Psychology + Architecture
There are two problems to consider here. One is psychological, the other is architectural.
The psychological problem is that we, humans, don't perceive space objectively. Like every cognitive experience, it is unique to each one of us. At the same time we have our biases, often thinking that space is different from what it really is. The branch of science dealing with this problem is Spatial Cognition. And if this sounds at least slightly interesting to you, Colin Ellard's book is a good introduction to the concept (he's got a TED video, too). One interesting thing you can find out from him is that animals see and feel space completely differently from us. You can see this lecture about ants for example - and I must admit that recommending it to people always makes me feel very geeky (so click here to un-geek yourself).
So basically, the physical space is more than just walls you see and lines you draw on our human maps. If space can be felt differently (as a huge map of Earth's magnetic field by pigeons for instance), it should certainly be possible to represent it differently. And in fact we're animals too and we feel much more aspects of space than we can see at any given moment. Space has many aspects we associate with it. In result, we rarely act logically in space - and if you ever realised the route you're taking from home to work isn't the shortest one when you look at the map (but you like it more, or it feels easier, or...) then you know exactly what I'm talking about here.
And here comes the architectural problem. We're very much used to mapping space through the traditional maps and floor plans. They are very precise and they capture the information we need in a very detailed way. Too detailed perhaps. The idea of Space Syntax is to zoom out a little and look at more general patterns (see slides 1-9 from my presentation further below). Because, you know... if we map our buildings with detailed floor plans, each of them is unique. It's physically impossible to build two structures that will be identical to the last millimetre. So if all of our buildings are different, how can we come up with any research conclusions that would be valid for more than the one single building we have studied? In this classic video, the founding father of Space Syntax shows a bit of spatial analysis - notice how details of these streets (their width, what they're made of, etc.) are ignored to emphasise some other aspects - in this case their relations between each other. If, after seeing and reading all this you still don't think we're all crazy, you can watch another lecture, to see how similar techniques reveal how IKEA controls its customers' movement.
And of course it's not like all these problems only appeared now - XX century wasn't the most happy one for architects and urban planners, and these has stimulated some really cool studies (like the one here). All that Space Syntax tries to do, is to find out how to quantify these ideas - how to measure them, calculate them and compare one versus another. And all Spatial Cognition can do here is to keep track of what effect these changes will have to our final perception of space.
Mobile Eye-Tracking and Isovists
The sense which most likely contributes the largest amount to our understanding of space is vision. The vast majority of us cannot imagine operating in space without it. But the science still doesn't understand exactly how vision translates to what we feel about space. Of course - a sign, or an advertisement get noticed when you look at them, but there is more to it.
Just try remembering the last time you walked into a gothic cathedral, or a large mosque. That 'oh-wow' feeling you most likely had comes largely from vision. But not necessarily from the exact object you fixated your eyes at in the given millisecond. The experience is much more dynamic than that. You were outside, you saw the shape of the building... then you walked through some doors, possibly a narrow corridor... and then you had a vast space quickly opening in front of you, right there.
So designing buildings with vision in mind is so much more interesting than just picking the location of specific elements. It's about the whole experience unveiling in time.
And there is a theory that represents this - 'isovist' and 'isovist fields'. The idea is, that we can mathematically describe some aspects of the environment which affect our visual experience of space. But there is one problem - we don't exactly know how these mathematical descriptions affect us in the real world. Finding this out is one of the most exciting parts of my work. See the section on Art Galleries for some examples.
Architecture as interaction
Coming from human-computer interaction background, my approach to architectural experience is to understand it as interaction. This means that every (visual or any other) encounter between you and a piece of external environment is a two-way process:
You have the ‘power’ over it - you can decide to move around an obstacle, jump over it, or squeeze underneeth. While searching for a room in a new public buiding you can take left, right, or the middle corridor. You decide.
That’s one way.
The opposite way is the impact this architecture has on you. By its look the obstacle might ‘suggest’ you to jump over, making this decision more likely than any other. So even though you have a choice and you have the ‘power’ over the actions you take while exploring the environment, the enviornment can make some of these actions more likely than others. The left corridor, out of all three, might be just a bit wider, and straigher - therefore a person searching for something would be more inclined to take it. We rarely realise these little things work on our decisions so often. The real problem occurs when they are not consciously designed elements of the environment, but rather a random side-effects of the design process.
Just like any other interaction, the really successful environmental interaction ought to be seamless. Ideally, we shouldn’t (or needn't) even know that the environment has affected our decisions. We should just be able to get to where we want and do whatever we are there for. Without even knowing how it has happened.
What is a usable building? How do we design one? Can an architect ever know what are the real needs of building users and how to meet them? Is it better to have a school precisely designed according to the best knowledge we have about schools at the moment, or to have a flexible building, where the arrangement of classes and areas' function can be flexibly modified by its users?
My angle is a bit different. I'd like to know if usability needs designing at all. It certainly does need it in the area of computers and technology (and this is called Human-Computer Interaction, or HCI) but in there everything needs designing, as they are all manufactured objects. The case of architecture slightly differs, as for centuries people where doing a decent job designing, building and adjusting their own houses without anyone telling them how to do it. This phenomenon still exist and can be often observed in squatter areas of many countries where no formal planning exists. People are thrown into self-finished structures and they have to make their living in there. Often, these places become their homes for a lifetime and as such become quite homely indeed. I had a pleasure and honour to be a guest to many gecekondus of Istanbul and they definitely felt nicer than many modern flats stacked on top of each other, connected by white, hotel-like soulless corridors. Is there anything about how these homes fulfil their function - how usable they are, that we can learn from them?
To answer some of these questions: yes, I do believe usability needs designing probably everywhere where a human designs something for another human. But I also think the most usable solutions can be spontaneous and the design should never put limits on that. I've been to too many modern blocks of flats which look like hotel corridors. Something went terribly wrong here.