It's not a mystery, as is often said, but it's very complicated. And it's physical as well as mental. The two are totally intertwined and can't be separated.
Just saw "Big Mind." Truly weird video. I don't think you can expect this to happen in more than one in 100 million cases. But it does bring out several relevant points: this guy memorizes and calculates the same way we memorize and make calculations about a piece of music: via signposts--tangible, kinesthetic signposts. I'm not comparing myself to this guy in any way (what he does is totally miraculous), but I can say that my brain works the same way when dealing with music. Keys have definite colors for me.
Rachmaninoff's Third Concerto is deepest darkest emerald green, as is almost everything in D minor; A minor is well-nigh black; E flat (the Emperor concerto) is definitely bright golden; whereas the fourth concerto has always been a little spoiled for me by the fact that its color is a rather bland brown. I will never touch the second concerto, as that is in B flat, a really sickly yellow key (though that makes Brahms' B flat concerto a problem for me, as the music is so fabulous), nevertheless I hesitate to open the book and start learning it. The Brahms first, on the other hand, is in the very comfortable zone of D minor--emerald green--so I learnt that when I was 15 (and thus, as you know from yesterday's comments, could perform it tomorrow without even looking at the score after 30 years).
What I said at the end of the second main paragraph is key: it's not that you learn things best when your brain is developing and growing, but that when you are young, before the analytical way of thinking takes over completely, we have all kinds of signposts--physical, emotional, curious, observational, above all physical (which I call "kinesthetic"--i.e., brain-to-hand coordination), which aid the brain in the learning process of anything. These tend to drop away as we age, and we become more and more dependent on pure analysis, and that can be misleading, or, at the very least, less effective than analysis combined with physical associations. As someone once said, "I wouldn't trust my subconscious around the corner on its own."
The fact that Rachmaninoff's D minor concerto is always in emerald green to me ensures that it always has the right feeling. Without that physical association, I couldn't trust that it would always be right. The physical association is much more reliable than the intellectual one. If a child burns his hand touching the stove, that physical association (hand-to-brain association and memory) is much more reliable than a theoretical injunction not to touch the stove, don't you think?
There is a current vogue for presenting plays and operas in modern dress. While on the surface this sounds like a clever idea, and is often intriguing, it is a purely intellectual, theoretical, one. The divorcing of the ideas and music of a play or opera from the physical setting of their original conception--be it Elizabethan England for Shakespeare, or sixteenth-century Spain or Italy for Verdi, or mid-nineteenth century for Traviata or Boheme--in fact pulls the rug right out from under these works. The removal of the kinesthetic, physical association of the costumes, and settings virtually destroys the foundations of these great works, even though if one closes one's eyes, one can still respond to the sounds or the words.
Irving Berlin wrote 3,000 songs during his career, hundreds of which are all-time classics. Richard Rodgers--first with Lorenz Hart, then with Oscar Hammerstein--did similarly. These came out between the 1920s and 1950s. Both these composers lived 30 years beyond their last successful number, yet, despite various attempts, were unable to ever come up with even one more song. How is this to be explained? The only possible explanation is that the physical associations of the time in which their work was able to come forth--the '20s, '30s, '40s and '50s, stopped cold around 1960. Those physical associations included the Roaring Twenties, the Great Depression, the 2nd World War, and the rebirth of the 1950s, and incorporated such items as Fred Astaire's tails, Ginger Rogers' swishing dresses, tales of the South Pacific, Julie Andrews' homespunness, etc. Without these anchors, it was not possible for these geniuses to produce even one song!
So I definitely believe it's the physical associations and signposts that set the brain off and mark its trajectory on any subject. Still don't know how that guy can calculate 39 X 39 X 39 X 39 in his head in five seconds. The number thirty-nine isn't that sexy. Mind you, I don't like even numbers--much prefer odd ones. 357 is a beautiful number. 246 very mundane and heavy.
But Rachmaninoff's Third Concerto is definitely in emerald green (very sexy key), every bit as much as Gershwin's Rhapsody is in blue (not very blue), and Beethoven's Emperor is in gold (very gold).
Apparently I am not alone. Others see colors where you would not normally expect to. They even have a name for it now: "synesthesia."
But that's not the point I'm trying to make. The point is that the brain is a physical organ and it works properly only in conjunction with physical activity. Playing the piano is a clear case in point: the action of gripping the keys--kneading them, poking them, holding them, stroking them, coaxing them, sometimes whacking them (but always telling them you love them)--is not only pleasurable, it actually stimulates the musical side of the brain and enables it to make all the necessary (and correct) calculations in order to produce a piece of music in actual sound. Those calculations include our memory, emotions, histrionic abilities, projection talents, as well as making the right notes go down when and how they should.
The same can be said of a carpenter, or builder, or anyone else working with their hands and bodies. The brain works in direct proportion to the physical activity of the hands and arms. The builder may not be thinking about the quantum theory, moving on from where Einstein left off, but what he is using his brain for is spot-on, true and indisputably demonstrable. Whereas without any physical involvement, our minds can play tricks on us and not be entirely reliable. For example, if one works late at night, alone, in a darkened house, one can start to hallucinate, or at the very least imagine problems to be greater or lesser than they may in fact be. In the light of day, outside, with the stimulus of physical activity or movement, our perspective is much more reliable. Even just taking a walk will get the brain working better.
I use colors just as an example: colors are a tangible, physical thing (though of course colors are to an extent dependent on light). The colors of musical keys may be a little fanciful (but then, why does the number 39 make that guy on the video feel all warm and fuzzy, and he'll do anything easily and happily for the numbers he likes--it's obviously a personal thing). However, with stage productions it's no longer just fanciful. Traviata has to be basically in midnight blue or it's way off base, Tristan and Isolde misty blue, Aida golden, likewise Meistersinger, Tosca black and scarlet, Butterfly pastel cherry blossom, the Ring murky dark green. There's no question at all about any of that. Traviata is mostly set in the night, in candlelit rooms, in Paris. Tristan is mostly on the sea, in Irish mists. Tosca in dark rooms with blood and satin. Aida with trumpets and processions. The Ring all forest-bound.
But as I say, color is merely an example. The brain (I'm speaking from personal empirical observation as a pianist) really only functions properly in tandem with physical activity and stimuli. It's no more a purely theoretical or intellectual organ than the heart or lungs. Give it the right oxygen and it can do anything. Give it the right emotional associations and it can make calculations that no computer in the world can match. That guy's brain likes the feel and touch of certain numbers, so it's off and running. I like the feel and touch of Chopin, so there's nothing I can't or won't do to play that music. The feel of Bach fugues does not turn me on, thus, while I can learn and play them, my brain pushes them away, and it's a huge effort to get the recalcitrant organ to cooperate.
This is NOT a question of keeping awake, or about getting blood flow to the brain. This is about the "kinesthetic" operation of the brain, i.e., that it doesn't function correctly unless the thinking is tied to real, physical, 3-D anchors--be they colors, physical associations of all kinds, including ones which have been transformed into memories, sets and costumes in a play, keyboard for a pianist, hammer for a builder, molding things with your hands, holding the organ in your hands if you're an anatomist, etc. I don't think the brain can function properly by itself on a purely theoretical level. If divorced from 3-D reality, it just starts to fantasize.
Which is OK too, but it's a different proposition from a well-oiled, thinking brain dealing with issues and questions with a view to finding rational and workable solutions and perspectives.