Amar Sagoo

28 April 2006

To afford or not to afford...

I’ve always been a bit of a pedant, and in that spirit, I would like to write about some use of terminology in interaction design that has been bugging me: affordance. If you’re familiar with the field, the lengthy debates around what the word exactly means may be an old hat to you. Here’s some quick background if you aren’t.

Affordance is a term coined by psychologist James J. Gibson in 1977 to denote the actions an object or environment allows a person to perform. For example, some of a stick’s affordances are touching, picking up and poking someone with. The word is simply a derivative of the verb “afford”.

In his popular (and great!) book The Design of Everyday Things (originally published as The Psychology of Everyday Things), Donald Norman reinterpreted the term to mean those actions which a person can readily perceive to be possible, i.e., those the environment suggests or invites you to perform. Norman’s affordances are a thus a special subset of Gibson’s affordances. They also become something that’s desirable in the design of interfaces; if a button doesn’t look like it can be pressed, the user probably won’t press it.

Norman later realised the discrepancy and has been trying to re-educate the world, who love using his earlier interpretation of the term, but to little avail. Most people nowadays still use affordances to refer to those interactions which are apparent.

It is debatable whether this is a problem. Although Gibson’s meaning is the only logical one, people jumped on Norman’s use for a reason: the meaning he introduced is a very useful concept that needed a name. One could argue that a new word should be invented to signify perceived affordances, but that’s not a very realistic undertaking, since even Norman himself has failed to change people’s minds.

What all the discussions about this terminology seem to overlook, however, is that in adopting Norman’s meaning of the noun, people have also re-applied it back to the verb Gibson’s original term was based on. To afford no longer means “to allow”, but “to suggest” or “to advertise”!

What’s wrong with “advertise”?

I get the impression that people of any particular discipline somehow love having terms that only they understand.

1 comment:

David W said...

Nice point, Amar, I hadn't spotted the change in use of the verb.

This sort of thing is everyday in other disciplines like philosophy and sociology, where for most technical terms ("ideology", "realism" spring to mind) you have to (a) point out that you are not using the term in its "everyday" usage and (b) namecheck the originator or the particular version of the concept you want to use.

Though this is tiresome, it does actually work, and in many cases is useful because it forces people to clarify terms rather than using them ambiguously. Also gives us pedants plenty to think about.