The Design of Everyday Things

by Donald A. Norman

Good design is actually a lot 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.

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?

It is the duty of machines and those who design them to understand people. It is not our duty to understand the arbitrary, meaningless dictates of machines.

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.

Good design starts with an understanding of psychology and technology. Good design requires good communication, especially from machine to person,

Affordances determine what actions are possible. Signifiers communicate where the action should take place. We need both.

Feedback is essential, but not when it gets in the way of other things, including a calm and relaxing environment.

The idea that a person is at fault when something goes wrong is deeply entrenched in society. That’s why we blame others and even ourselves.

“Don’t criticize unless you can do better.”

Sometimes, bad products succeed and good products fail. The world is complex.

To maximize efficiency of working memory it is best to present different information over different modalities: sight, sound, touch (haptics), hearing, spatial location, and gestures.

A huge number of psychological experiments show how easy it is to implant false memories into people’s minds so convincingly that people refuse to admit that the memory is of an event that never happened.

Most things in the world have a sensible structure, which tremendously simplifies the memory task. When things make sense, they correspond to knowledge that we already have, so the new material can be understood, interpreted, and integrated with previously acquired material. Now we can use rules and constraints to help understand what things go together. Meaningful structure can organize apparent chaos and arbitrariness.

C = (°F–30) / 2

Approximate answers are often good enough, even if technically wrong.

almost always, a rough estimate is good enough. When precision is required, use a calculator.

Knowledge in the mind is ephemeral:

the behavior that is appropriate in one place is inappropriate in another, even in situations that appear to be identical. Known cultural norms can create comfort and harmony. Unknown norms can lead to discomfort and confusion.

People invariably object and complain whenever a new approach is introduced into an existing array of products and systems.

Consistency in design is virtuous. It means that lessons learned with one system transfer readily to others.

Root cause analysis is intended to determine the underlying cause of an incident, not the proximate cause.

The capture slip is defined as the situation where, instead of the desired activity, a more frequently or recently performed one gets done instead: it captures the activity.

In the slip known as a description-similarity slip, the error is to act upon an item similar to the target. This happens when the description of the target is sufficiently vague.

retrieval from long-term memory is actually a reconstruction rather than an accurate record. As a result, it is subject to numerous biases.

Once the mistaken diagnosis is made, all information from then on is interpreted from the wrong point of view.

adding more people to check a task makes it less likely that it will be done right.

The paradox is that automation can take over the dull, dreary tasks, but fail with the complex ones.

Good designers never start by trying to solve the problem given to them: they start by trying to understand what the real issues are. As a result, rather than converge upon a solution, they diverge, studying people and what they are trying to accomplish, generating idea after idea after idea.

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.

In theory, there is no difference between theory and practice. In practice, there is.

market-driven pressures plus an engineering-driven company yield ever-increasing features, complexity, and confusion.

it’s what is called the Zeitgeist, a German word meaning “spirit of the time.” In other words, the time was ripe, the ideas were “in the air.” The competition emerged even before we had delivered our first product. What

being first does not guarantee success.

The more things change, the more they are the same.