Signifier
A perceivable cue that tells people what action is possible and where to take it, the visible half of an affordance and the fix for doors that make everyone push the wrong way.
A signifier is any perceivable cue that tells people what they can do with something and how. A handle on a door, an underline on a link, a raised button shadow, and a blinking text cursor are all signifiers. They answer two questions: what can I do here, and where?
Don Norman introduced the term in a 2008 essay, and made it central to the 2013 revision of The Design of Everyday Things, to fix a confusion his earlier book had caused. Designers had taken up the word Affordance to mean "a visual hint," when an affordance is really the relationship between an object and an actor: a door affords pushing whether or not anything shows it. The signifier is the part people can perceive. An affordance can exist with no signifier, which makes it undiscoverable, and a signifier can promise an affordance that isn't there, which is worse.
The classic failure is the Norman door: a door whose design says pull when it needs a push. A vertical bar handle invites grabbing and pulling, so people pull. A flat plate offers nothing to grab, so people push. When a door needs a sign saying PUSH, the design has failed and a label is patching it.
Screens have the same problem in a harder form, because nothing on a screen is physically graspable. Every interactive cue is a convention people had to learn:
- Links are signaled by color and underline. Removing the underline for style weakens the cue, and relying on color alone fails people with color vision deficiency.
- Buttons were once heavily shaded, a legacy of Skeuomorphism. Flat design stripped those cues, and studies found people spent longer hunting for what was clickable.
- Gestures such as swiping, long-pressing, and pinching have almost no signifiers at all. They are invisible until someone tells you, so apps teach them with overlays.
- Cursors and hover states signal interactivity on desktop but don't exist on touch screens, so a Tooltip or hover reveal can't be the only cue.
- Keyboard focus rings are signifiers for people using Keyboard Navigation. Hiding them for appearance removes the only sign of where input will go.
Good signifiers draw on Gestalt Principles and Visual Hierarchy so the interactive parts read as interactive at a glance, and they match the mental model people bring from other products. Placement is a signifier too: a control near the thing it affects is easier to find than one in a distant toolbar.
Discoverability is the outcome good signifiers produce, the property of people finding what a system can do without instruction. It is one of the first things heuristic evaluation checks and a common finding in Usability Testing, where people repeatedly miss a feature that the team considered obvious.
See also2
Focus Indicator
The visible outline or highlight showing which element on a screen will receive keyboard input, essential for anyone who doesn't use a mouse, and for years routinely removed by designers who found it unattractive.
Design & Interface12 connections
Context Menu
A menu of actions for the thing under the pointer, opened by right-click or long press, which saves travel and narrows choices but is invisible until summoned, so it should never be the only route to an action.
Design & Interface12 connections
Linked from12
- AccordionDesign & Interface
A stack of headings that each expand to reveal a section of content, saving space on long pages and small screens at the cost of hiding what readers might have needed to see.
- AffordanceDesign & Interface
A property an object's design communicates about how it can be used, before any instruction is read.
- Bottom SheetDesign & Interface
A panel that slides up from the bottom of a phone screen to show extra content or choices, often draggable between heights, placed where thumbs can reach it on large phones.
- Command-Line InterfaceSystems & Tooling
Operating a computer by typing commands and reading text replies, the interface inherited from teletypes that remains the fastest, most scriptable, and least discoverable way to control software.
- Context MenuDesign & Interface
A menu of actions for the thing under the pointer, opened by right-click or long press, which saves travel and narrows choices but is invisible until summoned, so it should never be the only route to an action.
- Direct ManipulationDesign & Interface
Ben Shneiderman's 1983 name for interfaces where people act on visible objects with immediate, reversible feedback, such as dragging a file or resizing a shape, instead of typing commands that describe the change.
- Hamburger MenuDesign & Interface
The three-line icon that hides a site's or app's navigation behind a tap, a fix for small screens that saves space at the price of making whatever it hides less likely to be found.
- Heads-Up DisplayPlay & Games
The layer of health bars, ammo counts, maps, and scores drawn over a game's view, borrowed from fighter-jet cockpits, which has to tell players what they need at a glance without burying the world they're looking at.
- IconographyDesign & Interface
The design and use of small symbolic images in interfaces and signage, which are quick to recognize when familiar and surprisingly ambiguous when not.
- TooltipDesign & Interface
A small label that appears when hovering or focusing an element, useful for naming icons and easy to make inaccessible, unreachable on touch, or covered by other layers.
- Touch Target SizeDesign & Interface
How large a tappable element needs to be for fingers to hit it reliably, roughly 44 to 48 points, and why the visible icon can be smaller than the area that responds.
- Visual HierarchyDesign & Interface
Arranging elements so their visual weight matches their importance, telling the eye where to look first, second, and last.