UX glossary
Affordance
An affordance describes what action an object makes possible and whether people can recognize it: a button invites you to press it, a handle invites you to pull.
Picture a glass door with a big handle. You pull it, but the door only opens inward. The handle told you “pull me” when pushing would have been right. Doors like this are so common that they have their own nickname: Norman doors, named after design researcher Don Norman.
The same thing happens on screens when text looks like a button but does nothing, or when a button is so flat that nobody notices it.
Explained simply
An affordance describes what actions an object makes possible. A chair affords sitting, a button affords pressing, a slider affords sliding. What matters for design is whether people can actually recognize that possibility.
The term comes from American psychologist James J. Gibson. He introduced it in 1966 and explained it in detail in his 1979 book on visual perception. For Gibson, an affordance was a relationship between an environment and a living being: a high step is a place to sit for an adult but an obstacle for a toddler.
Don Norman brought the term into design in 1988 with the book now known as “The Design of Everyday Things.” He mainly meant the perceived possibilities for action. You can find more about the book in the resource The Design of Everyday Things.
Affordances and signifiers
Because designers often used the term loosely, Norman later introduced a second one: the signifier, a perceivable cue that shows where and how you can act. The affordance is the possibility, the signifier is the hint. On a touchscreen, you could theoretically tap anywhere. Only shape, color, shadow, or labels tell you where tapping actually does something.
Problems come from two directions. A hidden affordance exists but can’t be seen, like a swipe menu with no visual hint. A false affordance promises an action that doesn’t exist, like a heading styled as a button. A 2017 eyetracking study by the Nielsen Norman Group found that participants needed about 22 percent more time on average to find clickable elements on pages with weak clickability cues.
An example
Here’s an example. A banking app shows the “Send transfer” button as gray text with no border, the same size as the body copy. Many people tap next to it or scroll up and down looking for it.
After the redesign, the button is a colored shape with rounded corners and strong contrast. Plain text, on the other hand, is never highlighted in color anymore. Without a single line of explanation, it’s now clear what’s tappable and what isn’t.
In practice
- Make clickable things visible. Buttons need a recognizable shape, and links need a distinct color or underline that sets them apart from body text.
- Don’t make false promises. Don’t style non-clickable elements like buttons or links, or people will tap and get nothing.
- Stick to conventions. Familiar patterns are strong signifiers. For more typical pitfalls, read Common Usability Mistakes and How to Avoid Them.
Related terms
Mental Model, Gestalt Principles, Microcopy, Usability Testing