theory, in many sense...r just labels for the sounds.
Exactly; if we take note-names, eventually as music gets more and more complex we lose the ability to recognize individual note-names. When we read music, we start to recognize something like the shape of the notes on the page, rather than thinking "D.. A... ummm F#... and D!". We can then label these groupings, and so forth. What we end up with is something for our brain to create references to; they may not be an immediate thought as we are playing, but if we slow it down we can recognize all the separate notes and how they work together, and I think this helps make the end result 'clearer' in the mind.
Some people improvise with these things in mind and others have no "theory" except their ears. I belong to the latter group but everything in music is a choice, an option to use or reject according to the quality of resulting sound. If it sounds good it can't be wrong, however it was created. Interesting improvisation is all that matters in the end, whether a theory is used or not.
I've only included the last part of this post here, but I found the post in its entirety very good! I'm in a rural area, and there are an awful lot of 'polka' players, and the vast majority of them can't read a single NOTE of music. However, they can play back hours upon hours of music, and it doesn't matter what key you may start in; most of them will follow you, despite not knowing anything about theory. It just shows the power of a well developed ear. Of course, polka's generally aren't exactly the most complex forms of music, but it's still an impressive feat, though one that I feel is more attainable than people like to believe.
University programs push both aural skills and theory, but there's a lack of displaying how they can work together on an instrument to maximize your potential. Being able to pass an aural skills class doesn't mean you can successfully demonstrate it's usage on an instrument. Practicing theory and aural skills ON the instrument of your choice also brings in the ability to reference these things to physical feeling, the visual, etc... My experience with the classes was that it taught with good intention, but what 90% of the students got out of it wasn't helpful, because they never learned to apply any of it to their playing. On the other side you get many people that have never taken an aural skills class in their life that can play wonderfully by ear because they focused on applying it to their instrument.
When I improvise I sometimes get the distinct feeling that my right hand 'knows' where to go because it is following scale and arpeggio patterns.
One problem is that when I perform, 101 other things come into my mind. Usually silly, banal, day-to-day things. I wish I could train myself not to do this! Perhaps I need a psychaitrist or a personal trainer!
This is my main experience with theory in improv; my hands (especially the right hand) seem to 'know' where to go based on my practicing scale patterns, though the actual break-down of the scale, or even the scale's name may never enter my mind. I feel as though I let my ear take over to navigate the scale even though I may never realize what scale I'm playing in.
On the second point, performance gets to be a nightmare with all the 'chatter' that comes in to play before and during your playing! It gets to be exhausting as all these things continuously run through the mind. I've found that if you can find something in the music you can confidently concentrate on, it allows you to center in on that and everything else seems to get pushed to the back of your mind. It also boosts your confidence and lets you feel as though you can better express yourself to the audience, making performance a more fun experience. This may sound redundant, but I've recently made a push for concentrating on phrasing and sounds within the music rather than the fingerings, feelings of playing, etc... as it's something I feel more confident in remembering. The fingerings and such come naturally as they're all referenced to the music anyhow, and you won't be so nervous about forgetting individual notes, why the piano looks different with the music stand down, etc... Too much stress is not good for memory recall!
This may also open up the discussion to further things related to playing with the ear. Connecting the ear to the physical isn't just limited to being able to recognize pitches and where they are on the keyboard. The idea of using your ear to control fine motor movements isn't new; Abby Whiteside made a case for it with her idea of a 'central rhythm' (just an example). Building technique based on referencing motions to the ear and your sense of rhythm may be very useful for opening up new doors to people that are stuck, having explored many other areas in trying to develop their technique.