Signifier
A signifier is a perceivable mark, sound or cue that tells a person what can be done and where. The term is Don Norman's, from his design framework in The Design of Everyday Things, and it works through shared convention: a mark can only point to an action for people who have learned what it points to.
What it is
Norman's book builds a vocabulary for why some objects are easy to use and others are not. A signifier is one of its parts. It sits beside affordance, mapping, feedback and constraints, and it is the part that communicates.
The book is a framework, so most of it is definition rather than finding. The signifier is Norman's own term, adapted from semiotics, and this page presents it as his account, not as a tested result.
In effect
The Why We Project uses the concept in its article on green color psychology to describe what it calls the permission reading of green. In Norman's account, signifiers and conventions let people act without memorising, conventions are learned, and changing a convention meets resistance. By that account, a green mark on a control can point to go ahead only for people who have learned that reading, and only in the settings where they learned it.
That application is the article's interpretation. The article states that no experiment it reviews tests green as a sign of permission in branding, and it treats the convention account as a framework for how meaning attaches to a mark.
What it does not say
The concept does not say which colour carries which meaning, and it does not claim that any colour is a universal signifier. It does not supply evidence on trust or on consumer choice. It describes how a mark can communicate, and the meaning of a particular mark has to be established by the people who use it.
Sources
- Norman, D. The Design of Everyday Things.