Affordances

I was in a café where they hand out those buzzing things that tell you when your order is ready, so you can come to the counter and collect it. All they do is buzz and flash little red LED lights to attract your attention, then keep buzzing till you hand them back in exchange for your meal.

A young man was chatting with his friend when the thing buzzed. Startled, he jumped up, at the same time seizing the buzzer, staring at it intently and tapping its insensible plastic face, as though half his brain knew it was time to fetch the food and the other half thought an acknowledgement would materialise it in front of him. Or at any rate, knew how to react to a rectangular hand-sized buzzing thing that wanted its attention.

Both of them fell about laughing and he entered into the joke by waving it about and lifting it to his ear.

I regularly try to wave my Oyster* card at my front door; at least half the doors and gates in my life open when you wave things at them, and it is an effort to remember that this one requires a physical key.

In my place of work there are so many doors that behave in totally different ways. There are a few normal doors that you push or pull. There are doors that you wave a card at, and they slide open. There are doors that you wave a card at, and they open on a hinge, but very, very cautiously, so that thin people go in first. There is a door consisting of two glass blades that meet in the middle, which requires you to wave a card at it, and is so very like the barriers on the Tube that I always reach for my Oyster card; except that the LED "go" or "stop" display means something totally different and contradictory.

There is a worrying kind of glass revolving door, such that you have to wave your card at it to unlock it, then step into a little 45-degree pocket, whereupon it starts revolving, and you shuffle very slowly around to be spat out at the other side. On no account must you push anything, since if you do it will panic, freeze, and trap you like a fish in a tank, so the security guard will have to come and press buttons to let you out.

There are two variations of a subtly different kind of revolving door that does exactly the same thing, except that it starts revolving when you get close enough (there's no indication of where you have to stand, or what is going to happen). One of those has a green button nearby that looks as though it might be a "request to exit" button; if you press it, the door gets stroppy and freezes, much to the annoyance of the people outside trying to get in. There are also some old-fashioned revolving doors that you just push; so that you stand there like a lemon trying to guess what you're meant to do.

And almost all these doors behave differently depending on whether you are going out or coming in. There are many doors where you have to do something to unlock them, and then do something else to open them, such as push or pull, with all the possible confusion that entails - but not too quickly, and not too slowly. Different doors I meet in the course of my day's work require staff cards issued by two different companies, both of which I am supposed to wear in a visible way (unless I am crossing the road between buildings, in which case I am advised to conceal them). But you cannot keep these two cards in the same container, because then they stop working. Neither can you keep any of them with your Oyster card, or that will stop working, too.

I am always standing in front of doors and hunting around for the "Open, Sesame" buttons that mean "unlock, I want to get out". They all look different from each other, and they're never in the same place twice.

It's a DOOR. You're not supposed to have to read the instructions.

The world is so confusing. No wonder it makes us nervous and inexplicably vexed.

* For non-Londoners, the Oyster card is the electronic ticket card that pays for bus journeys and opens barriers on the Tube.