Models and Theories in Human-Computer Interaction/Relational Affordance

In 1988, Donald Norman published a book titled "The Design of Everyday Things". This book has several interesting topics, including the definition of the concept of affordance. Norman wrote that “The term affordance refers to the relationship between a physical object and a person (or for that matter, any interacting agent, whether animal or human, or even machines and robots). An affordance is a relationship between the properties of an object and the capabilities of the agent that determine just how the object could possibly be used.” (Norman, 1988)

To go a step further, it is further clarified that an affordance is relational versus subjective. He later addresses the issue of the affordances of glass. An animal (or humans, in some cases) may subjectively think that glass is clear, and therefore matter can pass through it. This can be seen with small children and infants as they are amazed when they are introduced to glass for the first time. However, on a relational basis matter cannot pass through glass but sight can, which give us the affordance (or in this example, the blockage provides for an anti-affordance) that “glass affords seeing though and support, but not the passage of air or most physical objects)” (Norman, 1988)

Norman also makes it very clear that affordances and anti-affordances need to have the capacity of being perceived- if the capability of perception is not present, it cannot be an affordance.

References Norman, D. (1988). The Design of Everyday Things. New York: Basic Books.