When I listen to familiar music, played very softly in a noisy environment, an odd thing seems to happen. Often at first I won’t recognize the music – I can’t pick out the lyric or melody from the background noise.
When I finally do recognize the music (maybe the voice gets louder for a moment, or one of the musicians plays a riff that IDs it), it’s entire nature seems to change. It seems to be louder and clearer, I start hearing individual instruments I didn’t hear at all at first.
My assumption is that I’m NOT actually hearing it better, that I’m inserting parts of the music from my own brain’s recording of it and synching it with those bits that I really DO hear.
It’s also possible that I am actually hearing “better” in that I suddenly know what to listen for, and my filtering of extraneous sound works better. I’m not sure why, but this possibility seems less likely, perhaps because I am struggling and failing to hear elements of the music in the time before I recognize it.
It’s also possible that I might hear elements of the music that aren’t even there. When these loudspeakers are hardly driven at all, they might not actually put out the complete dynamic range that they would if they were driven at a higher level.
If I’m hearing sounds that aren’t actually in the environment, am I technically hallucinating? If the sounds are actually there, but are below the threshhold of my ability to hear, but I do “hear” them because my brain fills in the gaps – is there a term for that?
This is called template matching, and is well known both in psychology, and in electronic signal processing. Most of what you “hear” doesn’t actually consist of going “OK, here’s this sound, what does it sound like?”, but more like “Here’s this sound, does it match this familiar sound? How about this one? Or this one, maybe?” until you get it right. Once you’ve recognized the music, you can put it at the top of your mental list, and very quickly decide “yes, that does match”.
EDIT: This is also why you can always hear your own name spoken in a crowded, noisy room. Your name is a template pretty high on the list.
It actually happens at all levels of sensory perception and processing: much of what we experience of the world is not really there. Instead we are inserting what we expect to be there. At a very basic level that is the reason we experience perceptual illusions as out sensory organs and brains are tricked into applying those expectations falsely. The top-down expectation matching imposed upon the noisy environmental bottom-up inputs, to borrow from the psychologist Stephen Grossberg, the adaptive resonance between them, is what allows us to improve our signal-to-noise ratio.
There aren’t any actual sounds in the room. It is all interpreted vibrations by the receiving person and even then it depends on context and prior experience. The old question “If a tree falls in a forest and there is no one there to here it, does it make a sound?” seems dumb but it is a perfectly valid question and the answer is “no” unless you count the experiences of other animals. There are a bunch of vibrations, light wavelengths, and odors in that forest and we are only used to picking out a few of them and all of that is interpreted by the brain to get the final result. Sound is the interpretation otherwise we might be tuned in strongly to high-pitched noise, very low frequency earth mumbles or something else we aren’t used to thinking about but is still there. No one knows exactly how the human brain works but we do know it is very much unlike a scientific instrument and very different from a traditional computer. It is a pattern matcher first and foremost and that is what it does with sensory perception.
You are listening to the actual sounds in the room as selected and interpreted in the light of your memories (and in the light of certain innate proclivities and biases). Of course, in some circumstances the mind imposes too much structure on input that is, essentially, random, and them we experience what are called hallucinations, but in most circumstances our brains, if they are working normally, are pretty good at avoiding that. Nevertheless, there is no sharp distinction to be drawn between perception and hallucination: it is a matter of degree, of achieving teh right balance between what comes from without and what comes from within.
There is. People make money out of it all the time, and have done for millennia. We call them artists, musicians, movie makers, animators etc. etc. All perception works this way, and anyone who makes money out of manipulating perception is using these facts, even if they are not explicitly aware of them.
You are making some pretty questionable (not unsupportable, but certainly controversial) metaphysical assumptions there. Who says the vibrations are not sounds? Just because the vibrations we detect are selected out of a larger mass, and interpreted, it does not follow that they are not sounds in the first place.
The rest of what you say is more scientifically based, and I have little quarrel with it, except for the implication that there is some sort of “end product” to the process of interpretative perception. Who is going to receive such an end product? The little man who lives inside your head? Rather than there being some sort of “end product” to perception, it is a continuously ongoing process that does not end until you die (while you are asleep, it makes you dream), and it is intimately bound up with the mechanisms of action control at multiple levels.
I wonder if this is related to something else I’ve observed.
We all hear random noises from time to time. If I am in a place with a repeated indistinct noise going on, my brain will try to turn it into music. Sometimes I catch myself ‘listening to the tune’ which in reality turns out to be a truck way out on the Interstate or bees in the flowers. If my sister hears these indistinct noises, her mind makes them out to be speech. She then strains to make out what words ‘they’ are saying.
The difference in the way our brains interpret it is fascinating to me.
i do a visual version of that with phosphemes on my eyelids - i love trying to see images =) I play a game, try to see images and use it as syble like prophecy making =)