Monday, 16 September 2013

Affordance: the case of door closing

Last week, I was at (yet another) hotel. In the Ladies' (and presumably also the Gents'), the doors had door-plates on the inside, which facilitated pushing but not pulling. Within HCI, this is often referred to as the object affording a particular action. See, for example, work by Gaver and Hartson. In fact this example goes further than affording: it determines what is physically possible. In the case of doors, the assumption is that on one side you expect to pull and on the other you expect to push.

The problem was that in this case the door hinge was very simple: the door did not automatically close. So the only way to close the cubicle door was to pull on the small handle that was designed as a lock (that afforded turning but not pulling). The assumption behind having a plate on one side and a handle on the other is that there is a default position for the door, which could have been achieved if the "system" (aka the hinge) was set up to automatically close the door. But it didn't. In this case, the user has to both pull and push the door to get it to the desired positions -- and yes, privacy is valued by most of us in this situation, so most do want to be able to close the door as well as open it!

I've previously commented that we seem to be unable to design interactive devices as simple as taps; it seems that this extends even to doors... and I don't think interactions get much simpler than this.

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