Knowing how we process information helps us design better

Recent researches on human brain suggest that the way our brains works is fundamentally different from the way computer works. Difference? Computer receives an input, processes it based on yes/no (1/0) and comes to a conclusion.

On the other hand, when brain receives stimuli, it recalls similar patterns from the memory and try to predict the consequences. So based on our experience, patterns and expectations build up among us. [1] '. . . we're always trying to fit what we're sensing to what we know'[2]

I don't research on brains and I don't know whether above arguments are true, but it makes a lot of sense to me.

From the perspective of information architecture, it is extremely important to structure the site in such a way that helps users build a mental model of the site easily. That is to say, helping them build up correct expectations and making the site work like how they expect.

If, for example, one button behaves differently depending on the context, users will have a difficult time knowing what the button will do next time when s/he clicks. After few clicks they quickly become frustrated and discouraged to use the site. Along with misuse of metaphor, the use of a trash bin icon on Mac OS (pre-OSX) was often referred to as a good example of this mistake. (To eject a floppy disk, user had to drag&drop an icon of floppy disk into a trash bin. some users got confused and it made them worry the data would be deleted)

Usability testing is important and there are several tools which you can install onto your site to record the users behaviour (so scary it is! it's an infringement of privacy!). But without knowing how to use labels properly or categorise menu items appropriately, having abundance of test results means a little. Understanding how human understands information and also knowing general user behaviour will give us great hints on how to improve usability and findability. Without such knowledge, you will only get so far (and so I'm studying hard!).

References:
[1] On Intelligence by Jeff Hawkins, ISBN 0-8050-7456-2
[2] http://www.mindhacks.com/blog/2004/12/hack_102_alter_in.html