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XXIII.6 November-December 2016
Page: 7
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back to top  Affordances: Bringing Them Out of the Woods

By Leonardo Burlamaqui and Andy Dong
July–August 2016
DOI: 10.1145/2934292

I find it amusing—but also distressing—to read the imaginative things that people claim I have said, thought, or believed.

So, authors Leonardo Burlamaqui and Andy Dong as well as the editors and reviewers of Interactions, how could you get away with saying (or allowing to be said) “Norman completely recanted his position on affordances, proclaiming affordances do not exist; only signifiers exist.”?

When I complained, the Interactions editors told me that they saw nothing wrong with that statement. They said “the authors and forum editors stand by their point in their argument and statement that you rethought the concept of affordances in light of signifiers.” But that is not what the article said: It said I “completely recanted” my position and that I proclaimed that “affordances do not exist.” What? Rethinking is NOT the same as completely recanting. Adding the concept of signifiers is not the same as saying that affordances do not exist. Am I annoyed? Yes.

Let me try, once again, to explain my position on affordances and on signifiers.

What I did was to distinguish between two components of affordances: the physical part (the interactions something affords to an organism) and the signaling part (the signifier), the perceptible part that signifies the action that the designer wishes to support. I’ve made this distinction in numerous writings: in this magazine and others, as well as in the 2013 revision of the book Design of Everyday Things.

The role played by both affordances and signifiers are of great importance to design. And yes, I believe that for many situations, signifiers are more important than physical affordances. In screen design, for example, affordances play a minor role: It is the signifiers that are critical. And even in such physical devices as doors and light switches, the perceptible parts of the affordances are what is critical: The part that is perceived is the signifier.

Note that the article by Burlamaqui and Dong is excellent. It clearly states the issues and the role for affordances as well as the difficulties of inferring the actions from the affordances (which are not always perceived or even perceivable). I would phrase some of their points differently and reformulate some of their principles, but on the whole, we are in agreement. So why did they have to say that I had claimed that affordances didn’t exist? The statement is false: It gives the design community the wrong idea.

Affordances exist and are important. But affordances are not enough. There must be some way of conveying their existence, of signifying the actions that are possible: This is the role played by perceivable signals—by signifiers.

Don Norman

back to top  Authors Respond:

We would like to thank Donald Norman for his clarification. We believe we were not alone in our interpretation of Norman’s point of view on affordances and, therefore, the whole design community benefits from this clarification.

Regarding Norman’s position on affordances and on signifiers, we are in alignment in important ways. Norman defines signifiers as “the perceptible part that signifies the action.” In our article, we recommended framing as a strategy to highlight the properties of the object conveying information about the intended affordance.

There are a couple of points that keep us puzzled though.

Norman distinguishes two components of affordances, the perceptible part, which are the signifiers, and the physical part, the interactions something affords to an organism. The boundary between the perceptible and physical parts of affordances is vague though. For example, are the shape and texture of a handle the physical parts of its affordance or its signifiers or both?

From a design practice perspective, we believe this vagueness can lead to ambiguous design advice. If we were to advise a designer to make a door handle look more prominent in order to facilitate correct interaction, should we advise the designer to change the physical shape of a handle or add a signifier of the potential interaction? For screen elements, should we advise skeuomorphism or contextual cues, which we named as the strategy of classification? We worry that advising signifiers could result in fewer elegant designs that users readily understand without the use of labels to signify interactions. As we wrote in our article, designers must get the intended affordances right in the first place; else, we end up with a clutter of labels on everyday objects to instruct us on their use.

The aforementioned questions represent a glimpse of the challenges to which we have been exposed in teaching and explaining the concept of affordances to students and practitioners. It is clear that this very central principle of design is something we ought to continue to discuss and clarify. We do hope that our response motivates designers to participate in this debate, so we can apply the concept of affordance in a more effective way—and passengers on airplanes can finally figure out how to open a bathroom door without a sign saying “PUSH.”

Leonardo Burlamaqui and Andy Dong

back to top  Correction

A production glitch in the September-October 2016 issue of Interactions caused the erroneous reflow of some text in the article “Fitter, Happier, More Productive: What to Ask of a Data-Drven Life,” by Chris Elsden, Mark Selby, Abigail Durrant, and David Kirk. The Interactions staff deeply regrets this error. All digital versions of this article have been corrected (DOI: 10.1145/2975388).

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