Here is a different story that I didn't tell this morning. It is about Ty Cobb, the famous baseball player commenting on Babe Ruth. I can't recall the precise reference for you but I believe I read this in a biography about Cobb. The story is that Ruth learned his prodigious swing by self-teaching. He wasn't coached. Had he been coached, he almost certainly would have been told to shorten the swing, because that was the style of the times - smallball. But Ruth came up as a pitcher, not as an outfielder. The tradition was not to coach pitchers on their hitting. So Ruth could as he wanted there. He became an expert at something entirely new in a sport that wasn't so new. He made the home run the centerpiece of the game.
There is a moral to the story about deliberate practice qua self-teaching versus deliberate practice at the hands of a well known coach. Many (though not all) well known coaches tend to teach orthodoxy in the field of endeavor. Self-teaching, in contrast, is apt to produce an unorthodox approach. Orthodoxy may be what you are after with expertise. But in some cases the unorthodox can trump. When some people do become expert by self-teaching and others via professional coaching, it is interesting to ask whether their approach converge or not. When not, one might not consider the other an expert and might be right about it, and vice versa. But it is not a priori obvious which one has more of a leg to stand on.
One last point here that circles back to an early theme in the course. The economics profession has an orthodoxy to it and behavioral econ is not yet part of that orthodoxy. But the profession as a whole was shaken severely by the financial crisis. So from my point of view - I'd like to see both tracks proceed for a while as separate ways of developing expertise and not yet insist that they converge. I don't think we're ready for that.