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What Is Important In A User Interface?
fosh asks: "Out of some discussions going on in response to the Gnome-Microsoft connection I have come to ask myself, (and the Slashdot community) the following question: What is really necessary in a User interface? What is the set of elements that is required, what are the elements that make the user's experience better? What are the inherent problems with MacOS, Windows, Gnome, KDE? Why are computers still hard to use for people like my mother, and how can we make this better?" Of course, the words "user interfaces" usually means "visual user interface." Voice recognition has come a long way in 10 years, and in another 10, we'll probably be able to talk to our machines in plain...well...anything! When this happens, will these ideas still hold merit?
Consistency is a primary feature for most users; "easy" is often irrelevant, because beginners end up using a cheat sheet of some sort anyway. Consistency is one of the things that allows rapid learning, and is vital to the success of an interface among non-expert users. It's actually fairly valuable to experts, too.
GUI? CLI? Voice? Who cares! The key thing is that:
1. You can get a list of plausible options in most cases. The list may be a bunch of icons, any of which you can click on. It may be a dock. However, somewhere, there should be some kind of guide to what your choices are.
2. There will be cases where no such list can be made, because there are thousands of entries; in these cases, a little sorting goes a long way.
3. You must be able to pick an action unambiguously.
4. You must get feedback as to whether an action has succeeded or failed, and if it failed, you should get an indication of what prevented it.
5. You should be able to control the level of feedback based on your needs.
6. You should be able to abort unintended actions. Undo is nice, but abort is absolutely essential. For newbies, dangerous actions should come with a clearly labeled delay during which an abort will be harmless.
Most UI's try for some portion of some of these. Some attempts to make "easy" user interfaces end up falling down. How do you rename a file on a mac? Click on the name and wait a while, and it becomes a text box. However, if it can't be renamed, no one tells you, because there's no reason to believe that you really meant "rename", not just "select", and it would be stupid to give you the warning if you were just selecting a file.
This gives us also:
7. Explicit actions are preferable to implicit actions. You should always know what the computer thinks you're doing.
My blog: http://www.seebs.net/log/ --- My iPhone/iPad app: http://www.seebs.net/seebsfrac/
But a few big, important things:
- Ease of learning - steep learning curves bother people!
- Power - it must accommodate both novice and advanced users (scripting is good here)
- Consistency - users should be able to use new programs without having to relearn a new interface each time
- Response speed - it must respond quickly when the user tells it do do something
- Efficiency - it must allow the user to complete tasks quickly, rather than getting in the way. This is one spot where Windows has really failed.
- Aesthetics - yes, most people care about how pretty their desktop is (me included)
- Appropriateness - the UI should reflect the task it was designed to facilitate. For a computer, this means it must be flexible enough to allow many different kinds of applications to work
- Flexibility - both for different types of tasks (word-processing really is quite different than video editing), and different kinds of input devices (why can't I use the joystick to navigate programs?)
- Predictability - things should do what they look like they'll do; nothing more, and nothing less
- Context - the UI should give obvious context to the user, so they'll know what they need to do. Conversely, it should also provide simple and easy ways for the user to specify a new context (multitasking, etc)
That's only a few things which matter, but hopefully it illustrates the difficulty of doing it well...I think one of the major requirements for a user interface is a very hard one -- it has to simultaneously:
(1) Allow newbies to understand what's going one and learn (e.g. menus);
(2) Allow casual users to use "standard" skills in an application (consistency across applications);
(3) Allow experts to use fast but nonintuitive ways (e.g. keyboard shortcuts) and to considerably modify the user interface if desired (e.g. remap keyboard).
(4) Allow a smooth progression from the newbie status to the expert status (newbie and expert should not be two completely different interfaces).
Kaa
Kaa
Kaa's Law: In any sufficiently large group of people most are idiots.
Pieces of paper on a desktop?
This is one area where I think a lot of the open source tools get it right. A good example would be the utilities that are available for burning CDs under Linux (and other operating systems) such as mkisofs and cdrecord. These tools provide the functionality that you need to premaster and record CD-Rs on the command line. Then you've got software such as xcdroast that essentially acts as a graphical front end; when it needs the services of either of the previously-mentioned pieces of software, it simply opens a pipe to them and lets them do the work. The result is that if you prefer working with a command line (as I do), you're good to go. If you prefer working with a GUI, you're still good to go.
In many ways, this type of architecture is an extension of the classic paradigm of Unix tool development: have a lot of tools that accomplish small tasks, and have the ability to chain those tools together to perform more complex operations. Only in today's environment, "chaining together" often involves wrapping a functional GUI around them to make them easier and more intuitive for users to navigate. This type of architecture really does offer the best of both worlds; it gives users the tools they need to perform a task, and it offers them a choice as to how those tools will be used.
We're going down, in a spiral to the ground
Having different interfaces (e.g. voice recognition/GUI/command line) is vital for a usable computer. So is being able to change the interfaces you are given. MS (as well as other companies) don't seem to be aware of this fact.
"Why are computers still hard to use for people like my mother, and how can we make this better?" Hmmm...then she'll find all my porn. I wish not to make this better.