Home Updates Messages SandBox

Cursor in User Interface

The evil cursor

You must have noticed this: cursors are everywhere today. You want to change your @VCR@ preferences? Change the brightness of your monitor screen? Set your alarm clock? Open door in your favorite computer game? Write an article for your blog? Use your cellphone? There it is, the cursor! At the same time a large part of the population does not understand that metaphor: pressing buttons to move a blinking rectangle, or arrow, or icon, or game character, and doing things with it indirectly. I have seen it many times: people fumble on cursors, they do not see the correlation between pressing the buttons and the cursor motion, it is random for them, they just press buttons until they manage to get it to the right place somehow. Sure, I know what you are thinking: if they are too dumb to handle a simple cursor, then they should not buy electronics. But note something else: if there are people who can handle normal buttons and knobs and levers, but fail to operate cursor-based interfaces, then maybe, just maybe, the cursor-based interface is in fact considerably harder to operate?

Powerful metaphor

It is interesting to see how cursor-based menus are similar to computer games. Especially to the ones with third-person-perspective view. Basically, you use a few controls (usually keys or joystick) to control your avatar, your representation in the internal world of the device. Whether it is a richly animated image of a hero or a blinking white square, it does not matter: the ancient computer games also used blinking squares, after all.

So what we have here? A rich and complicated real world in which our bodies and senses are, a complex and unexplored internal world of options, possible actions and parameters inside the device we try to control, and a simplified physical interface to use, usually consisting of only few buttons and a small screen; sometimes the screen is even replaced with just a few blinking lights. On one side a capable user, on the other side a rich world, and in the middle a barrier with just a little window in it. That window can be moved to access all the richness of the world inside the box, but only one small piece at a time. This is usually called the keyhole problem.

A man that was a bicycle

It is a well known fact that we blend with the vehicles we ride: you mount a bicycle, and it becomes part of your body. Decent drivers have the same experience with cars. We can even observe similar phenomenon when using a simple tool like a nail file: it becomes an extension of our hand. People playing computer games often have similar experiences: they project themselves into the game world, become their avatars. They are no longer sitting in front of a computer, they are inside the game world, fighting monsters and saving princesses. Somehow they are able to transfer their consciousness, through the few buttons and monitor screen, into the simulated world. It does not really have to be a realistic world, in fact we do it when playing realistic computer role-playing games as well as simple puzzles. We no longer command our avatar, we become it.

How do we do it? There are several prerequisites for it. First of all, we need to know the controls. Not only have them learned by heart, we need to have them trained into us; not memorized, but carved right into our hands and muscles. This is often called habituation. And of course the controls must react in expectable ways, you need to be able to anticipate the results of your actions. After all, if it does not do what you want, how can it be part of your body? Even if there is a failure because the command was wrong and impossible to perform, there must be some indication of that, and it must happen within very short time, best less than 100 milliseconds, otherwise we get kicked back into the real world.

Turtles all way down

Things can easily get out of control: once the user feels the cursor as if it was part of his body, you can abstract the interface further and use… another cursor, controlled with the first one. Isn't it obvious? Well, it is not. Actually I have seen this once: It was a computer role-playing game. You controlled the game with your mouse cursor. You used this cursor to control the main character, second cursor. There were puzzles in the game, and one of them involved a huge crane the character could control, third cursor, by stepping on a number of buttons on the floor. The goal of the puzzle was to arrange colored blocks, fourth cursor, into specific shape. I think I do not have to say it: the task that would normally take a fraction of second for a 6 years old child turned into a hard puzzle in the game, by just mere introduction of several layers of indirection. Good thing it was only a game.

We can observe the same thing everywhere, even in the brightness controls of your monitor. Also in software: you have the mouse cursor, the text cursor, the selection, etc. Every level degrades our dexterity, requires more concentration and generally takes away more control.

Where are you?

To be continued…