Missing and declining affordances: are these appropriate concepts?

The concept of affordance has been brought to HCI by Don Norman, who has recently protested against its misuse by designers. They say they will put affordances in the interface, or afford this or that to the users, but Norman points out that affordances only exist inasmuch as they are perceived by users. Therefore, it doesn’t make sense to use the term as designers do. This paper takes the designers’ phrases as a spontaneous expression of design intent and explores the correspondences between these and two of the phenomena captured by communicability evaluation: missing and declining affordances. It highlights some useful distinctions between levels of affordances, and hints at possible links between communicative and cognitive perspectives. It suggests that framing affordances within a broader communicative dimension, and taking advantage of the rhetoric that people use to describe what they are doing, can bring interesting insights to design.