appropriate constraints and forcing functions, natural good mapping, and all the tools of feedforward and feedback. The most effective way of helping people remember is to make it unnecessary.

• The choice of metaphor dictates the proper design for interaction.

• The design difficulties occur when there is a switch in metaphors.

• Complexity is essential, confusion is undesirable.

• Most things are intended to be easy to use, but aren’t. But some things are deliberately difficult to use—and ought to be.

• With massive change, a number of fundamental principles stay the same. Human beings have always been social beings. Social interaction and the ability to keep in touch with people across the world, across time, will stay with us. The design principles of this book will not change, for the principles of discoverability, offeedback, and of the power of affordances and signifiers, mapping, and conceptual models will always hold. Even fully autonomous, automatic machines will follow these principles for their interactions. Our technologies may change, but the fundamental principles of interaction are permanent.

  Key Terms

• 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?

• Human-Centered design is a design philosophy. It means starting with a good understanding of people and the needs that the design is intended to meet. This understanding comes about primarily through observation, for people themselves are often unaware of their true needs, even unaware of the difficulties they are encountering. Getting the specification of the thing to be defined is one of the most difficult parts of the design, so much so that the HCD principle is to avoid specifying the problem as long as possible but instead to iterate upon repeated approximations. This is done through rapid tests of ideas, and after each test modifying the approach and the problem definition. The results can be products that truly meet the needs of people.

• The Double-Diamond Model of Design: 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 double-diamond describes the two phases of design: finding the right problem and fulfilling human needs.
  • The Iterative Cycle of Human-Centered Design: make observations on the intended target population, generate ideas, produce prototypes and test them. Repeat until satisfied. This is often called the spiral method, to emphasize that each iteration through the stages makes progress.
• Discoverability results from appropriate application of five fundamental psychological concepts:
  • Affordances: relationship between the properties of an object and the capabilities of the agent that determines just how the object could possibly be used.
  • Signifiers: communicate where the action should take place. Good design requires, among other things, good communication of the purpose, structure, and operation of the device to the people who use it.
  • Constraints: providing physical, logical, semantic, and cultural constraints guides actions and eases interpretation.
  • Mapping: relationship between controls and their actions. 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.
  • Feedback: communicating the results of an action. Feedback must be immediate, informative and poor feedback can be worse than no feedback at all. Feedback is essential but not when it gets in the way of others things, including a calm and relaxing environment.

• Conceptual Models: an explanation, usually highly simplified, of how something works. It doesn’t have to be complete or even accurate as long as its useful. Good conceptual models are the key to understandable, enjoyable products: good communication is the key to good conceptual models.

• Forcing functions: a form of physical constraint. Situations in which the actions are constrained so that failure at one stage prevents the next step from happening.
  • Interlocks: forces operations to take place in proper sequence.
  • Lock-In: keeps an operation active, preventing someone from prematurely stopping it.
  • Lockouts: prevents someone from entering a space that is dangerous, or prevents an event from occurring.
• 7 Stages of Action:
  • Goal (form the goal) - what do I want to accomplish?
  • Plan (the action) - What are the alternative action sequences?
  • Specify (an action sequence) - What action can I do now?
  • Perform (the action sequence) - How do I do it?
  • Perceive (the state of the world) - What happened?
  • Interpret (the perception) - What does it mean?
  • Compare (the outcome with the goal) - Is this okay? Have I accomplished my goal?
• 3 Levels of Processing (useful approximate model of human cognition and emotion):
  • Visceral (lizard brain)
  • Behavioral (learned but subconscious skills)
  • Reflecetive (conscious cognition)

Design must take place at all 3 levels - do not blame people when they fail to use your products correctly, take people’s difficulties as signifiers as to how to improve, eliminate all error messages and replace with help and guidance messages, make it possible to correct problems directly from help and guidance messages, assume that what people have done is partially correct, think positively.

• Root cause analysis: investigate the accident until the single, underlying cause is found.

• Five Whys: when searching for the reason, even after you have found one, do not stop: ask why that was the case. And then ask why again. Keep asking until you have uncovered the true underlying cause.

• Two types of errors:
  • Slips: a person intends to do one action and ends up doing something else.
    • Slips most frequently occur when the conscious mind is distracted. One way to minimize slips is to ensure that people always pay close, conscious attention to the acts being done.
    • The best way of mitigating slips is to provide perceptible feedback about the nature of the action being performed, then very perceptible feedback describing the new resulting state, coupled with a mechanism that allows the error to be undone.
    • There are two major classes of slips: action-based and memory-lapse. In action-based slips, the wrong action is performed. In lapses, memory fails, so the intended action is not done or its results not evaluated. Action-based slips and memory lapses can be further classified according to their causes.
    • Mode-error slips: a mode error occurs when a device has different states in which the same controls have different meanings.
  • Mistakes: occurs when the wrong goal is established or the wrong plan is formed.
    • To understand human error, it is essential to understand social pressure.
• Many systems compound the problem by making it easy to err but difficult or impossible to discover error or to recover from it. It should not be possible for one simple error to cause widespread damage. Here is what should be done:
  • 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 actions—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.
• Adding constraints to block errors:
  • Perhaps the most powerful tool to minimize the impact of errors is the Undo command in modern electronic systems.
  • Many systems try to prevent errors by requiring confirmation before a command will be executed, especially when the action will destroy something of importance.
  • Electronic systems have another advantage over mechanical ones: they can check to make sure that the requested operation is sensible.

• The best solution to the problem of designing for everyone is flexibility: flexibility in the size of the images on computer screens, in the sizes, heights, and angles of tables and chairs. Allow people to adjust their own seats, tables, and working devices. Allow them to adjust lighting, font size, and contrast. Flexibility on our highways might mean ensuring that there are alternative routeswith different speed limits. Fixed solutions will invariably fail with some people; flexible solutions at least offer a chance for those with different needs.

• Cognition and emotion are tightly intertwined, which means that the designers must design with both in mind.

• Precise behavior can emerge from imprecise knowledge for four reasons:
  • Knowledge is both in the head and in the world.
  • Great precision is not required.
  • Natural constraints exist in the world.
  • Knowledge of cultural constraints and conventions exists in the head.
• Natural mappings are those where the relationship between the controls and the object to be controlled. Depending upon circumstances, natural mappings will employ spatial cues. Here are three levels of mapping, arranged in decreasing effectiveness as memory aids:
  • 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.
• The unaided mind is surprisingly limited. It is things that make us smart. Take advantage of them. Pilots use three major techniques:
  • They write down the critical information.
  • They enter it into their equipment as it is told to them, so minimal memory is required.
  • They remember some of it as meaningful phrases.

• Consistency in design is virtuous. It means that lessons learned with onesystem transfer readily to others. On the whole, consistency is to be followed. If a new way of doing things is only slightly better than the old, it is better to be consistent. But if there is to be a change, everybody has to change. Mixed systems are confusing to everyone. When a new way of doing things is vastly superior to another, then the merits of change outweigh the difficulty of change. Just because something is different does not mean it is bad. If we only kept to theold, we could never improve.

• Standardization is indeed the fundamental principle of desperation: when no other solution appears possible, simply design everything the same way, so people only have to learn once. The standards should reflect the psychological conceptual models, not the physical mechanics:
  • Skeuomorphic: incorporating old, familiar ideas into new technologies, even though they no longer play a functional role. One way of overcoming the fear of the new is to make it look like the old.
  • Standardization is one type of cultural constraint. With standardization, once you have learned to drive one car, you feel justifiably confident that you can drive any car, anyplace in the world. Standardization provides a major breakthrough in usability.

• Checklists are powerful tools, proven to increase the accuracy of behavior and toreduce error, particularly slips and memory lapses. They are especially importantin situations with multiple, complex requirements, and even more so where thereare interruptions. With multiple people involved in a task, it is essential that thelines of responsibility be clearly spelled out. It is always better to have twopeople do checklists together as a team: one to read the instruction, the other toexecute it. If, instead, a single person executes the checklist and then, later, asecond person checks the items, the results are not as robust. The personfollowing the checklist, feeling confident that any errors would be caught, mightdo the steps too quickly. But the same bias affects the checker. Confident in theability of the first person, the checker often does a quick, less than thorough job.

• One paradox of groups is that quite often, adding more people to check atask makes it less likely that it will be done right. Why? Well, if you wereresponsible for checking the correct readings on a row of fifty gauges anddisplays, but you know that two people before you had checked them and thatone or two people who come after you will check your work, you might relax,thinking that you don’t have to be extra careful. After all, with so many peoplelooking, it would be impossible for a problem to exist without detection. But ifeveryone thinks the same way, adding more checks can actually increase thechance of error. A collaboratively followed checklist is an effective way tocounteract these natural human tendencies.

• Swiss-Cheese Model:
  • Accidents usually have multiple causes, whereby had any single one of those causes not happened, the accident would not have occurred. The British accident researcher James Reason describes this through the metaphor of slices of Swiss cheese: unless the holes all line up perfectly, there will be no accident.
  • Two lessons: First, do not try to find “the” cause of an accident; Second, we can decrease accidents and make systems more resilient by designing them to have extra precautions against error (more slices of cheese)
  • Less opportunities for slips, mistakes, or equipment failure (less holes), and very different mechanisms in the different subparts of the system (trying to ensure that the holes do not line up).

• Resilience engineering: with the goal of designing systems, procedures, management, and the training of people so they are able to respond to problems as they arise. It strives to ensure that the design of all these things—the equipment, procedures, and communication both among workers and also externally to management and the public—are continually being assessed, tested, and improved.

• Don Norman’s Law of Product Development: The day a product development process starts, it is behind schedule and above budget.
  • The way to handle the time crunch that eliminates the ability to do good up-front design research is to separate that process from the product team: have design researchers always out in the field, always studying potential products and customers. Then, when the product team is launched, the designers can say, “We already examined this case, so here are our recommendations.” The same argument applies to market researchers.
• Even where a lack of usability or understandability is deliberate, it is still important to know the rules of understandable and usable design, for two reasons. First, even deliberately difficult designs aren’t entirely difficult. Usually there is one difficult part, designed to keep unauthorized people from using the device; the rest of it should follow the normal principles of good design. Second, even if your job is to make something difficult to do, you need to know how togo about doing it. In this case, the rules are useful, for they state in reverse just how to go about the task. You could systematically violate the rules like this:
  • Hide critical components.
  • Use unnatural mappings.
  • Make the actions physically difficult to do.
  • Require precise timing and physical manipulation.
  • Do not give any feedback.

• In every successful product there lurks the carrier of an insidious disease called “featuritis,” with its main symptom being “creeping featurism.”

• 2 forms of innovation: radical, incremental
  • Incremental: follows a natural, slow evolutionary process.
  • Radical: is achieved through radical new development.

• The clash of disciplines can be resolved by multidisciplinary teams whose participants learn to understand and respect the requirements of one another. Good product development teams work as harmonious groups, with representatives from all the relevant disciplines present at all times. If all the viewpoints and requirements can be understood by all participants, it is often possible to think of creative solutions that satisfy most of the issues. Note thatworking with these teams is also a challenge. Everyone speaks a different technical language. Each discipline thinks it is the most important part of the process. Quite often, each discipline thinks the others are stupid, that they are making inane requests. It takes a skilled product manager to create mutual understanding and respect. But it can be done.

• All technology can be used in ways never intended by the inventors. One exciting development is the rise of the small: efficient tools that empower individuals.

What I got out of it

This book has really changed the way I perceive good and bad design because it presents some very thought-provoking key terms and ideas. Although it may seem a bit dated, the information presented in it is timeless, so I highly recommend it to anyone who wants to learn how to think like a designer.

Related Resources

Here is a list of books and websites mentioned in The Design of Everyday Things, which might be helpful for further learning:

• “Designing Interactions” (2007) - Bill Moggridge
• “Designing Media” (2010) - Bill Moggridge
• “Ecosystem of Innovation: The History of Silicon Valley Design” (2014) - Barry Katz
• “Design: History, Theory, and Practice of Product Design” (2005) - Bernhard Bürdek
• “Change by Design” (2009) - Tim Brown and Barry Katz
• “Hidden in Plain Sight” (2013) - Jan Chipchase and Simon Steinhardt
• “Contextual Design: Defining Customer-Centered Systems” (1998) - Hugh Beyer and Karen Holtzblatt
• “Sketching User Experience: Getting the Design Right and the Right Design” (2007) - W. Buxton
• “Watches Tell More Than Time: Product Design, Information, and the Quest for Elegance” (2003) - D. Coates
• “About Face 3: The Essentials of Interaction Design” (2007) - A. Cooper, R. Reimann, D. Cronin
• “Experience Design: Technology for All the Right Reasons” (2010) - M. Hassenzahl
• Interaction Design Foundation.
• SIGCHI: The Computer-Human Interaction Special Interest Group for ACM.