The Design of Everyday Things

One popular prototype technique is called “Wizard of Oz,” after the wizard in L. Frank Baum’s classic book (and the classic movie) The Wonderful Wizard of Oz. The wizard was actually just an ordinary person but, through the use of smoke and mirrors, he managed to appear mysterious and omnipotent. In other words, it was all a fake: the wizard had no

There we have it. Seven stages of action: one for goals, three for execution, and three for evaluation (Figure 2.2). 1. Goal (form the goal) 2. Plan (the action) 3. Specify (an action sequence) 4. Perform (the action sequence) 5. Perceive (the state of the world) 6. Interpret (the perception) 7. Compare (the outcome with the goal) The seven-stage a

FIGURE 1.11. The Designer’s Model, the User’s Model, and the System Image. The designer’s conceptual model is the designer’s conception of the look, feel, and operation of a product. The system image is what can be derived from the physical structure that has been built (including documentation). The user’s mental model is developed through interac

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