In his marvelous book Incognito: The Secret Lives of the Brain, David Eagleman two related learning models. The first involves the determination of the sex of day-old chickens.
It was based on very subtle visual cues, but the professional [chicken] sexers could not report what those cues were. Instead, they would look at the chick’s rear (where the vent is) and simply seem to know the correct bin to throw it in.
And this is how the professionals taught the student sexers. The master would stand over the apprentice and watch. The students would pick up a chick, examine its rear, and toss it into one bin or the other. The master would give feedback: yes or no. After weeks on end of this activity, the student’s brain was trained up to masterful–albeit unconscious–levels.
Meanwhile, a similar story was unfolding oceans away. During World War II, under constant threat bombings, the British had great need to distinguish incoming aircraft quickly and accurately. Which aircraft were British planes coming home and which were German planes coming to bomb? Several airplane enthusiasts had proved to be excellent “spotters,” so the military eagerly employed their services. […]
With a little ingenuity, the British finally figured out how to successfully train new spotters: by trial-and-error feedback. A novice would hazard a guess and the expert would say yes or no. Eventually the novices became, like their mentors, vessels of the mysterious, ineffable expertise.
Incognito (Eagleman), page 58
There is a lot to be said for rethinking the conscious approach to learning that defines the way we teach. I especially think ear training would benefit from this approach. Imagine hearing a chord and being asked, major or minor? Within a few hundred repetitions, I think most people would be able to differentiate and move on, confidently recognizing those triads. Build specific skills in series.
Play a chord progression, stop on a chord and ask, IV or V?
7(9) chord or 7(flat 9)?
Gershwin and Gershwin or Rodgers and Hart?
We are asked so often to learn this kind of musical knowledge intellectually – think it through, learn the properties, recognize it on paper. But we’d probably be better off if we built them unconsciously, using our brain’s remarkable ability to learn.
(This is also the secret to my sons’ mastery of Demon levels in the video game Geometry Dash – blind repetition encodes the knowledge they need to complete a level apparently without conscious effort.)