Regarding “a human brain can hold enough information to fill 10 libraries”, can we quantify the memory required for a given task?

It is not the exact phrase, but I have heard variations of this claim. I am wondering whether such claim is supported by a study or experiment. I am also curious if there is a way to sort of vaguely quantify memory. In other words, is there a way to know how much memory/resources a type of task occupies? For example, is it possible to know experimentally whether the muscle memory required to play a piano needs more memory/resources than the memory needed to read a piano sheet?

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Depends a lot on information theory factors like efficiency of storage. Chunking may improve efficiency in organic memory, much like digital encoding improves efficiency in physical memory. I wouldn't pit a person against ten libraries filled with terabyte hard drives unless that person could chunk at savant level. Note the implied influence of individual differences here too. Anyway, performance on secondary tasks may serve to operationalize free attentional resources adequately. –  Nick Stauner Feb 5 at 4:17
Define "library" –  rmayer06 Feb 7 at 2:50
And just as a comment- the term "chunking" applies to short-term working memory. Long term memory is a bit fuzzier, relying upon associations within a schema to be able to access. But, long term memory is also mutable, in that it is read and re-written every time it is accessed. So, I think this question cannot be answered given how little we know about how memory works. –  rmayer06 Feb 7 at 2:52
@rmayer06 I know it's vague, but it simply means a large amount of information. Say, at least 400 books? But even so, I don't think it is that important to know what a "library" is for my questions. After all, all I am asking is how someone determined how much the human brain can hold. Of course, the amount must be finite. But the method of approximation that the researchers used is what I am after (if such research did indeed happen) –  user97554 Feb 7 at 15:21
@rmayer06 Also, I have tried looking up chunking but couldn't find a source which claims that it only applies to short term memory. Could you show me where you got that information? –  user97554 Feb 7 at 15:23

First, consider that those questions can potentially be answered only in animals, like mice. There is no way to test such things in humans, because methods like fMRI give resolution of $\approx$1,000,000 neurons. In order to test your hypothesis, you need resolution below the neuronal level, because what your need to see is how the connections (synapses) between neurons are established. Theoretically, you can train mice to run a maze. Then, with a microscope, one can count how many synapses were created. I think, to date, you cannot do this without killing the mice. If so, then you will take other mice and teach them to play piano :) So, the difference between change of connections might be your estimate. But you cannot know whether two tasks are equivalent, so you may end up comparing apples and tomatoes. Overall, the term "memory" is not something that is precisely defined on a biological level, like RAM or hard-drive capacity on a PC. There are prominent hypotheses about how memories are created (connections between neurons), but those are still hypotheses.