p 12
Irving Biederman, a psychologist who studies visual perception, estimates that there are probably "30000 readily discriminable objects for the adult".
p 54
Why the apparent discrepancy between the precision of behaviour and the imprecision of knowledge?
p 57
Declarative and procedural knowledge, knowledge OF and knowledge HOW. Declarative knowledge is easy to write down and to teach. Procedural knowledge is best taught by demonstration and best learned through practice. [It] is largely subconscious.
p 78
If a design depends upon labels, it may be faulty. Labels are important and often necessary, but the appropriate use of natural mappings can minimize the need for them. Wherever labels seem necessary, consider another design.
p 126 Conscious and Subconscious Behavior
Start with the nine numbers 1, 2, 3, 4, 5, 6, 7, 8, and 9. You and your opponent alternate turns, each time taking a number. Each number can be taken only once, so if your opponent has selected a number, you cannot also select it. The first person to have any three numbers that total 15 wins the game.See Tic-tac-toe.
[...]
To see the relationship between the game of 15 and tic-tac-toe, simply arrange the nine digits into the following pattern:8 1 6 3 5 7 4 9 2[...]
The transformations of tic-tac-toe have made a complex task into an everyday one.
p 131 Designing for Error
Change the attitude toward errors. Think of an object's user as attempting to do a task, getting there by imperfect approximations. Don't think of the user as making errors; think of the actions as approximations of what is desired.
p 132 Forcing Functions
Forcing functions are a form of physical constraint: situations in which the actions are constrained so that failure at one stage prevents the next step from happening.
p 140 A Design Philosophy
p 157 Designers are not Typical Users
Innocence lost is not easily regained.