Definitions to remember Gulf of Execution Difficulty or ease in mapping from conceptual goals to physical control changes necessary to achieve goals. How well changes to physical map to goal. Cues Icons that suggest what they control. The first GUI system was invented by Xerox in the early 70's. Learning is guided by prior knowlege.
Users make mistakes.
200ms - 30sec. People can't remember very much for very long. Here is a link to another bad designs . This is considered a bad design because they did not follow some or all of the guidelines above. We quickly parked the car in the college parking lot, and then saw a sign saying we had to buy a parking permit.