Affordance

In psychology, affordance is what the environment offers the individual. In design, affordance has a narrower meaning, it refers to possible actions that an actor can readily perceive. American psychologist James J. Gibson coined the term in his 1966 book, The Senses Considered as Perceptual Systems, and it occurs in many of his earlier essays. His best-known definition is from his 1979 book, The Ecological Approach to Visual Perception:The affordances of the environment are what it offers the animal, what it provides or furnishes, either for good or ill. ... It implies the complementarity of the animal and the environment. The word is used in a variety of fields: perceptual psychology, cognitive psychology, environmental psychology, criminology, industrial design, human–computer interaction (HCI), interaction design, user-centered design, communication studies, instructional design, science, technology and society (STS), sports science and artificial intelligence. Gibson developed the concept of affordance over many years, culminating in his final book, The Ecological Approach to Visual Perception in 1979. He defined an affordance as what the environment provides or furnishes the animal. Notably, Gibson compares an affordance with an ecological niche emphasizing the way niches characterize how an animal lives in its environment. The key to understanding affordance is that it is relational and characterizes the suitability of the environment to the observer, and so, depends on their current intentions and their capabilities. For instance, a set of steps which rises high does not afford climbing to the crawling infant, yet might provide rest to a tired adult or the opportunity to move to another floor for an adult who wished to reach an alternative destination. This notion of intention/needs is critical to an understanding of affordance, as it explains how the same aspect of the environment can provide different affordances to different people, and even to the same individual at another point in time.