[notes] The Design of Everyday Things

The Design of Everyday Things (2002) by Donald A. Norman #

Buy from Amazon

NOTE: Bewarned, these notes are un-edited, un-revised, and un-styled. I plan on cleaning them up eventually, but until then, I apologize.

The Psychopathology of Everyday Things #

Discoverability: What actions are possible?

Understanding: How is the product supposed to be used?

Industrial design - professional service of creating and developing concepts and specifications that optimize the functional, value and appearance of products and systems for the mutual benefit of both the user and manufacturer

Interaction design - focuses on how people interact with technology

Experience design - practice of designing products, processes, services, events, and environments with a focus placed on the quality and enjoyment of the total experience

Interaction between people and machines is interesting:

Human-Centered Design (HCD)

Affordances: a relationship between an object and an agent that determines how the object can be used

Anti-affordance: preventing an agent from being able to use an object in a certain way

Signifiers: a communication of the existence and proper usage of an affordance

Affordances: the possible interactions between people and the environments

Perceived affordances: act as signifiers, but can be ambiguous

Signifiers: signal what actions are possible and how they should be done

Mapping: relationship between the elements of two sets of things

Feedback: communicating the results of an action

Conceptual Models: an explanation of how something works

“Good conceptual models are the key to understandable, enjoyable products: good communication is the key to good conceptual models.”

The Psychology of Everyday Actions #

When people try to do things they face the:

  1. Gulf of Execution - figuring out what to do to achieve what you want
  2. Gulf of Evaluation - figuring out what happened

The Seven Stages of Action #

  1. form the goal
  2. plan the action
  3. specify the action sequence
  4. perform the action sequence (state of the world changes)
  5. perceive the state of the world
  6. interpret the perception
  7. compare the outcome with the goal

Root cause analysis - a process for determining the root goal
“People don’t want to buy a quarter-inch drill. They want a quarter inch hole!” ~ Theodore Levitt

Human Thought: Mostly Subconscious #



“Emotion and cognition are tightly intertwined”

“Emotion interacts with cognition biochemically”

Three levels of processing

  1. Visceral
  2. makes quick judgements about the environment
  3. fast and completely subconscious
  4. sensitive only to the current state of things
  5. highly coupled to body’s musculature (we often determine our own body state by reading our musculature)
  6. causes animals to fight or flee
  7. for designers, this is about immediate perception
  8. every action is associated with an expectation (designers should use feedback to achieve this)
  9. Behavioral
  10. learned skills, triggered by situations that match the appropriate patterns
  11. we are often aware of the goal, but unaware of the details
  12. Reflective
  13. conscious cognition
  14. deep understanding, reasoning, and conscious decision making
  15. evaluates circumstance, actions and outcomes
  16. where highest levels of emotion take place (causes are assigned and predictions of the future take place)
  17. where blame and praise are assigned (where as a product might earn a recommendation to a friend)
  18. memories are more important than reality

“The stages of action can readily be associated with the three different levels of processing. At the lowest level are the visceral levels of calmness or anxiety when approaching a task or evaluating the state of the world. Then, in the middle level, are the behavioral ones driven by expectations on the execution side - for example, hope and fear - and emotions driven by the confirmation of those expectations on the evaluations side - for example, relief or despair. At the highest level are the reflective emotions, ones that assess the results in terms of the presumed causal agents and the consequences, both immediate and long term. Here is where satisfaction and pride occur, or perhaps blame and anger.”

Flow: complete immersion in an activity

Falsely blaming yourself #

Feedforward: the information that helps answer questions of execution

Feedback: aids in the understanding of what has happened

Seven fundamental principles of design

  1. Discoverability: It is possible to determine what actions are possible and the current state of the device.
  2. Feedback: There is full and 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 guides actions and eases interpretation.

Knowledge in the Head and in the World #

Precise Behavior from Imprecise Knowledge #


  1. Knowledge is both in the head and in the world
  2. we can derive knowledge from the structure of the world
  3. we embed knowledge by structuring the world around us
  4. Great precision is not required
  5. “Perfect behavior results if the combined knowledge in the head and in the world is sufficient to distinguish an appropriate choice from all others”
  6. Natural constraints exist in the world
  7. Knowledge of cultural constraints and conventions exists in the head
  8. abstract artificial constraints imposed by society

Constraints Simplify Memory #

e.g. - the powerful constraints of poetry for memorizing epics

Paradox: Security

The Structure or Working Memory #

Short-Term Working Memory

Long Term Memory

“The most effective way of helping people remember is to make it unnecessary.”

“Knowledge in the world, external knowledge, is a valuable tool for remembering, but only if it is available at the right place, at the right time, in the appropriate situation.”

Reminding: Prospective Memory #

Tradeoffs Between Knowledge in the World and in the Head #

Knowledge in the head

Knowledge in the world

Memory in Multiple Heads, Multiple Devices #

Natural Mappings #

Knowing What To Do: Constraints, Discoverability, and Feedback #

Constraints: constrain possible operations

Activity-Centered Controls #

Constraints that Force the Desired Behavior #

Forcing Functions: 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-Ins: keeps an operation active, preventing someone from prematurely stopping it (stopping it until desired operations have been done)

Lockouts: prevents someone from entering a space that is dangerous, or prevents an event from occurring

Conventions, Constraints, and Affordances #

“The interpretation of a perceived affordance is a cultural convention.”
“Conventions are a special kind of cultural constraint”

Human Error? No, Bad Design #

Root Cause Analysis #

Deliberate Violation #

Types of Errors #

Human error: deviance from “appropriate” behavior

  1. Slips: occurs when a person intends to do one action and ends up doing something else.
  2. action-based => wrong action was performed
  3. - capture slip => a situation where a more frequent or recently performed action gets performed instead of the desired action
  4. - “Designers should avoid procedures that have identical opening steps but then diverge.”
  5. - description-similarity slip => an error caused when the action is performed on the wrong item, usually one similar to the intended target
  6. - “This happens when the description of the target is sufficiently vague.”
  7. - mode-error slips => occurs when a device has different states in which the same controls have different meanings (we call these states modes)
  8. - especially likely when the equipment doesn’t make the mode visible
  9. memory lapse => intended action not done or results not evaluated
  10. tend to occur more frequently to skilled people than to novices because the skilled people tend to perform automatically under subconscious control

  11. Mistakes: occurs when the wrong goal is established or the wrong plan is formed

  12. person makes a poor decision, misclassifies a situation, or files to take all the relevant factors into account

  13. all following actions are part of the error because they follow an inappropriate intent

  14. rule-based => person has appropriately diagnosed the situation, but then decided upon an erroneous course of action (the wrong rule is being followed)

  15. knowledge-based => problem is misdiagnosed because or erroneous or incomplete knowledge

  16. memory-lapse => takes place when there is forgetting at the stages of goals, plans, or evaluation

Modes of behavior

Errors can be understood in reference to the seven stages of the action cycle

Checklists #

Reporting Error #

In Hindsight, Events Seem Logical #

Designing for Error #

“People are flexible, versatile, and creative. Machines are rigid, precise, and relatively fixed in their operations. There is a mismatch between the two that can lead to enhanced capability if used properly.”

Design Principles

The Swiss Cheese Model of How Errors Lead to Accidents #

When People Really Are at Fault #

Design Thinking #

“Designers are trained to discover the real problems.”

The Double Diamond Model of Design #

  1. find the right problem 1.1 discover (diverge) 1.2 define (converge)
  2. find the right solution 2.1 develop (diverge) 2.2 deliver (converge)

“How does the product manager keep the entire team on schedule despite the apparent random and divergent methods of designers? Encourage their free exploration, but hold them to the schedule (and budget) constraints).”

[deadline] “There is nothing like a firm deadline to get creative minds to reach convergence.”

Design Research vs Market Research #

Idea Generation (or ideation) #

Prototyping #

Testing #

Iteration #

Activity-Centered Design #

goals have three fundamental levels that control activities

  1. be-goals
  2. are the highest most abstract level and govern a person’s being
  3. determine why people act
  4. determine one’s self image
  5. do-goals
  6. determine the plans and actions to be performed for an activity
  7. motor goal
  8. tasks and operations

In the real world:

Don Norman’s Law of Product Development #

The Stigma Problem #

Complexity is Good; Confusion is Bad #

Standardization and Technology #

Deliberately Making Things Too Difficult #

Design in the World of Business #

Featuritis: A Deadly Temptation #

“Most companies compare features with their competition to determine where they are weak, so they can strengthen those area. Wrong, argues Moon. A better strategy is to concentrate on areas where they are stronger and to strengthen them even more. Then focus all marketing and advertisements to point out the strong points. This causes the product to stand our from the mindless her. As for the weaknesses, ignore the irrelevant ones, says Moon. The lesson is simple: don’t follow blindly; focus on strengths, not weaknesses. If the product has real strengths, it can afford to be food enough in the other areas.”

Two Forms of Innovation: Incremental and Radical #

Things That Make Us Smart #

“The power of the unaided mind is highly overrated. Without external aids, deep, sustained reasoning is difficult. Unaided memory, though, and reasoning are all limited in power. Human intelligence is highly flexible and adaptive, superb at inventing procedures and objects that overcome its own limits. The real powers come from devising external aids that enhance cognitive abilities… It is things that make us smart.”

Needless Features, Needless Models: Good for Business, Bad for the Environment #


Now read this


Part 1: I Promise This Is Going Somewhere # “The unexamined life is not worth living.” – Socrates The process of self-discovery is very similar to any process of scientific inquiry. We start by forming a hypothesis about ourself, which... Continue →