Affordance is a relation between object properties and user capabilities

What it is

An affordance is an action relationship supported when environmental or object properties meet a particular user's capability. A handle affords pulling for someone able to grasp it; the same object need not afford the same action to a child, gloved user, or remote operator. It is neither a visual style that “looks like a button” nor whether the person notices the action.

Why it happens

Action possibility arises jointly from shape, material, state, rules, and a user's body, skill, and tools. An affordance can exist unnoticed, while a cue can falsely suggest an action that system rules do not permit. In digital interfaces, clicking, dragging, and input also depend on platform events, permission, and assistive technology, not on pixels alone.

Studying it

Define the target action and intended capability, then observe whether it can actually be completed under real constraints rather than only asking for impressions. Task observation, accessibility assessment, error analysis, and contextual interviews can examine how properties, permission, input, and bodily conditions jointly constrain action. Separate actual possibility from perceived possibility.

Where it stops holding

Affordance is relational: no object is simply “inherently affordant” apart from a user. It differs across mouse, touch, keyboard, voice, and assistive input. Nor should every potential action be exposed; safety, permissions, and workflow can intentionally restrict action.

Applying it

• Define required actions for specific devices and capabilities, then verify that the system permits them, hit areas are reachable, and permissions align.
• Provide at least one viable route to critical action that does not rely on a single limb or input method, and explain constraints on failure.
• Record “noticed but could not do” separately from “could do but did not notice”; they require different repair.

Related

• Same group: B2.01.2 Existence of an affordance differs from noticing it · B2.01.3 Anti-affordances also need expression · B2.01.4 Screen affordances are learned rather than physical
• Nearby: B2.02 Perceived affordance · B2.03 Signifiers
• Search terms: affordance · action possibility · Gibsonian affordance