Book Review: The Design of Everyday Things

Applying Norman’s Principles of Interaction in the Real World

Norman outlines a set of concepts that can help UX designers create products that communicate their purpose, usefulness, and how to interact with them effectively.

Affordance is the most basic principle that Norman discusses, but people frequently misunderstand it. In short, an affordance is what an object is supposed to do. For example, a door provides a way to close a doorway. It might latch and lock. These are the door’s affordances.

Signifiers communicate an object’s possible affordances and provide hints on how to achieve them. A label on a door that says PUSH helps users to realize that they should push the door.

While affordances and signifiers are just two of Norman’s design principles, they can illustrate the flexibility of a user experience. We can trace much of the confusion that users encounter when using a tool back to the omission of one or more Norman design principles or conflicts between them. The obvious example that people frequently use is the concept of the Norman Door—a door or a set of doors whose affordance indicates they swing in one direction, while the attached handles signify that they swing in the opposite direction. Of course, intentionally attaching signifiers to the doors in a vain attempt to reduce people’s misunderstandings of their affordance can exacerbate users’ confusion, as the photo in Figure 1 shows.

Obviously, we can apply these principles to the usability of Web sites. For example, if a string of text has the affordance of being a link, but lacks some text decoration that would provide a signifier that the text is indeed a link, its usability would be challenging.

Norman provides detailed explanations of all of his principles, which UX designers can apply to influence users’ experience in positive ways. Plus, he provides assessments of the cognitive responses that users experience when interacting with an object, as well as when evaluating their expectations of an interaction’s result and the actual result. Naturally, when the observed result of an interaction doesn’t match the user’s expectation, this can cause confusion and make the user reject the tool.

Conclusion

The Design of Everyday Things is required reading for anyone who is interested in the user experience. I personally like to reread it every year or two.

Norman is aware of the durability of his work and the applicability of his principles to multiple disciplines. As he notes in the final chapter of his book:

“It should be no surprise that I believe they will always be just as relevant as they were twenty-five years ago, just as relevant as they are today. Why? The reason is simple. The design of technology to fit human needs and capabilities is determined by the psychology of people. Yes, technologies change, but people stay the same.”

Pittsburgh Steelers Coach Chuck Noll said, “If you want to win, do the ordinary things better than anyone else, day in and day out.” While the UX community discusses and debates trends such as augmented reality (AR), artificial intelligence (AI), skeuomorphism, neumorphism, and flat user interfaces while confronting tool-selection and ethical dilemmas, it is important to recognize the value of the fundamental principles to our profession. I value a UX professional’s ability to recognize the value of Norman’s principles of interaction over their choice of Sketch or Zeppelin or whether someone has designed one or a hundred mobile apps for a given industry. If you know the basics of design better than anyone else, you can apply them flawlessly anywhere.