Norman: The Design of Everyday Things
by Carson Reynolds
Norman begins with some anecdotes about the commonality of frustration with poor designs. He cleverly shows that education, stupid users, etc are not to blame, but instead the difficulty of arriving at a usable design. He discusses the affordances of an interface, the actions that an interface suggests. He introduces the notion of a user’s conceptual model, and briefly discusses mismatches. Lastly, he presents visibility, mapping, and feedback as heuristic for good designs.
“The Psychology of Everyday Actions” details two key concepts: action cycles and “gulfs”.
- Forming the goal
- Forming the intention
- Specifying the action
- Executing the action
- Perceiving the state of the world
- Interpreting the state of the world
- Evaluating the outcome
Gulf of execution (“mismatch between the user’s intention and the allowable actions”) Gulf of evaluation (“mismatch between the system’s representation and the user’s expectations”)
In the next chapter, Norman makes a distinction between knowledge in the head versus knowledge in the world. He then lists attributes of each type of knowledge. Knowledge in the world is retrievable, inefficiently accessed, and highly usable. Knowledge in the head is not readily retrievable (can be ephemeral), once learned is efficiently accessed, but requires experience to use.
“Knowing What to Do” discusses affordances and constraints. Affordances suggest which actions are possible. Constraints, physical, semantic, cultural, or logical, limit the range of actions. He provides examples from the design of doors and lightswitches to illustrate different types of constraints and the frustrations arising from their misuses.
“To Err is Human” begins by taxonimizing errors (“slips”) into capture, description, data-driven, associative activation, loss-of-activation, and mode errors. Norman beseeches readers to design for error: to minimize error states and allow for undo. Forcing functions (physical constraints that allow only proper execution of a sequence of steps) are also briefly discussed.
“The Design Challenge” discusses many of the pitfalls designers encountered. Using the typewriter as a case study, Norman explores the topic. Showing a bias towards utility over visual design Norman cites “Putting Aesthetics first” as one common failing. He also fault designers for designing for themselves, or their clients instead of actual users. After looking at a case study on the design of faucets, Norman moves on to discuss feature creep. The last bit of the chapter is most relevant to problems of adaptation. Here Norman discusses “the foibles of computer systems.” Norman berates poor designs and presents his vision of the ideal interaction as the one in which the computer is explorable. In the future, Norman sees the computer as invisible and intelligent.
The book ends with a call for User Centered Design. Norman wants the design to be automated, however consistent, and with the locus of control in the user’s hands. Norman suggests the complexity of tasks should be minimized. Minimization of complexity might be an interesting heuristic for automatic task construction.