Indeed. It's like walking. You don't think you are walking, you just walk.
Everybody can teach his/her muscles to act "on their own" for a task as simple as this without that much practice.
I'm not sure how you can teach one's muscles to act "on their own" without too much practice. Maybe if one were trained by injection, Matrix style. :)
I wonder if mouse + keyboard input could be augmented by head gestures? NaturalPoint sells an economic mouse that can be operated by placing a reflective dot on a pair of glasses or a hat. What if instead of being a mouse, this could be an entirely alternate input device? You could read head gestures in the same way that the Wiimote detects different movements. These gestures would likely become "muscle memory."
This is also why I switched from T9 to whatever the other alphabet-entering system is for cell phones: it was just too frustrating not to know exactly what the output would be if I typed quickly.
I wonder how this over-learning might be related to reading behavior. I'm sure we've all seen those sentences where the author transposes the middle characters of each word while leaving the first and last characters the same; the sentence is suprisingly not difficult to read. Maybe in the same way our brain has a "good-enough" pattern matching behavior while reading, it quickly recognizes the pattern of the word we're typing and says, "I know this one, I'll take it from here."
Watching the experienced users using that interface is just amazing. They don't read the menu items; they know which direction is what by heart, probably in muscle memory.
I guess you could argue that without some speed, you can't really say you've learned something (what's the point in playing "Voodoo Child" at snailpace?), but the threshold is still there.
I wholeheartedly agree. I have become a 'keyboardist', as it were, just by using what I needed.
If you find a shortcut for something you use often, eventually you'll get used to using it, not because you want to, but because it'll feel natural to.
Muscle memory is always instinctive, it's hardwired in the human brain. Everybody can teach his/her muscles to act "on their own" for a task as simple as this without that much practice. (Remapping your keys in your keyboard helps a lot for comfort.)
But it's hard to get there, you have to find the commands, practice them, practice, practice, and all the while it would be easier to just reach for the mouse.
I think the trick is to forget about "practising" and just do it. If the command is really helpful, you'll end up using a lot anyway, but the mindset is different (forced practise vs need).