Why are Mental Models Important to Usability?

“Usability is strongly tied to the extent to which a user’s mental model matches and predicts the action of a system. Ideally, an interface design is consistent with people’s natural mental models about computers, the environment, and everyday objects. For example, it makes sense to design a calculator program that has similar functionality and appearance to the physical hand-held calculators that everyone is familiar with”.

Via Mental Models and Usability. Mary Jo Davidson, Laura Dove, Julie Weltz