There’s a thing — and I’m sure someone else has written about it with more scientific rigor than I am about to — where your brain is unable to re-solve a problem that was previously solved correctly because it is focused on a problem that has yet to be solved.
The easiest example of this is, like, “why you can’t multiply three-digit numbers in your head while driving through Chicago at rush hour,” and I am fairly sure I stole that example from Daniel Kahneman’s Thinking Fast and Slow — in fact, the actual quote is “You could not compute the product of 17 × 24 while making a left turn into dense traffic, and you certainly should not try.”
Just so we’re clear, the problem that you’ve previously solved correctly (in Kahneman’s example) is basic arithmetic, not the subproblem of “17 x 24.” The problem you have yet to solve is “making a left turn into dense traffic,” and the problem of solving this problem overloads your brain and makes it impossible to do something you’ve already done correctly many times over but is very easy to do incorrectly if you aren’t giving it your full attention.
Which brings me to the trouble with double expositions.
If you didn’t watch the video — and I don’t blame you — here’s what happened.
I played the exposition of the third movement of Mozart K332 fairly accurately, with one noticeable error.
I repeated the exposition (that’s what “double exposition” means, very common in the classical era) and the piece fell apart a few measures before the error because I was focused not on what I was playing at the moment, but on how I would solve the problem that was coming up.
This meant that I was unable to re-solve the problems I had already solved, because I wasn’t actively thinking about solving them. If the music is easy enough and/or you’ve solved the problems enough times, your brain can autopilot you through. In this case, I had not played that section of music accurately enough times to execute it without active thought, and so — well, you either watched the video or you didn’t, so you might have seen it for yourself.
Want to watch me do it again, with the double exposition in the first movement of Walter Saul’s Sonata #3 for Piano?
There are many more unsolved problems in this piece, mostly because I’ve only been working on it for about two weeks — which means there are many more opportunities for me to overload my brain by thinking about the wrong problem at the wrong time.
I’ll end this short post (I promised I’d start making ‘em shorter and sweeter, after all) by sharing what I can do at the piano if I remain focused on sequential problem-solving the entire way through. ❤️