Design space properties

The characteristics of information within a design space, classified by the type of cognitive processing they require. Direct properties relate to perception and automatic processing — colour, brightness, and pitch are perceived immediately without conscious effort. Indirect properties relate to cognition and controlled processing — reading text, interpreting symbols, or understanding spoken language requires active mental effort. This distinction is significant for accessibility because impairments may affect perception, cognition, or both. A user with colour blindness has a direct property impairment in the visual design space, while a user with a learning disability may have difficulty with indirect properties. Effective accessible design uses redundant encoding — conveying the same information through both direct and indirect properties — so that impairment in one does not prevent understanding.