Affordances
James Gibson introduced affordances in The Ecological Approach to Visual Perception (1979). An affordance is what an environment offers an animal — a surface affords walking, a handle affords grasping, a cliff affords falling. The affordance exists in the relationship between the animal and its environment, not in the object alone.
Don Norman brought the concept to design in The Design of Everyday Things (1988). A door handle affords pulling; a push plate affords pushing. When the affordance matches the intended action, no instruction is needed. When it doesn’t, people push doors that need pulling.
Norman later clarified: what designers often mean is signifiers — the perceivable cues that communicate affordances. The handle is the affordance. The shape and position that suggest “pull here” is the signifier. A flat plate signifies pushing even though the door physically affords both pushing and pulling.
The distinction matters. A glass door affords walking through (by breaking) but doesn’t signify it. Digital buttons afford clicking but signify nothing without visual design. Physical objects have natural affordances. Digital interfaces have only what designers create.
The best designs align affordance and signifier so completely that users don’t notice either. The action feels inevitable. Doors that need “Push” signs have already failed. The sign is a patch on bad design.
Once you see affordances, you can’t unsee them. Every object becomes a conversation between maker and user. The world divides into things that communicate clearly and things that require instruction.
Norman’s insight: when people struggle with objects, it’s rarely stupidity. It’s design that hides or contradicts the object’s true affordances. Blame the design, not the user.
Go Deeper
Books
- The Design of Everyday Things by Donald Norman — The design classic that brought affordances to general attention. Essential reading.
- The Ecological Approach to Visual Perception by James Gibson — The 1979 original. Academic but foundational for understanding perception as action-oriented.
Essays
- “Affordances and Design” by Donald Norman — Shorter piece clarifying the distinction between affordances and signifiers that he later added.
Related: [[desire-paths]], [[legibility]], [[constraints]]