19. Affordance

Affordance by Don Norman

“Affordances define what actions are possible. Signifiers specify how people discover those possibilities: signifiers are signs, perceptible signals of what can be done. Signifiers are of far more importance to designers than are affordances.” [Donald A. Norman, The Design of Everyday Things: Revised and Expanded Edition, 2013, pXIV-XV]

Four Principles of Affordance

There are four principles of affordance that are important to keep in mind as a visual designer.
Follow convention
Support visuals with text
Build on metaphors, use text
Be consistent create a coherent model