Sensory Characteristics ensure that instructions for using or understanding content do not depend solely on visual, auditory, or positional cues. Users must be able to follow instructions based on text, labels, or names, rather than appearance alone.
This criterion applies specifically to instructions, not to visual design in general. Colour, shape, size, or location may be used as supplementary cues, but they must never be the only way a user can identify what to do.
When instructions rely only on shape, colour, size, location, orientation, or sound, many users cannot follow them.
WCAG Success Criterion
This requirement is defined by Success Criterion 1.3.3 Sensory Characteristics (Level A). Instructions for using or understanding content must not depend solely on sensory characteristics such as shape, colour, size, location, orientation, or sound.
Note: Requirements specifically related to colour contrast and colour-only meaning are addressed under Guideline 1.4. This criterion focuses on instructions, not visual styling.
What Proper Sensory-Independent Instructions Look Like
Instructions are accessible when:
- Controls are identified by text, label, name, function, or role
- Sensory cues are optional, not the sole method of identification
- Users can locate and operate controls without seeing, hearing, or interpreting spatial layout
Acceptable Instruction Example
“Select the Submit button below the form.”
A spatial cue is present, but the control is also identified by its label.
Unacceptable Instruction Examples
“Click the round button.”
“Choose the option on the right.”
“Continue when you hear the beep.”
These instructions rely entirely on sensory characteristics and provide no non-sensory identification.
Why This Matters
Some users cannot reliably perceive:
- Shape
- Color
- Size
- Spatial position
- Orientation
- Sound
This includes users who are blind or have low vision, users with cognitive disabilities, and users accessing content through screen readers, audio output, or linearised layouts.
When instructions rely only on sensory cues, users are forced to guess. Providing text-based identification ensures that instructions remain understandable regardless of differences in perception or presentation format.
Examples
Fails
A sports schedule uses colored icons to indicate event locations. Instructions state:
“Events with a blue diamond are on Field A and events with a green circle are on Field B.”
Meaning is conveyed only through colour and shape, so users who cannot perceive those cues cannot follow the instruction.
Passes
A survey uses a green arrow icon in the lower-right corner for navigation, but the icon is labelled “Next.” Instructions state:
“To continue, select the Next button.”
Visual cues remain helpful, but the instruction does not depend on them.
Common Failure Patterns
This criterion commonly fails when instructions say:
- “Click the red button”
- “Use the menu on the left”
- “Select the option above”
- “Listen for the tone and proceed”
In each case, the instruction depends on a sensory characteristic without providing a non-sensory identifier.
Common Practices to Meet This Rule
To meet Success Criterion 1.3.3:
- Refer to controls by their accessible name or visible label
- Ensure instructions make sense without colour, position, shape, or sound
- Use sensory cues only as additional guidance, not as the sole instruction
Labels and accessible names help users identify controls.
Instructions must reference those names, not their appearance.
Who Is Affected
Improper sensory-based instructions affect:
- Blind and low-vision users
- Users with cognitive or learning disabilities
- Users accessing content without visual layout or colour styling
- Users relying on screen readers, audio output, or alternative presentations
Rule Description
Instructions must not rely solely on sensory characteristics for users to understand or operate content. Controls must be identifiable through text or name, without depending only on colour, shape, size, position, orientation, or sound.
The Algorithm
- Review instructions provided to users
- Check whether a control can be identified without sensory information
- If understanding requires knowing colour, shape, position, or sound, and if no other identification is provided, the criterion fails
Wrapping Up
Sensory Characteristics ensure that instructions remain usable even when appearance or sound cannot be perceived. By identifying controls through text or labels rather than sensory cues alone, authors ensure users can understand what to do without guessing.
This criterion does not prohibit visual or auditory cues; it simply requires that they are never the only way instructions are conveyed.
