Recognising tunes and shapes

jhnbrbr

New member
Hi all! I just wanted to share an interesting thought which occurred to me some time back. At the time I had a girlfriend who was doing an MSc degree which involved writing computer software to recognise geometrical shapes. I was still a church organist at the time, and one day, while I was staring at the hymn book during a particularly boring sermon, the thought went through my head that what goes on in our brains when we recognise a tune must be quite similar to what goes on when we recognise a geometrical shape. When I thought about it some more, I realised that there are some quite amazing similarities. For example, if I drew the outline of a human body on a piece of paper (even if i drew it badly)you would instantly recognise it. If I then rotated it though say 30 degrees, you would see all the lines had moved, but you would still recognise it for what it was. I could continue rotating it , and you would still identify it as the same shape, but when I had rotated it through a full 360 degrees, you would then register that there was a stronger relationship with the view you saw first.

Now, to take the musical equivalent. If I played "Oh Danny Boy" on the piano (and even if I played it badly) you would be able to recognise the tune. If I then transposed it up a semitone, you would hear completely different notes, but you would still identify it as the same tune. You would still identify it correctly if I transposed it to other keys, but when I had tranposed it a full octave, the tune would have a closer relationship to what you heard first.

I haven't got a clue what all this tells us, or what use it is, but I still find it a fascinating thought.
 

sunwaiter

New member
thanks for posting this thought. it is true that some processes are hard to define. this could lead to a reflection on the concept of beauty, because it makes us reflect on the concept of form, and as musicians, form is important, even if sound is much harder to seize than solids, liquids, gas or light.
 

jhnbrbr

New member
It's interesting you mention beauty, because I did wonder if it might be possible to demonstrate how a pleasing shape corresponds to a pleasing musical phrase, but I didn't get anywhere much. Perhaps that was too simple-minded an approach.
 

smithson

Banned
All of Nirvana's stuff is tuned down a HALF-STEP...that means your guitar will be tuned like this...
Eb Ab Db Gb Bb Eb

and yes that song is in drop D so...

Db Ab Db Gb Bb Eb


------------------------


 
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dll927

New member
A while back I read that Eleanor Roosevelt (of happy fame) was so tone-deaf that at the end of a piece she had to have somebody tell her it was over to know when to applaud. Apparently, she never caught on to just watching the rest of the crowd. Or maybe she just didn't go to concerts. She was too busy being Eleanor Roosevelt.

Yes, our powers of recognition could probably bear some explanation, but on the other hand, dogs and cats do the same thing with their masters. And I used to swear that my late lamented kitty-kat had something resembling memory.

As for transposing, that's just a mechanical adjustment. I'm organist at my Elks lodge, and I do it all the time, depending on what I'm going to play next. I've played some hymns in keys that never showed up in hymn books.
 

jhnbrbr

New member
Thank you both for your comments. Yes, I agree there's nothing particularly mysterious about transposition itself, but what goes on inside the listener's brain is perhaps more of a mystery than what goes on in the performer's brain. I just find the similarities between tune recognition and shape recognition really fascinating, though I probably didn't explain it very well. To try to put it in a nutshell:

GEOMETRY <-> MUSIC
shape <-> tune
angle <-> pitch
rotate <-> transpose
360 degrees<-> one octave

It's not an exact parallel, because when you have rotated a shape through 360 degrees you are back exactly where you started. When you have transposed a tune by one octave it is not exactly the same, but nevertheless there is a subjective feeling of having "turned full circle". I wonder if this analogy is one reason why music has such a big effect on us. Our brains have developed to be very good at recognising shapes for survival purposes, and because tunes behave like shapes in some respects, the same mental processes can be brought to bear upon them.
 
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Soubasse

New member
This is an interesting process, especially the way you've compared it to the recognition of shapes. I've done a little bit of (not all that extensive) personal research on the way the brain reacts to various frequencies (largely in relation to the "entrainment" as it's called, of neural networks), and I recall a New Scientist article that made mention of the fact that birds will not recognise one of their own calls if it's been transposed. Do they have perfect pitch? or simply an altogether different way of processing what they see/hear? Fascinating thing the brain
 

jhnbrbr

New member
That fact about birds is quite surprising. It probably explains why they've never sued Olivier Messaen for plagiarism! I'd love to know whether they have an equivalent limitation with shapes. If a bird sees a dead bird in a horizontal position, can it still identify it as a bird? You're right, the brain is fascinating, and this subject area is so vast and challenging it's easy feel totally overwhelmed by it. I have a vague notion of what neural networks do, but it's hard to make the jump from connections being made between neurons to what we experience subjectively as conscious human beings. I imagine it's true to say that things like consciouness and perception are one of the biggest frontiers of knowledge at the moment. It probably doesn't help that our culture is so compartmentalised - on the one hand you have the "art" of music and on the other the "science" of sound - and they don't even talk the same language, eg one says pitch and the other says frequency. Generally speaking, musicians talk about music as if it was a self-contained set of rules, without ever referring to the underlying physical phenomena. For example, how many musicians could explain the physical basis of consonant and dissonant harmonies? But what goes on inside the mind is even more difficult to comprehend. (When I think about vision I inevitably get drawn into a childish interpretation where wires from the eyes go back into the brain and are fed into a tiny television screen, where a tiny little man sits all day looking at the pictures!) But it is in the mind where the music actually happens . The old saying "beauty is in the eye of the beholder" should really say "..in the mind of the beholder" and the same must be true for music.
 
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