Users can only use affordances they perceive
Aliases: perceived affordance · perceived action possibility · discoverability
What it is
An interface may technically support an action, but people can use it only when they notice it, understand when it is available, and consider trying it. A perceived affordance is an action possibility inferred from present cues. It differs both from the input the system actually accepts and from whether the person ultimately succeeds.
Why it happens
People predict operability from appearance, position, wording, prior experience, and their current goal. Clickable text, a draggable handle, or an expandable area can remain outside attention when its cues are weak. Conversely, a conspicuous treatment can imply an action the system does not support. Perception precedes action; feedback then reinforces or corrects the prediction.
Studying it
Ask participants to accomplish a concrete goal without instructions. Observe what they notice, try first, overlook, and how they explain the current state. Eye tracking, think-aloud, and post-task interviews can distinguish not seeing an element from seeing but not understanding it, or understanding but not trusting it. Compare experience groups so expert familiarity is not mistaken for clear cues.
Where it stops holding
Perceivability does not require every function to remain exposed: infrequent or advanced capability may appear progressively in an appropriate context. Too many interaction cues compete for attention and obscure the primary task. Perceived affordance also varies with language, culture, input method, and assistive technology, so visual review alone cannot establish it.
Applying it
- Give actions needed for the current primary task labels, forms, or placement cues proportional to their importance.
- Pair operable objects with consistent state change and immediate feedback so people can test their action predictions.
- Test discovery rates in first use, task switching, and different input modes; treat an undiscovered critical capability as a design problem.