Principle of Least Astonishment
The Principle of Least Astonishment (POLA/PLA) applies to user interface design, software design, and ergonomics. It is also known as the rule or law of least astonishment, or the rule or principle of least surprise (POLS).
The POLA states that, when two elements of an interface conflict, or are ambiguous, the behaviour should be that which will least surprise the user; in particular a programmer should try to think of the behavior that will least surprise someone who uses the program, rather than that behavior that is natural from knowing the inner workings of the program.
This practice also involves the application of sensible defaults.
For more information on how to integrate this law into interface design and software feel free to contact the Theme Zoom Natural Language Processing Team and Vertical Online Market Analytis Software Team: