Intro to the theory of stuff

April 18, 2011 11:41:44 PM CDT

In The Psychology of Everyday Things, Don Norman uses the term 'affordances' to mean 'things you can do with an object'. It's a useful idea, and the term is less pretentious than something like 'latent functionality'.

Strictly speaking, affordances include any potential use for an object. A chair and a basketball both have the affordances of 'sitting' and 'throwing' even though most people will probably sit in the chair and throw the ball. Norman uses the term to mean the ways most people think of using an object (thus the preference for sitting in the chair), though he later admitted that he should have used a qualifer like 'perceived affordances'. I happen to like the term 'primary affordances'.

Most people think about objects in terms of primary affordances. [1][2] A chair is for sitting; a ball is for throwing; a door is a way of walking through a wall that optionally keeps out the draft. It's a handy way to keep track of the countless objects the world throws at us, and saves us from having to sift through a bazillion previously-seen-object templates for the meaning of 'spoon'.

It's nearly useless for making stuff, though.

All you can ever make is a single thing. Even if you have an assembly line that cranks out a million units a day, you have to make each item one at a time. Each item has specific dimensions, and is made of distinct material. Making stuff forces you to deal with specifics, so it forces you to think about objects in terms of materials and dimensions.

The process of choosing materials and dimensions to provide a given set of primary affordances is called 'design'. Norman spends an entire book talking about the issues involved in design, and does it better than I possibly can. Read it and learn how to use, "probably won an award," as an insult.

The process of taking a hunk of material and a set of dimensions and producing an object is called 'fabrication'. That's the subject I find most interesting right now. It turns out there's a whole body of theory and philosophy supporting the idea of fabrication, much of which is lost in the final product.

Illustrative story: The columns at the Acropolis don't have straight sides. They bulge slightly, and the bulge makes them look better. Thing is, the radius of curvature is huge.. something like a mile. For centuries, people have wondered how a huge crew of masons managed to cut such large curves so precisely.

An archeologist studying an unfinished temple from the same era found the answer: there was an arc carved into the rough surface of the wall, a vertical line half a column's width away, and a series of horizontal lines a few inches apart cutting them both. The masons could take their measurements from that diagram, stretch the distance between marks to feet rather than inches, and get exactly the curve they needed.

The sneaky part is that once the columns were done, the diagram would be carved away as the masons smoothed the wall to its finished surface.

That's what I mean by information being lost in the final product.. just knowing what something is doesn't mean you know how to make it.

If you know the theory and philosophy of fabrication, you can make amazing things fairly easily. If you don't know them, you can waste huge amounts of time and effort to get results that are mediocre at best.

[1] - There's a whole realm of art, humor, and general ingenuity that revolves around looking past an object's primary affordances and seeing what else it can do. That's pretty much the definition of lateral thinking, in fact.

[2] - If you want to get philosophical about it, most nouns are just labels for collections of contextually related verbs. It's good to remember that when you run into the writer's dictum, "write with your verbs, not with your nouns."

An apple is a thing, but which affordance do I care about? The one that keeps the doctor away? The one for teacher? The one I can taste? The one that symbolizes original sin? The one that allegedly gave Newton the idea for gravity? Figure that out, and you'll be able to write about your apple much more effectively.