01
Align sign and action
Choose Legible invitation. Most actors both perceive and can perform the intended move.
communicoupling
The handle offers
a move.
A flat plate affords pushing; a handle affords pulling; a low ledge affords sitting for one body and blocks another. We do not first perceive neutral geometry and then attach every possible use. Environments arrive already structured by possibilities for action.
James J. Gibson called those relations affordances. An affordance belongs neither to the object alone nor to the actor alone. It exists in their fit. Social environments similarly invite, discourage, and distribute action before anyone issues an explicit command.
cue clarityhow visibly one action is invited
action costeffort separating the intended move from alternatives
user diversityspread of bodies, skills, and prior conventions
intended action
—
actors selecting the designed move
ambiguous choice
—
actors whose best options are nearly tied
excluded actors
—
actors for whom no available action clears its cost
The same environment across differently situated actors
gold: intended action by ability band · red: exclusion; a visible cue is not the same as a usable affordance
Set the conditions
what to try
Distinguish a cue from a possibility.
02
Build a Norman door
Choose Norman door. The mechanism works, but its visible form leaves pushing and pulling too evenly supported.
03
Design for one body
Choose One-size design. The cue remains clear while rising cost and diversity reveal that legibility does not guarantee access.
the mechanism
Action possibilities are relations, not labels.
The model presents several possible actions to actors whose capacities and learned expectations vary. Cue clarity gives the intended action a perceptual advantage. Action cost subtracts from its usability, especially for actors far from the assumed body or skill. Agents select the highest positive utility; a narrow margin counts as ambiguity, while all-negative utility counts as exclusion.
The crucial separation is between an affordance and its information. A handle can afford pulling even when nobody notices; a painted false handle can suggest pulling when the door cannot move that way. Design governs behavior by arranging both possibilities and the cues that disclose them.
the social payoff
Environments coordinate by making action easier to see and take.
Architecture, interfaces, forms, seating plans, permissions, and workflow defaults distribute possibilities unevenly. A reply button, locked gate, prefilled field, or round table changes the action landscape before motives and messages enter.
Affordance analysis therefore complements stigmergy: affordances concern what the environment currently makes possible; stigmergy concerns how action modifies that environment for later action.
the mapping
Mechanism ↔ social life.
| In the model | In the world |
|---|---|
| cue clarity | How strongly form or convention indicates a particular action. |
| action cost | Physical, cognitive, procedural, or social effort required to take it. |
| user diversity | Variation in bodies, skills, histories, permissions, and expectations. |
| ambiguity | Several actions appear similarly plausible. |
| exclusion | The nominal function is not practically available to a situated actor. |
where it tears
Limits.
Affordance is used in several incompatible senses.
Ecological psychology, product design, sociology, and computing often mean different things. The page keeps Gibson's relational core while modeling perceived cues separately.
Ease is not consent.
Making an action effortless can manipulate as well as assist. A bright acceptance button and hidden refusal path are affordance politics.
People improvise.
Actors discover uses no designer represented and collectively teach them to others. The action landscape is open-ended, especially in social settings.