The left and right hemispheres of your brain have a complex relationship, and that relationship facilitates how you function in every aspect of your life including how well you play jazz.
I like to talk about the roles each hemisphere plays in creating art, specifically jazz improvisation. Think of the left side as the analytical verbal facilitator and the right side as the non-verbal, intuitive creator. Both play a critical role in the final artistic process, and as long as they as properly integrated, the artistic result is optimal.
I created a funny short animation showing how the left analytical side of your brain can mess up your artistic right side.
The integration begins with your brain's left side figuring out the mechanics of playing your instrument. It discovers where middle C is on your instrument and then learns the various notes required for the C major scale. As part of its learning, your left side is listening to the sound of C major and then hears the individual notes of the C major scale. It then labels each of those vibrations with a letter designating each note. A C-Eb-Bb.
If you choose to dive into more music theory, the left side starts to hear and then learns the vibrational differences between minor seconds and major seconds. It ‘hears’ those intervals and allows you to talk about these basic elements of music harmony. Perhaps you dive into theory even deeper and discover the fractions designated to a divided string. You start to use the word ‘physics’ to describe the moving air molecules caused by contact with the string. You're becoming well-schooled in the mechanics of jazz.
Your left side is working hard to understand music (and the world at large).
On the other side of your brain, through repeated listening and thinking of all this, the right hemisphere is absorbing all this listening and theory so that you don't have to constantly relearn things over and over again every time you wish to play a C major scale. And you'll recognize the vibrational sounds of the frequencies within the various tonalities. All this is way too much to hold on to consciously so the right brain hemisphere retains it subconsciously.
Recollection of the knowledge and sounds is now in autopilot.
It may require a lot of repetitions before your right arm extends the trombone slide to fourth position to play middle C, seemingly by itself. But at a certain point in time, your right brain says, “I’ve got this.’ The ‘baton has been handed from the 'thinking consciously about things' left brain to the more powerful right brain.
Consider the act of sending a text to someone. Are you hunting for the letter ‘o’ each time you need it? Or even thinking about how to spell the word ‘or’ each time? No, of course not. At one point several years ago, that left-brain thinking about the individual letters, their placement on the keyboard, and the spelling of common words got handed off to your right brain hemisphere. Those activities became automatized.
Now that your knowledge of letters, their placement on the keyboard, sentence syntax, and spelling have all become automatized, you can now call on your left analytical brain hemisphere to consider higher-level concepts like writing a blog post on brain function.
Similarly, once musical pitches and their placement on your instrument have become automatized, you can dedicate left-brain resources to manipulating those pitches to create melodies. Once your right brain can take over creating melodies not requiring the conscious thought of one note following another, your left brain thinks about the sound of certain notes and motifs over combinations of pitches known as chords. You are becoming more sophisticated and capable as a musician.
Are you seeing the progression of left-brain learning and thinking, and how that function gets handed over to the right brain? Eventually, for a master jazz musician, the entire sequence of events leads to perfectly pitched and articulated melodies flowing over a wide variety of harmony and rhythm that you recognize subconsciously.
Think of how silly it is to imagine Miles Davis thinking to himself, ‘Inhale then play a mezzo forte E right now for the duration of a quarter note using the open valves released with a slight downward pitch effect.’
As silly as that sounds, many jazz players are doing something similar when they think chord to chord as they improvise over a harmonic progression. "G7 is next so I should play the G Mixolydian scale throughout its duration.”
What is the solution to left-brain consciously thinking your way through an improvised jazz solo?
The answer is to do the left brain preparation work called practicing in order to automate the sound of G7 along with the sounds of all 12 notes and their relationship to that chord. It’s a function of listening. Deep listening.
Consider all the daily activities that you no longer think about like putting a fork into your mouth, tying your shoes, putting your shirt on, or even walking. Believe it or not, there was a time long ago when you had to think about those simple processes that now live comfortably in your right brain subconscious. Those skills are now instantly available whenever you need them.
Of course, the hand movement used to tie your shoes is much simpler than creating an interesting melodic line on a tenor sax while hearing E7b9 from a rhythm section. But the principle is the same, and it’s also why so many more people can tie their shoes than play jazz well.
In my encouragement for jazz players to listen and play rather than calculate their solos, I don't always talk enough about the necessary fundamental preparation of that routine left-brain practicing. Despite some educators advocating for mastery with no effort, a lot of effort (practice) is absolutely crucial to playing authentic meaningful jazz fluently on your instrument.
If you’ve never ridden a bicycle, simply admonishing you to stay present and visualize speeding down the road will most certainly end up with you falling and hurting yourself. Using training wheels and having someone trusted holding you up for a while is the necessary baby step practice for your left brain. Little by little the success of staying upright builds stronger and stronger neural connections so that the required muscle movements seep into your right brain so that it can automatically take over the balancing part of riding. Now you can reassign your left brain to turning your head to looking around and navigating next-level skills.
Are you getting the idea? Your left brain does the initial grunt work that, once accomplished enough times through repetition having built the necessary neural connections, hands the task off to the right brain for autopilot. We are in a constant state of doing the initial learning, repeating it enough for it to become automatized, passing the activity or knowledge to the right brain subconscious, and then moving on to another beginning stage task or understanding.
Without the necessary repetition, you’d be at the mercy of the left brain to calculate all the moves all the time. Why do all your solos sound similar and robotic? Because you’re still thinking about which notes to play. You may not be consciously hearing yourself say, “A, B, C, Db…” as you play, but your musical instincts aren’t yet automatized fully enough so that you can simply feel an emotion or thought that becomes transformed into musical lines.
This automatizing of musical performance is a life-long process. It might end if you are satisfied with your routine of playing your particular style, but for those players who are striving for more authenticity and a connection to deeper and deeper reflection of their emotions, it cannot end. Art provides way too many options-virtually unlimited rhythmic and melodic combinations, and virtually unlimited emotions brought about by your personality and life circumstances.
In the end, you must practice to increase your skill on your instrument and listen to music and its various melodic, rhythmic, and harmonic components so that more and more can be handed over to your subconscious right brain. After all, it's far better at making the best music of which you are uniquely capable.
I'll leave you with this clip of psychologist Dr. ttRodney Brim talking about the left and right sides of the brain, and why traditional education has a difficult time teaching improvisation well.