The Design of Everyday Things

To summarize: • Affordances are the possible interactions between people and the environment. Some affordances are perceivable, others are not. • Perceived affordances often act as signifiers, but they can be ambiguous. • Signifiers signal things, in particular what actions are possible and how they should be done. Signifiers must be perceivable, e

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

An affordance is a relationship between the properties of an object and the capabilities of the agent that determine just how the object could possibly be used.

The solution is human-centered design (HCD), an approach that puts human needs, capabilities, and behavior first, then designs to accommodate those needs, capabilities, and ways of behaving. Good design starts with an understanding of psychology and technology. Good design requires good communication, especially from machine to person, indicating w

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.

Communication is especially important when things go wrong. It is relatively easy to design things that work smoothly and harmoniously as long as things go right. But as soon as there is a problem or a misunderstanding, the problems arise. This is where good design is essential. Designers need to focus their attention on the cases where things go w

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?

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

To summarize: • Affordances are the possible interactions between people and the environment. Some affordances are perceivable, others are not. • Perceived affordances often act as signifiers, but they can be ambiguous. • Signifiers signal things, in particular what actions are possible and how they should be done. Signifiers must be perceivable, e