Do you know how to focus and defocus?
You can notice the level of your ability yourself. It becomes clear when someone is not able to focus and defocus when someone studies a book from page 1 up to page last, and never uses the index. I have met people who studied on university level and did it that way: page 1, page 2, up to page last. They experience trouble in exams to proof that they understand what they studied.
In other circumstances it is not so clear. You might try to look at a larger painting or photograph, from one meter or three feet distance. Are you able to look globally, then decide to look into details? Some scan the photograph from top left to bottom right or vice versa. But when you ask them to see the whole picture at once, they cannot.
These people have difficulty in a museum with all those pieces. How do they index all these items for themselves? The problem of being overloaded becomes apparent. They probably overload quickly.
When you are able to globally categorize and dive into details you can postpone being overloaded. Your brain knows where to place things, and keep the overview on things. This makes it manageable.
For others, it might not be easy to experience what it is like, not being able to focus or defocus. They might get the idea by imagining being in a museum where all things are messed up. Try to figure out for yourself how you would enjoy such a museum. Chances are high at one point you do not know heads and tails any longer. How do you make sense of all those pieces?
Being able to focus and defocus at first may seem trivial for some, but it is a quality you need in life.