This article from Wired talks about how your mental attitude affects your behavior.
. . .“Our results indicate that beliefs about free will can change brain processes related to a very basic motor level,”. . .
. . . To lose confidence in free will seemingly introduced a lag between conscious choice and action. . .
My sense is that studies such as these are so very preliminary that drawing hard conclusions on the specifics can lead you astray, especially on topics as controversial as free will. But I do think that they empirically reinforce the common sense idea that your attitude and general mental state as you go about something like making music is going to affect the outcome.
The neuroscience is telling us that it's the simultaneous coordination of many areas of the brain in music making that makes it such a unique behavior. Maintaining continuous awareness of all that can be tough sledding, and I think the concept of mindfulness as put forward by Tibetan Buddhism can be one very useful way of talking about how to go about it.
A big part of mindfulness is simply observing your thoughts, emotions and behaviors without feeling you're having to make immediate conscious decisions and judgments about everything all the time. In making music this involves being as good a listener as you can be to what you're doing, as well as to those around you if you're in an ensemble. Taking the time to have a better sense of the music as a whole can help you understand what adjustments you want to make on the smaller scale.
One thing about practicing mindfulness is that like anything you practice you can get better over time. One thing which sets high level players apart is their being able to hear and respond to the music they're making both as a whole and in its many parts in real time. For those of us not at that level, understanding that how we're thinking and feeling about making music has a lot to do with how successful we are. It's another way of framing the musicality vs. technique duality.
One thing that can happen as you work with being more mindful is that you become aware that there's more going on in your behavior than you're usually aware of, and that some of it is merely reactive and routinized. A classic example in music making is rushing when playing passages perceived as difficult. Usually it's anxiety kicking in and highjacking the tempo. Coming to realize it's an anxiety issue as much as a technique one is half the battle.
Another point to make about mindfulness in the Tibetan sense is that it has to do with feelings and emotions as well the more rational connotation it has in the West. A Tibetan saying someone has a good mind is like a Westerner saying someone has a good heart. So in music making this means being open to the feeling/emotion content in real time, as well as the technical issues.
My Friday group has both professional level and amateur level players, and all the amateurs have approached me at various times to say they've had more fun and gotten deeper into making music in this group than any other they've ever been in. I think a lot of that has to do with arranging the music to suit their abilities, which allows them to be more mindful the musicality side of things. That means they can lay down a solid framework for the pros to use to take improvisational flight.