‘The Design of Everyday Things‘ is a 1988 book by cognitive scientist and usability engineer Donald Norman on design’s role in enabling communication been objects and their users, and how to optimize that conduit to make the experience more effective. One of the main premises of the book is that although people are often keen to blame themselves when objects appear to malfunction, it is not the fault of the user but rather the lack of intuitive guidance that should be present in the design. In the book, Norman introduced the term ‘affordance’ as it applied to design, defining it as things that afford the opportunity for an organism to perform an action.
For example, a knob affords twisting, and perhaps pushing, while a cord affords pulling. 20th century American psychologist James J. Gibson originally coined the term ‘affordance’ to describe changes made to one’s environment to make them more usable, such as carving stairs into a steep hill. Norman also popularized the term ‘user-centered design’ to describe design based on the needs of the user, leaving aside what he deemed secondary issues like aesthetics. User-centered design involves simplifying the structure of tasks, making things visible, getting the mapping right, exploiting the powers of constraint, designing for error, and explaining affordances.
The Daily Omnivore 