What is Signifier?
A signifier is a perceptible indicator that communicates how something should be used. While affordances are properties that enable interaction, signifiers are the cues that tell users where and how to interact.
How it works
Don Norman introduced the distinction between affordances and signifiers in his 2013 revision of ‘The Design of Everyday Things.’ A flat glass door affords both pushing and pulling, but a ‘Push’ sign (signifier) communicates which action to take. In digital design, signifiers include button borders and shadows (indicating clickability), placeholder text in form fields (indicating what to type), hamburger icons (indicating a hidden menu), and scroll indicators (indicating more content below). Signifiers are particularly important in flat design, where the removal of shadows, gradients, and borders has eliminated many traditional clickability cues.
Applied example
A website redesign adopts flat design, removing button borders and shadows. Click analytics show a 25% drop in CTA engagement because users no longer recognize certain elements as clickable. Adding subtle borders back as signifiers (while maintaining the flat aesthetic) restores engagement.
Why it matters
Signifiers are the communication layer that makes affordances discoverable, solving the practical problem of how users know what they can do and where they should do it.
