Good design is actually a lot harder to notice than poor design, in part because good designs fit out 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.
One prupose of this book is to give back of your control over the products in your life: to know how to select usable and understandable ones, to know how to fix those that aren't so usable or understandable.
To understand products, it is not enough to understand desing or technology: it is critical to understand business.
Two of the most important characteristics of good design:
1. Discoverability: Is it possible to even figure out what actions are possible and where and how to perform them?
2. Understanding: What does it all mean? How is the product supposed to be used? What do all the different controls and settings mean?
The major areas of design relevant to this book are:
1. Industrial design: The professional service of creating and developing concepts and specifications that optimize the function, value, and appearance of products and systems for the mutual benefit of both user and manufacturer (from the Industrial Design Society of America's website).
2. Interaction design: The focus is upon how people interact with technology. The goal is to enhance people's understanding of what can be done, what is happening, and what has just occurred. Interaction design draws upon principles of psychology, design, art and emotion to ensure a postive, enjoyable experience.
3. Experience design: The practice of designing products, processes, services, events, and enviroments with a focus placed on the quality and enjoyment of the total experience.
Engineers are designing for people the way they would like them to be, not for the way they really are. Even experts make errors, so we mush design our machines on the assumption that people will make errors.
Good design requires good communication, especially from machine to person, indicating what actions are possible, what is happening, and what is about to happen. Designers need to focus their attention on the cases where things go wrong, not just on when things work as planned.
1. Affordances: a relationship between the properties of an object and the capabilities of the agent that determine just how the object could possibly be used.
2. Signifiers: affordances determine what actions are possible. Signifiers communicate where the action should take place. Once I interpret a falg's motion to indicate wind direction, it does not matter why it was placed there.
Affordances represent the possibilities in the world for how an agent (a person, animal, or machine) can interact with something. Some affordances are perceivable, others are invisible.
Signifiers are signals. Some signifiers are signs, labels, and drawings placed in the world, such as the signs labeled "push", "pull", or "exit" on doors, or arrows and diagrams indicating what is to be acted upon or in which direction to gesture, or other instructions.
3. Mapping: the relationship between the elements of two sets of things. Note that there are many mappings that feel "natural" but in fact are specific to a particular culture: what is natural for one culture is not necessarily natural for another.
4. Feedback: some way of letting you know that the system is working on your request.
Poor feedback can be worse than no feedback at all, because it is distracting, uninformative, and in many cases irritating and anxiety-provoking. Too much feedback can be even more annoying than too little. Machines that give too much feedback are like backseat drivers. Too many announcements cause people to ignore all of them, or wherever possible, disable all of them.
5. Conceptual Model: an explanation, usually highly simplified, of how something works.
How do we form an appropriate conceptual model for the devices we interact with? We cannot talk to the designer, so we rely upon whatever information is available to us: what the device looks like, what we know from using similar things in the past, what was told to us in the sales literature, by salespeople and advertisements, by articles we may have read, by the product website and instruction manuals. I call the combined information available to us the system image.
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. This is the paradox of technology and the challenge for the designer.
Great design requires great designers, but that isn't enough: it also requires great management, because the hardest part of producing a product is coordinating all the many, separate disciplines, each with different goals and priorities.
usable and understandable / attractive / affordable / reliable / be able to be manufactured and serviced / distinguishable from competing products / superior in critical dimensions / Finally, people have to actually purchase it.