However I can hear music very clearly in my head. If asked to visualize, say, an apple in my head I really don't see it very vividly at all. It's depressing if I'm being honest.
For sound, I can imagine sound and hear it essentially exactly as if I were to actually hear it, but the only sounds I can imagine are sounds I can make myself. I can't imagine a song per se but I can imagine myself humming it. Same as above, when on the verge of sleep my sound imagination can switch on and I hear music as if I were at a concert hall - dramatically different from my day-to-day experience.
Because of this, I can assure you that there are real differences between people's experiences, despite what others might tell you.
I used to be like that in the past. I would sit in a chair and the music would come. Then I knew I was close to sleeping, and it happened every night when going to bed. When I woke up the final stage of sleeping also had music, then it was suddenly, brutally switched off and I was awake. It felt as real as if it was heard live. The thing is, the music was always something I'd never heard before, and it was huge and with lots of instruments. Classical, mostly. It was very similar to the "music everywhere" experience in the Salaxian ship described in the novel "Dirk Gently's Holistic Detective Agency".
For various reasons I went through a sleep-deprived phase, and after that time I lost the music. No music when going to sleep, and none when waking up. After many years I started to get a different experience, I would dream about music events (watching some band, for example, or some other event), hear nice (non-classical) music, and, if I woke up, trying to find a pen and write down the chords or the music - but it fades so quickly that after writing down the beginning it would all be gone.
The brain is the strangest thing.
If you picture something like a pirate, and someone asked you about the scene, eg; what color are his trousers, what kind of shirt.. You will get a question that you don't instantly know, your mind will quickly 'colour/paint in' so you can answer, but the important part is that you didn't notice that bit was missing before you were asked, which is not now a real picture acts - you would have noticed the pirate had no trouser without needing to be asked about them.
eye-sight itself is an illusion to some degree, eyes don't send images, they send data that is re-assembled into a construct of abstractions, aka you don't see a cup until you know its a cup. there are a lot of optical illusions that exploit this.
What is the color of your underwear?
Perhaps you will remember what color underwear you put on this morning, perhaps you will check, but it would be pretty weird if your underwear's color was constantly on your mind. Nevertheless, I doubt you would argue that your underwear did not have color while you weren't thinking of it.
Now open up an image of a pirate on your screen. Click on the window and drag it down until the bottom half is off the screen. What color are the pirate's trousers? The computer is only displaying a portion of the image, so technically the pirate's trousers don't exist. But nevertheless the data in the image file would suggest that the pirate does in fact have trousers of a certain color, even if that color is just a number.
You are correct that visual memory does not work like a photograph, but why would it? Your eyes don't send photographs via mail to a little post office in your head, your vision is a means of processing the signals of huge numbers of neurons firing together. Visual processing ought to the same circuits in the brain as vision, the fact that it behaves like vision is evidence that those circuits really are in use.
Of course what I imagine is an illusion, no one is proposing that simply by imagining an object it will manifest in reality. The point is that it is exactly the same sort of illusion as the one that my brain makes when I see real things, and thus my perception of my visual thoughts is the same as my perception of the visible world.
And the point is that picturing something to many feels the same as looking at a picture, but in actual fact that feeling is an illusion.
>my perception of my visual thoughts is the same as my perception of the visible world.
If this were true, you would not know when the picture of the pirate was partially off the screen. Or conversely you would know that the mental image of the pirate had no trousers before being asked.
Picture Jack Sparrow (assuming you feel like you have a good memory of pirates of the carribean). In particular, picture his sparrow tatoo. Write down what color it is. Then look online at an image of it [0]. Is the color the one you wrote down that you pictured? Repeat this again for any image you feel like you remember. If your mind were simply making you think that you were picturing things correctly, what you write down should rarely match reality. On the other hand, if you are actually storing visual information, your memory should pretty regularly be correct. Not everyone actually does store data visually, it really could go either way.
With regards to your comment, the instruction was to picture a pirate, not a pirate's shirt. If you look at a photograph of someone, do you become instantly aware of all information contained within it with perfect detail? If so you must be great at where's waldo. For the rest of us, we perceive a gross overview at first and to identify any details we must focus in. But the fact that we don't know where waldo is before we look for him does not mean our brains are retroactively placing him into the picture.
But the idea that when you see a (real) picture, or scene in the real world, you actually see it all - thats an illusion. The mind doesn't work that way. You only see the little bit you're focusing on, but the brain tries to trick you into believing that you see it all. What really happens is that when you want to know about the trousers you focus on the trousers. Until you do that you don't actually know. If someone asks you to describe details about the pirate's clothes you'll first scan every part sequentially, add what you see to a list of answers, and then answer. Things work the same when you imagine a picture (for those who can do that) - you'll know the details only when you focus on each detail, and, as the image wasn't a physical one on the table top the mind fills in as and when it's needed. Just as when you process a physical picture.
A glance at the image would tell you those kinds of things, a 'glance' at a mental image should tell you the same, but it doesn't.
I agree that our experience of sight is an illusion as well, but its demonstrably different to the illusion of our experience of imagined imagery.
But that's beside the point. For me or you to have a mental image of a pirate with no pants on we'll have to create that image in our minds first, with missing pants and all, so how can you compare that with being presented with a picture on a table?
Compare your memory of, say, song lyrics - you might misremember some of the words but that doesn't mean your memory of the lyrics aren't real, you are remembering a real and coherent set of words, not making them up as you go. When you hear that song again and you know what word is coming up next that is not your mind conning you, that is just successful recall. Likewise you probably know the melody of the song; though you might not be able to transcribe it, you would immediately notice if even a single note was off. More impressive, you can probably correctly identify a song you haven't heard in years from a fraction of a second long sample. If you show me some tiny portion of a photograph of something I've seen before, I will similarly be able to identify it instantly.
I used to think that everyone experienced the world the same way as I did. Personally, as a visual person, I found graphs to be the most intuitive way of conveying information. How could anyone not understand a graph? But my brother can't make heads or tails of them. He's an incredibly intelligent person, but he fundamentally does not process and store information visually. I've met many other people who can think in ways I can't, such as people who can think visualize objects in 4 dimensions.
If you want further evidence that thought processing is not constant across different people, consider that it is not even constant over a single lifetime. What language do you process language in? If you learn a second language, most people, myself included, eventually reach a point where you can think in that second language without using your primary language as a mediator. The brain is simultaneously incredibly powerful and incredibly plastic. Entire regions can be repurposed to function in radically different ways. All evidence points to extreme variability in how our individual minds work.
I was born with severe farsightedness and astigmatism(12 dipoters) and it went unoticed for a while, I learned to walk before I got glasses, I think it might be the reason my brain didn't connect the graphic card for thinking, does it make sense?
It would be absurd to conclude that just because a physicist isn't a champion at billiards that he can't think in terms of vectors, or that someone with a speech impediment can't process words clearly in their mind. That someone who can see an image clearly should be able to perfectly reproduce it does not logically follow.
Usually no, but (anecdote); I cannot normally remember my credit card number, dreaming years ago i read the number aloud and when i woke i could remember the numbers that i had recited in the dream, i checked and they were correct... So at least sometimes in dreams the detail is real.
I have a theory that memory recollection is linked to social impulses, that our minds forget things on purpose (without our knowledge lol) as a tool for social integration. I've seen some indirect evidence of this in some sports, where people tend to be just about as good at a sport as their social peers, change social peers and they become better or worse accordingly. -this would have interesting implications for aphantasia treatment.
Try taking something you know and putting it someplace else you know but which is unexpected.
Like your sofa in your supermarket's car park. Or your pet under your desk at work.