The Design of Everyday Things by Donald Norman

Key Takeaways

Design is concerned with how things work, how they are controlled, and the nature of the interaction between people and technology
Key Design Terms
1. Discoverability - is it possible to even figure out what actions are possible and where and how to perform them? Discoverability results from appropriate application of five fundamental psychological concepts
  1. Affordances - relationship between a physical object and a person, the relationship between the properties of an object and the capabilities of the agent that determines just how the object could possibly be used. An affordance is a relationship
  2. Signifiers - signifiers communicate where the action should take place. Good communication of the purpose, structure, and operation of the device to the people who use it
  3. Constraints - providing physical, logical, semantic, and cultural constraints guides actions and eases interpretation
  4. Mapping - the relationship between the elements of two sets of things
    1. Best mapping - controls are mounted directly on the item to be controlled
    2. Second best - controls are as close as possible to the object to be controlled
    3. Third best - controls are arranged in the same spatial configuration of as the objects to be controlled
  5. Feedback - communicating the results of an action. Must be immediate 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
2. Understanding - what does it all mean? How is the product supposed to be used? What do all the different controls and settings mean
3. 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
4. Forcing Function - failure at one stage prevents the next stage from happening. Many errors stem from interruption
  1. Interlocks - forces operations to take place in proper sequence
  2. Lock-In - Keeps an operation active, preventing someone from prematurely stopping it. (happens with ERP for example, confusion comes in when trying to switch which leads to lock-in for the current system)
  3. Lockouts - prevents someone from entering a space that is dangerous, or prevents an event from occurring.
Human Centered Design
1. An approach that puts human needs, capabilities, and behaviors first, then designs to accommodate those needs, capabilities, and ways of behaving. The process of ensuring that people's needs are met, that the resulting product is understandable and usable, that it accomplishes the desired tasks, and that the experience of use is positive and enjoyable. Solving the right problem, and doing so in a way that meets human needs and capabilities
2. 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,w hat 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
3. 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. This has become known as the Double-Diamond Model of Design. It describes two phases of design: finding the right problem (discover) and fulfilling human needs (design): observation, idea generation, prototyping, testing
  1. Testing: five people studied individually is a great starting point. Then, study the results, refine them, and do another iteration, testing five different people. Five is usually enough to give major findings. And if you really want to test many more people, it is far more effective to do one test of five, use the results to improve the system, and then keep iterating the test-design cycle until you have tested the desired number of people. This gives multiple iterations of improvement, rather than just one.
7 Stages of Action
1. Goal (form the goal) - what do I want to accomplish?
2. Plan (the action) - What are the alternative action sequences?
3. Specify (an action sequence) - What action can I do now?
4. Perform (the action sequence) - How do I do it?
5. Perceive (the state of the world) - What happened?
6. Interpret (the perception) - What does it mean?
7. Compare (the outcome with the goal) - Is this okay? Have I accomplished my goal?
8. The insights from the 7 stages of action lead us to 7 fundamental principles of design
  1. Discoverability
  2. Feedback
  3. Conceptual Model
  4. Affordances
  5. Signifiers
  6. Mappings
  7. Constraints
3 Levels of Processing
1. Visceral (lizard brain)
2. Behavioral (learned but subconscious skills)
3. Reflecetive (conscious cognition)
4. 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
Bad Design
1. Physical limitations are well understood but mental limitations are greatly misunderstood
2. 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
3. Root cause Analysis - investigate the accident until the single, underlying cause is found.
4. 5 Why's - 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
5. 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
6. Two types of errors
  1. Slips - person intends to do one action and ends up doing something else. Slips frequently occur when the conscious mind is distracted so, one way to reduce slips is to ensure that people always pay close attention to the acts being done. 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
    1. Action-based - wrong action is performed
    2. Memory-lapse - intended action is not done or its results not evaluated
    3. Mode-Error - when a device has different states in which the same controls have different meanings
  2. Mistakes - when the wrong goal is established or the wrong plan is formed
7. To understand human error, it is essential to understand social pressure (time, psychological, and economic forces)
8. The trickiest and most important part is to design for when things go wrong
  1. Understand the causes of error and design to minimize those causes
  2. Do sensibility checks. Does the action pass the "common sense' test?
  3. Make it possible to reverse the actions - to "undo" them - or make it harder to do what cannot be reversed
  4. Make it easier for people to discover the errors that do occur, and make them easier to correct
  5. 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
9. Add constraints to block errors
10. Perhaps the most powerful tool to minimize the impact of errors is the Undo command in modern electronic systems
11. Confirmation and error messages
12. Sensibility checks
Other
1. Focus on interplay of technology and people to ensure that the products fulfill human needs while being understandable and usable. Ideally delightful and enjoyable too
2. Why flaws? Much of design is done by engineers who are experts in technology but not of people. Have to accept the way humans behave and not how we wish it to be
3. The best solution to the problem of designing for everyone is flexibility: flexibility is 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
4. Cognition and emotion are highly intertwined - must keep both in mind at all times
5. 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 other stages.
6. Precise behavior can emerge from imprecise knowledge for reasons
  1. Knowledge is both in the head and in the world
  2. Great precision is not required
  3. Natural constraints exist in the world
  4. Knowledge of cultural constraints and conventions exist in the head
7. Simplified models are the key to successful application
8. Make something too secure and it becomes insecure (people use post its to remind them of passwords they have to change all the time)
9. Solve problems by interpreting, find natural mappings. Make memory unnecessary by putting the required information in the world. Appropriate constraints and forcing functions, natural good mapping, and all the tools of feedback and feedforward. The most effective way of helping people remember is to make it unnecessary. The unaided mind is surprisingly limited. It is things that make us smart. Take advantage of them. Pilots:
  1. Write down critical information
  2. Enter it into their equipment as its told to them, so minimal memory is required
  3. They remember some of it as meaningful phrases
10. Counter-intuitive bike model - to turn left, you first have to turn right. This is counter-steering and is necessary to get your balance and lean right before turning
11. Reminders - must have a signal and the message
12. A major obstacle is that often the purchaser is not the user
13. The choice of metaphor dictates the proper design for interaction. The design difficulties occur when there is a switch in metaphor
14. Consistency in design is virtuous. It means that lessons learned with one system 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.
15. Standardization is the fundamental principle of desperation: when no other solution appears possible, simply design everything the way way, so people only have to learn once. The standards should reflect the psychological conceptual models, not the physical mechanics.
  1. Skeumorphic - 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
  2. One type of cultural constraint, provides a major breakthrough in usability
16. Usage of sound as a signifier is important but tricky because you don't want to disturb people too much
17. Checklists are important and is way better to have two people do checklists together as a team: one to read the instruction, the other to execute it. If, instead, a single person executes the checklist and then, later a second person checks the items, the results are not as robust. The person following the checklist, feeling confident that any errors would be caught, might do the steps too quickly. But the same bias affects the checker. Confident in the ability 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 a task makes it less likely that it will be done right. A collaboratively followed checklist is an effective way to counteract these natural human tendencies.
18. Swiss-Cheese Model
  1. Accidents usually have multiple causes, whereby had any single one of those causes not happened, the accident would not have occurred. Like slices of Swiss cheese, unless the holes all line up perfectly, there will be no accident.
  2. Two lessons: 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 errors
  3. Well-designed systems are resilient against failure. Design redundancy and layers of defense
  4. Can prevent errors by adding more "slices of cheese", reduce the number of holes (or make the holes smaller), alert the human operators when several holes have lined up.
19. Resilience engineering - goal is to design systems, procedures, management, and the training of people so that they are able to respond to problems as they arise. It strives to ensure that the design of all these things - the equipment, procedure, and communication both among workers and also externally to management and the public - are continually being assessed, tested, and improved.
20. Norman's Law of Product Development - the day a product development process starts, it is behind schedule and above budget
  1. 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.
21. Complexity is essential, confusion is undesirable
22. Some things should be deliberately difficult to use - hide critical components, use unnatural mappings, make the actions physically difficult to do, require precise timing and physical manipulation, do not give any feedback
23. Beware "featuritis" - creeping add of features. Don't follow blindly, focus on your strengths and not weaknesses
24. Invention and adoption cycle - fast to be invented, slow to be accepted, even slower to fade away
25. 2 forms of innovation: radical, incremental
  1. Incremental - can also be thought of as hill-climbing. You take one step, assess if it is in the right direction, and keep doing this until you have reached a point where all steps would be downhill; then you are the the top of a hill, or at least at a local peak
  2. Radical - often driven by new technologies that make possible new capabilities. A second factor is the reconsideration of the meaning of technology
26. Most successful teams are a combination of human experts and computers. Weak human + machine + better process was superior to a strong computer alone and, more remarkably, to a strong human + machine + inferior process
27. Rise of the small - good design and technology empowers individuals. Today, anyone can create, design, and manufacture, opening doors that were closed in the past. Our technologies may change, but the fundamental principles of interaction are permanent.

What I got out of it

Outstanding book to better understand some of the key terms and ideas behind good and bad design - affordances, signifiers, mapping, constraints, feedback, feedforward...

Summary