What is affordance?
Affordance is the set of actions an environment offers to a particular actor. Whether a function exists and whether the actor can find it in the interface are two different questions; the second also needs signifiers, which are perceivable and understandable cues for how to operate.
Signifier
A signifier is a perceivable cue used to judge a purpose, an action or a state. For example, a button label suggests what can be done, and a booking number points to a record that has been created. A cue being present does not mean the function is actually available.
Why the same interface looks different to people and AI
A person may recognize a button by its color, shape and position, while an AI agent may receive the DOM, an accessibility tree or a screenshot. The same entry point can be clear under one way of observing it and lack identifiable information under another. This is how the affordance view is applied to the analysis of AX.
For example, a booking button that can be submitted but has no identifiable name still exists as a function, yet its operating cues may be insufficient. Conversely, an element that looks clickable on screen but is not accepted by the back end cannot be judged usable from its appearance alone.
Check affordance and signifiers separately
When checking affordance, ask: what can this actor actually do in the current environment? When checking signifiers, ask: what cues does the interface give so that the actor knows where to act and what state things are in?
After an action succeeds, the agent still needs a verifiable result. A "Thank you" message on screen and a booking record that can be queried in the back end support different conclusions.
Sources and scope
Sources as checked for the source-language entry on 2026-11-06; this English edition adds no new claims and does not represent a new check of the cited pages.