But when they took chess boards of randomly placed pieces, they could not remember the placement of pieces any better than a random group of people.
The idea is that through practice, you develop the ability pattern match and chunk together the data into more cohesive blocks, and memory fewer of these blocks.
The rough analogy in software is to take a quick look at some code and recognize the design patterns, and remember the design patterns used rather each individual character.
In fact, words are a form of chunking -- we don't remember hundreds of character sequences, but we remember the words instead.
The difficulty in recalling nonsensical positions is not that it's like "boxing a beginner", it's that the pieces are literally placed in a way that the positions could not have been reached with legal moves.
Analogously, remembering famous quotes or memorable phrases in a certain language is quite easy. If instead, you had to memorize a string of randomly placed words that did not follow established rules of grammar or sentence structure, it'd be a much harder task.
Chunking is context and experience dependent.
I have 20 years experience as a glassblower, and the apparent duration of the most intense parts has mentally expanded for me over time. Guitar playing is similar - my awareness while under pressure for improvisation or a slick solo has slowly changed over the years. The intensity of opening a wine glass foot is about the same as playing a quick improvised jazz solo. If you asked a musician how a performance went, they could probably tell you how it fell playing each line. Same with a glass collaboration – I can usually recall how making a piece went, but in a setting like a collaboration or competition, I would remember every part of making a 2 1/2 minute piece as if it was a 15 minute story.
When you start out making cups, the process can quickly go wrong in a jumble when it is time to open the rim. The next time, you remember to avoid that mistake… but might make a different one. Or maybe make the same one again. Each time it’s 10 or 20 minutes until you can be at that point again... it reminds me of 8 bit games where you have to go through a level repeatedly to get to a difficult jump, and keep trying til you make it. Eventually, you start finishing the process, and after many repetitions can do it without thinking. After even longer you learn every microsecond of the process - with glass, the feel of the hot bubble folding over and turning from a sphere to a flat disc in about 800 milliseconds, as you spin it in the flame. That’s the part that expands mentally for me - the control during that time. One learns to not fail to pay close attention at that time.
While these moments still feel like they are over in an instant, over time, my ability to make good decisions repeatedly while taking it in stride has increased. I’d sum it up as my level of overwhelmedness has gone down.
It’s as if time is expanded, though it all still happens very quickly. Due to all the practice, my awareness stays active instead of being overwhelmed. This phenomenon could also show up in other activities like sports.
Your question comes down to basically nature versus nurture, though. Do some people have innate talent, or does it come from training? It seems like the answer is both, of course. My analysis is that some people are better at releasing their minds to accept learning things. Then, it’s a matter of practice and experience. Anything eventually becomes commonplace.
For example, if you start off learning a language, there are all kinds of tiny details to pronunciation that you don't even recognize and could never recall afterwards. If you try to repeat what someone's said, you might miss a lot of those details.
But if you've become fluent at a native (or near-native) level, you've trained your brain to subconsciously recognize and focus on all of those details and can recite something that someone's said perfectly.
Similarly with basketball or any other highly curated group of individuals performing a skill.