CONCEPT
Signifiers
The perceivable cues that tell a person what an object affords — separate from the affordance itself, and in the AI era almost entirely absent, misleading, or replaced by accidental signals the system never intended to send.
Where an affordance is what an object permits, a signifier is what the object communicates about that permission. The raised button signifies "press me." The slider's track signifies "drag along this axis." The menu's visible list signifies "choose from these options." Norman's central design thesis was that affordances and signifiers must align: the perceivable cue should accurately represent the actionable possibility. When they misalign — when signifiers exist without underlying affordances, or when affordances lack perceivable signifiers — the result is systematic user failure that designers often misattribute to user error. The AI interface has created an unprecedented signifier crisis: a system of vast capability whose blank-prompt surface signifies nothing, and whose polished outputs signify meanings the system never meant to communicate.
In The You On AI Field Guide
The signifier-affordance distinction, clarified in Norman's 1999 essay and elaborated in the second edition of The Design of Everyday Things, resolved a decade of conceptual confusion in the