When I teach an average 5 year old beginner and compare it to say an average 70 year old, the OVERALL difference I find is negligible.
I can see that they would probably learn easy material at similar rates, but do you find that adults tend to have a lower skill ceiling?
In the same respect I have taught naturally coordinated adults who have never played piano before and they develop very fast, their age has no effect on their acquisition of skills. Perhaps they could have done it faster as a child but who knows? Perhaps they have trained other skills which relate in some way to piano? The fact remains that their ability to learn is still at a very high level even as they age.
The most extreme case of this I have experienced is a lady I taught when I first started teaching piano. She was in her 50s and pretty much devoted her life to her family and children. She did dabble with the piano here and there over the years but never took it serious or had time for lessons. After a couple years study with me she was would have been able to host her own concerts no problems at all. She also took up portrait drawing and then painting while we had piano lessons. She NEVER had done any drawing or painting before but she produced photorealisitc works which stunned her art teacher (and myself!!) who said they couldn't teach her anything at all! She was a real freak of nature with insane artistic capability and age did not slow her one bit.
This is very interesting. I'm growing to realize that the differences in individual abilities and their trajectories throughout one's lifespan can be massive. The examples you mention of adults who have actually been able to . I find that in some ways the way I've learned the piano may not be that different from a child's -- I can often immediately observe and imitate hand movements pretty well for example, and I just hear the differences in sound with different approaches pretty well. I was earlier quite afraid that there would come some day when I would magically lose those abilities, but looking at people who actively maintain such abilities to learn (musicians, researchers, creative professionals, etc.) it seems like although it gets a bit worse, they usually retain those abilities well into their 50s and 60s.
The danger is that you can overstep the mark and spend a lot of time trying to stubbornly improve something because it allows you to "prove" something.
There is a real danger here, but it can also drive one to improve (and I credit overstepping the mark to a lot of my progress). However, I think it's important to isolate key difficulties accurately, and try and work on those over a period of time, while not neglecting developing other skills. For example, you can fantasize about playing the two-handed scales at the end of the first Chopin ballade at tempo, and you can attempt to "solve" them on and off for months, and I have found that sort of thing to be quite useful. However, you are still probably spending at most half an hour a day trying to play those, while the rest of the time is spent tackling a bunch of other skills which eventually feed into this one. So you're not tackling the actual Chopin ballade, but you're attempting individual parts essentially as "exercises".
There are mental skills which are more strongly related to piano playing like being able to see the letters ABCDEFG in your minds eye and being able to skip around it and still be aware where all the letters are in relation to one another helps a great deal with reading calculation. Spatial reasoning tests like seeing a shape and rotating it and being able to visualize what it would look like, or seeing a series of patterns and infering what comes next, these kind of IQ type puzzles have connection to how we visualize shapes at the piano and how they interact with one another.
Yes, I've also had similar observations. I was studying group theory the same time I was learning piano, and I was just thinking -- the musical alphabet is just Z mod 7. Try and get really good at doing arithmetic with those seven letters, counting them forwards and backwards, quickly skipping up or down two notes, etc. and that would be very helpful.
While sight reading, you often have a pattern such as an Alberti bass which repeats, or a section which repeats. Earlier, I used to quickly glance up and down the staff paper trying to see if the notes were really the same or not. Later on, I found that it helps if you can "copy+paste" in your mind's eye. It's much faster if you imagine the shape of the notes, and then superimpose that shape in your mind on the shape of the notes you're comparing it with, which immediately reveals discrepancies. I can certainly see how this kind of thing would be related to spatial reasoning tests.
Mathematics also has a connection to piano of course. I taught one maths teacher and he would show me all sorts of maths ideas connected to music, I remember him showing x vs y notes with a mathematical proof to show how all combinatinos would work together.
The relationship of mathematics with music is something which I've often thought about. They share a superficial similarity, with note values and durations etc., but that is just elementary arithmetic such as fractions. If you can do basic mental calculations and can for example add 1/3+1/4 within a second (which isn't really a hard skill to develop), it helps with learning how to read rhythm faster. However, this is still elementary school math. But at the same time, I've seen that people who are naturally good at mathematics tend to like music more, and you can often quickly get across musical ideas even if they've never heard before. Which leads me to think that there is some transfer between the sort of quick mental manipulations, rotations, visualization, etc. you need to do in mathematics (at a college level, at least), and observing patterns and teasing apart the underlying structure behind a piece of music.
There must be something in the genes of talented musicians, your father probably would be a fast learning pianist just as yourself and maybe even your mother and your grandparents.
There is a certain appreciation of music, though not for the Western classical tradition. I later got to know that there were a few well-regarded musicians (and poets) in my grandfather's generation. My father picked up a couple of instruments on his own for a bit and I think he had a good ear, but he left it to pursue his field.
When I teach students music they really like and are capible to learn in an efficient manner, they learn it many times faster than anything else.
This is one of the things I have thought about in my quest for the fastest way to progress at the piano.

Many teachers are very confident that what they do is nearly ideal for students, yet they disregard situations such as these where the same students progress markedly faster. I find that the same thing happens with other fields. I think these kinds of observations can help one go behind the process, because you wonder that since such a rate of learning is demonstrably possible, why can't you apply it to other things? And from there you can create a kind of bridge to apply that insight into actual teaching or studying. One of those insights for me was the effectiveness of my study normally vs before the exams (which was massively different), so I tried channeling it by telling myself that I needed to get something learned
today. The effectiveness, of course, depends on how much you can actually believe that.
This is diametrically opposing the viewpoint of working countless unknown hours on a single difficult piece until it is completed something that many people attempt to do. My students understand what works are too difficult and ineffient to focus on, this doens't mean they avoid it altogether but they certainly understand how much slower it is for them to obsess over them and they continue building their skills succesfully elsewhere.
Thinking back, I realize that I have never worked countless hours on a single piece at a stretch. I constantly bounced back and forth between levels, and I think the most time I spent on any piece in the past was about one and a half months. (This is about the amount of time I spent on the Fantaisie Impromptu.) So in a sense I may have been inadvertently tackling pieces at my level all along!

Also, I hadn't seriously started learning classical piano until the middle of last year, so I was , and as you know I had to start learning sight reading from scratch (Kravchuk's 354 exercises in C major lol)since last June.
I think the process I used was to attempt to play difficult pieces, and let the problems simmer in the back of my mind by touching upon them and attempting them every so often. After a few months, I would realized that my mind had finally figured out the solutions, and I was able to actually execute what I wanted to much better than before. I've given a number of analogies for this in the past, but this process is something which step-by-step learning simply does not allow to happen, and I think it has been instrumental in my case in driving significant improvement.
The articles you posted are interesting but I feel that we should attempt things for ourselves before theorizing about it. There are already a lot of obstacles in peoples way to improvement.
You may be right. I am concerned because I've realized that my memory for sound doesn't appear to be as strong as it once was. I mean, it's still pretty good, but I can remember songs which I listened to when I was 8 years old, which are just permanently imprinted in memory, and I can hear them in my head about as clearly as a recording. I do remember the newer pieces I listen to, but I need to refresh my memory or else the vividness of the sound tends to dull over time.
If you asked me to feel that way as a teenager or young kid it would be very difficult. But because I have a very rich personal journey with music that no one else has had, this is very precious to me, it is not about other people it is about this mysterious personal journey I am having with music, and how it has given me Life. I am sure many other pianists will understand what I am saying here.
I can relate to this, because playing the piano is something very personal for me as well. I have essentially crafted the journey I've had with the piano so far on my own terms. There was no one asking me to do this -- in fact, most people didn't even have a clue what I was doing. But to start with that seed of an idea, the expressive power of the piano and its ability to convey one's internal musical thoughts and a strong conviction that to do so was possible and that I could eventually learn to produce what was in the mind's ear, and actually largely have it realized, pretty much on my own, is something I will forever be proud of. It often leads me to wonder that given that I have had this kind of success on my own, what would have been the possibilities if I'd started early on? -- would becoming a top-notch musician have been on the cards, which is not a real possibility right now? That aside, I don't regret my experience with the piano at all. People often ask me why I hadn't gotten a teacher from the beginning. Apart from the fact that I didn't have the resources to do so, it is also because I would never have realized the effectiveness of my ideas on self-instruction and would have been left forever wondering if that idea I had back then would have actually worked. That is something very few people get to experience, and I'm quite thankful that I had the space to do that.
It is however quite difficult since the variation in people is immense. What works for one will fail for the other, some need 100 baby steps to get from point A to B, others can do it in one step.
At this point, I really don't think teaching a large group of students is effective and may be completely replaced by a virtual medium such as a video or textbook, but I think you can really try to optimize your teaching in a one-on-one environment. Piano teachers would have to deal with this all the time because every student is different.
I really like this Feynman video on the topic.