How To Avoid Foolish Consistency
http://www.uiweb.com/issues/issue05.htm

Berkun, Scott
UIWeb
1999

Abstract:

People don't like to learn things. If they take the time to learn something, they expect to be able to apply that knowledge in many places. It follows that good designers conserve the number of things users need to learn to get stuff done. The streets in American cities are good examples of conservation of knowledge. Anywhere in America, yield and stop signs look exactly the same. Traffic lights use red, yellow, and green to mean precisely the same things regardless of the street or city. Mailboxes on street corners use the same colors and icons, so they are clearly identifiable anywhere. It becomes difficult for people when their knowledge of things breaks down. A driver from a country with different street signs who visits America will make mistakes until they learn the new signs. Even subtle variances like the difference in speed of two different yellow traffic lights can cause American drivers to make mistakes.