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May 4, 2003
The natural perversity of inanimate objects
I just finished reading The Design of Everyday Things by Donald A.
Norman. I was very impressed by the logic of the points he puts forward in
it, and the clarity with which he does so. A sample of the principles he sets
forth:
- Make it obvious. If you're designing an object, think about what you can convey to its user from its appearance. Provide "knowledge in the world" by means of affordances. If part of it needs pulling, provide a handle that suggests a pulling motion when you put your hand on it. If you're making something with a control panel, don't make it modal, or force the users to go through complicated button sequences for the sake of having less buttons, when a larger number of clearly labelled function buttons will be easier to use. Put the controls in a formation that suggests a relationship between them and what they control, so your users won't have to think about which one to use.
- Reduce choice. If something needs to be connected to or inserted into something else, shape it so there's only one way to do it. Arrange controls into logical groupings, so your users don't have to search through a horde of buttons or menu options to find what they need. Reduce the decision tree of using your object to a narrow one. If necessary, use a forcing function to make them do things in a particular order, but beware of annoying them.
- There's no such thing as the average user. Don't assume anything about the people who will be using your object.
- Learn from users' mistakes. If the people testing your object (you are testing it, right?) keep doing something wrong, take that as a hint you should change your design so it doesn't happen any more.
There's a lot more than just those; an excellent summary can be found online
on
page about cognitive design principles. None of what he advocates has dated,
despite having been written in 1988; however, a couple of references to
"current technology" are slightly problematic for today's reader, such as
Even the largest screens now available can display no more than about
two full printed pages of text. Also, he muses on the coming uses of
hypertext (for the Web was, at the time of writing, two years shy of coming
into existence):
Imagine someone trying to write something using it. The extra freedom also poses extra requirements. If hypertext really becomes available, especially in the fancy versions now being talked about - where words, sounds, video, computer graphics, simulations, and more are all available at the touch of the screen - well, it is har to imagine anyone capable of preparing the material. It will take teams of people.
However, the next sentence hits it right on the button: I predict that
there will be much experimentation, and much failure, before the dimensions
of this new technology are fully explored and understood. We're still
experimenting to this very day.
In conclusion, I'd recommend The Design Of Everyday Things to
anyone who's involved in designing something for other people to use. It's a
masterful piece of work.
Posted by hex at 3:54 AM |