Lou Fuiano
ITI Spring 2006
Duff

Affordances: Clarifying and Evolving a Concept
Graphics Interface 2000, Montreal
Joanna McGrenere, Wayne Ho

In Norman we Trust

This essay is in response to an article that was written in 2000. Several contributors at the conference were working to understand the contrast between how James J. Gibson and Donald Norman were defining "affordance".

Affordance: How an object should be used. -or: Is for.

I thought it was very revealing that most of the contributors at the conference were eager to cite Gibson, but ultimately were recounting the points made by Norman. That seems reasonable. The theories being discussed have many new applications. At times, they sounded over analytical and abstract, until specific examples are laid out. The overlap between the two is almost inevitable.

While Gibson has strong initial points, they are somewhat un-evolved. Understanding the "surface Information" as affordances, and how we navigate and use these for better or for worse. This seems primitive to me. Do we not understand the behavior of materials once we become familiar with their basic properties? Gibson's stairway example is useful in understanding his point: The stairway design is binary. Nothing hidden, no experience required; just climb. Gibson does not detail a degree of difficulty in using the stairs. However, it seems a bit early in the discussion to be detailing difficulty. My assumption was that he wants to state a general understanding of affordances. Also, he disregards the experience of the user, or "Actor". "Learning can be seen as a process of discriminating patterns in the world rather than one supplementing sensory information with past experience". What you see will affect your behavior regardless of what you know? This presents the main conflict between the two arguments.

Gibson does however elude to nested affordances. This is discussed further in the subsequent articles by other writers and also points out a more complex role of affordances.

Norman gives the concept of affordance a more defined form. His theory helps to connect the design of things to human behavior. A particularly helpful point is: Perceived Affordance and Actual Affordance. An object visually implies it's use, and then delivers. A doorknob or handle gives the visual clues, and, when engaged, opens the door. This one point makes perceived and actual affordances inseparable and requisite for effective design.

Norman also calls on past knowledge of the user. "I believe that affordances result from the mental interpretation of things, based on our past knowledge and experience applied to our perception of the things about us". He points out that affordances "provide strong clues to the operation of things". This brings the discussion together.

Two contributors that caught my attention were Warren and Gaver. Warren, an ecological psychologist, states that design should be fitted to the individual and work with the target user in mind. This would consider difficulty and proportion the usability of something more specifically. A paper by Smets, Overbeeke & Gaver discusses design that can utilize non-visual clues like sound, smell, taste and texture. This clearly falls into the category of multimedia, as this form is becoming more and more commonplace. Gaver also discusses "design as the information that specifies the affordance". This point begins to take hold for designers. His mention of "sequential affordance" seems most applicable to the software design community where click, drags, scrolls and dynamic lists are commonplace.

Late in the article there is a discussion section where the writers ask "Does it matter?" Norman is quoted: "Sloppy thinking about the concepts and tactics often leads to sloppy design". While it might seem as though he is stating the obvious, that point had particular resonance with me. The language and vocabulary of these theories is of great importance as we evolve as designers and users.

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