Have you ever wondered why you are able to open a door?
What sort of dumb question is that, anyway? Of course not. Opening doors is completely natural. All of us are able to do so. It takes no special skills or abilities (above basic motor functions, anyway) and anyone can do it from the time they are tall enough to reach it. You might say that opening a door is completely intuitive to you.
So why is that? Why is it considered intuitive? If you were a martian seeing a door for the first time, you would not be able to understand them. But once you've seen it demonstrated, you can open any door in the whole world, even doors you have never seen before. For something as ubiquitous as doorknobs and handles, it turns out that a whole lot of design and thought have been put into it to make them as non-intrusive and simple to use as possible.
Yet it's still entirely possible for designers to muck it up in such a way that there are doors that can be hard to use as well. Yes, we humans can get stumped by a door. In grade school we used to mock each other saying "It takes an IQ of fifteen to open a door" but in reality it is the opposite, it takes a large amount of intelligence to design a door that is easy to open.
When I moved to America at the age of six, one of the first things I noticed was that doorhandles were different. Or rather, there weren't doorhandles, there were doorknobs. In Norway, I was used to a lever to pull down on to open a door, while in America I ran into doorknobs, circular objects protruding from the door that had to be turned to open. To the six-year old me, this was fascinating. (But due to being six I didn't spend too much time on it then.) Didn't take me long though, to understand the new doorknob, as the basic motion was the same. Twist something around the central axis, whether it be a circle or a lever.
We are able to operate the doorknob itself intuitively, having learned how to do so over many years of practice. Now how about the door itself? Are you supposed to pull it or push it to open? When approaching a door you have never seen before, you don't know that. Fortunately, your brain is smarter than you are, and as you approach the door it scans for any hint as to which way it opens. There are a number of hints it looks for to decide whether to push or pull.
Firstly, are there signs? Does it read 'Push' or 'Pull' on the door somewhere? (If the door designer had done his job properly, those signs would not be necessary. You should understand easily what direction a door goes.)
Secondly, most doors open outwards. (Towards the exterior of the building, even for interior doors) Or at least they should. I see examples where this is not the case almost daily. This is a good idea for fire safety in public places where a large amount of people can gather. If there is a rush to the door, it better open outward, otherwise once people gather by the door it will be impossible to open due being blocked by the people trying to get out of it!
Thirdly, we look for a heavy doorframe. We know that matter cannot pass through other matter, so if there is a big frame surrounding the door, most likely the door opens the other way. Fourth, we scan for hinges. We know that hinges have to go on the side of the door in which direction it swings. If we see hinges, we know the door opens that way. If we do not see hinges, we can assume the door opens the other way.
All this happens, as with most of the brain's activities, without you really realizing it. Of course, if you try the door and push down the handle and it won't open, immediately you try the other direction to see if that happens. Time lost a fraction of a second.
But there are plenty of examples where this is not the case and you can indeed fail at opening a door. Imagine a fancy new office building. Three sets of glass doors are next to one another. The architects did a fine job at making everything look pretty, which involves hiding doorframes and hinges. The doors can be locked but it is not visibly apparent if they are (they lock in the hinges). There are no twisty doorhandles, only a handle to grab to pull. You come in and grab one and pull. The door doesn't budge. You try to push, also to no effect. Dumbfounded, you try one of the other doors, and fortunately it opens, inwards.
This was a visit to my local bank. Their first mistake was to lock some of the doors during non-peak hours operation. There are no visible signs that the door is locked, so you assume that the door is indeed open. Second, a grab-handle like pictured above is not very conductive to pushing, your first instinct upon grabbing that one is to pull. Much better in that case would be to remove the handle entirely - if there is no handle you can only push, not pull. Placing a small metal plate in about hand height would also be a nice indicator for "push." Thirdly, in public places like that you expect the door to be open, so all the doors should be open in hours of operation.
Using small hints like these we can easily deduce how the door is going to open, provided of course that the door is not actively trying to fool you. But even automatic doors are not immune to this. At a subway station in Oslo, Nationaltheateret, they have (or had, I have not been there in some time) a horrible setup for their automatic sliding doors. "But Bendik," you say. Sliding doors open neither inward nor outward and they are wholly automatic, so how is it possible to do wrong there? Well, through sheer human stupidity, they managed to cock it up quite nicely. The doors had arrow stickers on them. Allow me to describe it, as I unfortunately do not have any images from there.
There are three sets of sliding doors next to one another. Each sliding door is in three layers. Thus when all three doors are open there are still two areas where the doors have slid to, so you cannot walk there. (Like some fenceposts) So far so good. If the doors open sufficiently early when I come walking, I will see where the opening is and walk to it. Unfortunately, the range on the detectors here was quite small. You had to be about 1.5 meters from the door before it would detect you. If you were in a rush, like you are wont to do when trying to catch the subway, you could easily reach the door itself before it was fully open.
But the main confusion came from the arrow stickers. I suspect they had problems with people failing to hit the door opening properly, and put stickers on the doors indicating where you should go. When the doors were closed, you would have arrows pointing like this:<- <- <- -> -> -> <- <- <-. The first time I arrived to that station I had to stop and wonder, do the arrows indicate where I should walk, or do they indicate which way the doors move to open? Turns out, it was the latter. Fortunately, during most hours of the day, Nationaltheateret is a busy enough station that the doors are just about perpetually open, or at least you can see which way it opens from the previous person walking through. I had to do this for two years when I used that station daily. But when I came during off hours I would regularly get outsmarted by these doors, making me almost walk into them when they opened a meter to my left. In this case I was not able to open a door properly. (I believe they have fixed the doors so they are better now and possibly reorganized or even removed the arrow stickers. If any readers frequent Nationaltheateret I would love to hear how it is today)
So yes, it is possible, and slightly too easy, to make a door which is hard to open. A lot of smart design has gone into making it all totally transparent and intuitive for us. There is nothing absolutely intuitive about a the mechanisms that go into opening a door (if say, a martian had come to observe it) and no two doors are the same. Yet we pull it off (usually). Or rather, your brain does. Doors can swing inwards, outwards, or slide. Your brain figures it out based on all the factors it sees.
Think about that next time you walk through one of the many doors you use flawlessly every day in your daily life. It's mostly thanks to the brain's impressive cognitive abilities, transposing experiences from one place to another.
Most of this post was inspired by Donald Norman's book The Design of Everyday Things, and Steven Pinker's How the Mind Works. Both totally recommended.