Sensory Characteristics

WCAG 2.1 Success Criterion 1.3.3 (Level A), which requires that instructions for understanding and operating content not rely solely on sensory characteristics such as shape, colour, size, visual location, orientation, or sound. Examples that violate 1.3.3 include referring to the "round button" or "the form on the right", or conveying errors only by turning a field red. Mobile-accessibility research frequently cites this criterion when faulting apps that use colour or animation as the sole channel for feedback to blind screen reader users.