Most accidents are attributed to human error, but in almost all cases human error was the direct result of poor design
When you have trouble with things — whether it’s figuring out whether to push or pull a door — it’s not your fault. Don’t blame yourself: blame the designer. When we see an object we’ve never used before, how do we know how to use it? The appearance of the device should provide the critical clues required for its proper operation — knowledge has to be both in the head and in the world.
Conceptual Model. The human mind is a wonderful organ of understanding. A good conceptual model can make the difference between successful and erroneous operation of many devices in our life. Design is an act of communication between the designer and the user, except that all the communication has to come about the the appearance of the device itself.