What is the aural equivalent of colour blindness?

[cloughie]

Back on topic, well close, I think the term tone-deaf is mis-used. I know of people who find difficulty singing anywhere near in tune but when listening to music will analyse the sound very critically - maybe ton-dumb would be more appropriate in this situation.

[Pabmusic]

...Without sight someone like the Guardian example or Dawkins' bat rely only on sound so I can't see how the echolocation process can find the "colour" or even apply a textural equivalent in sound, it's a property that does not belong in the sound world. There is no harm in a bat applying the label "colour" to some property of an object but it is not the same thing as light...

Understandable, of course, until you realise that the labels we use for colour - red, blue, yellow - are not qualities of specific wavelengths of light and cannot be tied exclusively to the electro-magnetic spectrum. They are constructs of the brain for use in modelling the virtual world that is actually what we see. (This is all very counter-intuitive.) They help us make sense of the light we see. That being so, those qualia (labels) could just as easily be applied to other qualities of our virtual world, such as touch or echolocation. So that a person who has never seen anything may nevertheless construct a virtual model of reality using qualia that (if only we could experience them) are 'red' or 'blue', because they help make sense of his or her virtual world.

It's a lot easier to imagine this happening in a world where evolution has produced creatures attuned to it - which is why bats or whales are good examples. Single examples, such as the chap in the Guardian, don't represent an evolutionary trend - he has adapted remarkably by using different senses, but that's not evolutionary change. Our sensitivity to colour is a result of evolution, however. Presumably colour definition was important to our ancestors (all primates have good colour recognition - useful perhaps for creatures that lived in the low light levels of forests and ate plenty of fruit).

[Nevalti]

I suspect that part of this apparent variability in the ability to hear small differences in sound stimuli is down to the individual.

Yes, I am sure that is true. We have, in another thread, identified a massive difference between what I can hear and what Mr GongGong can hear. It is reasonable to assume that less significant hearing differences also exist

The parallel with colour blindness though is inverted; the sight defect is rare whereas the rarity in HiFi enthusiasts seems to be an enhanced sensitivity, not a defect.

Perhaps it is not simply an enhanced element, perhaps some of us completely miss aspects of the music that others hear. For example - I can not get much pleasure from music played on a 'tranny' but some people spend their whole day with 'awful' (to me) music blaring out. They must be getting some pleasure from it that I don't, so perhaps I am the one with a 'defect'. The enhanced sensitivity, that some seem to have, could be a natural compensation rather like (simplistically) a retina has a mix of rods and cones. If you have fewer rods, you have more cones and visa versa. The result is that one aspect of your sight is enhanced and another aspect is impaired. Assuming, for the moment, that the same sort of differences exists with hearing, it could be a brain, processing function or a bio-mechanical difference or a mixture of the two.

[Gordon]

Understandable, of course, until you realise that the labels we use for colour - red, blue, yellow - are not qualities of specific wavelengths of light and cannot be tied exclusively to the electro-magnetic spectrum. They are constructs of the brain for use in modelling the virtual world that is actually what we see. (This is all very counter-intuitive.) They help us make sense of the light we see. That being so, those qualia (labels) could just as easily be applied to other qualities of our virtual world, such as touch or echolocation. So that a person who has never seen anything may nevertheless construct a virtual model of reality using qualia that (if only we could experience them) are 'red' or 'blue', because they help make sense of his or her virtual world.

Isn't that what I said above? Or am I being slow?

It's a lot easier to imagine this happening in a world where evolution has produced creatures attuned to it - which is why bats or whales are good examples. Single examples, such as the chap in the Guardian, don't represent an evolutionary trend - he has adapted remarkably by using different senses, but that's not evolutionary change. Our sensitivity to colour is a result of evolution, however. Presumably colour definition was important to our ancestors (all primates have good colour recognition - useful perhaps for creatures that lived in the low light levels of forests and ate plenty of fruit).

Agreed, but I'm nor sure about the low light bit - human vision degrades to monochrome in low light. Once creatures became sensitive to light in the first place [plants are too] then colour clearly had an evolutionary benefit and that is very old. Apart from seeing your enemies, environmental hazards etc or your food supply, perhaps colour added a valuable refinement. However, when did the sensation become not only a practical advantage but also an aesthetic phenomenon? What evolutionary value does an aesthetic sense have? Reaches for Dawkins, he must have something to say about it.

Coming back to sound we can ask a similar question; a keen auditory sense is valuable for survival, both in terms of low levels of sound - hearing a threat or food on the hoof at a distance, perhaps unseen - but also the analysis of it to extract valuable additional information about the environment. The physiology of the ear is strange, being made of a bank of resonators the excitation of which has a time/frequency characteristic leading to a similar sort of effect to the blind spot we all have. Whatever processing the brain does it is of the sensory input from these resonators which have limited ability. Excite the ear with a sound and it becomes unable to hear closely related sound that accompanies the first if it is at a lower level - the known masking phenomenon. What was the evolutionary value of that? Loud sound is more important than soft when danger threatens?

Interesting that we have two of most things including eyes and ears; without two of those our spatial sense would be degraded. The spacing and placement of our eyes allows 3D/binocular vision [some animals, fish and birds don't have this placement of course] but our ears are separated.

[Pabmusic]

Isn't that what I said above? Or am I being slow?...

Or it might be me.

Agreed, but I'm nor sure about the low light bit - human vision degrades to monochrome in low light. Once creatures became sensitive to light in the first place [plants are too] then colour clearly had an evolutionary benefit and that is very old. Apart from seeing your enemies, environmental hazards etc or your food supply, perhaps colour added a valuable refinement. However, when did the sensation become not only a practical advantage but also an aesthetic phenomenon? What evolutionary value does an aesthetic sense have? Reaches for Dawkins, he must have something to say about it...

He does. What I was getting at (without wanting to enter 'lecture mode' for something that's not quite on topic) was that, in general fruits are quite highly coloured in a way that contrasts with the green of vegetation. One reason this probably came about was through the evolution of colour-sightedness. There is for most fruits an advantage in being eaten by an animal, as it spreads the seeds around. At the same time, there is an advantage to primates in recognising the (bright) colours of fruits among the green. There may then have been what Dawkins calls an 'arms race' where prey and predator sort of 'outdo' each other (except that in all this, nothing is actually thinking this through, of course) and natural selection happens reasonably quickly. We rely mainly on our sight, somewhat less on our hearing and less still on our sense of smell (other animals differ in what is important) and our eyes are some of the best there are - particularly in their sensitivity to colour. A front-runner for the reason why is life in the forest, where sunlight levels are low and the ability to distinguish subtleties of colour may be more important.

Much too simplistic of course, but you see what I was getting at?

Interesting that we have two of most things including eyes and ears; without two of those our spatial sense would be degraded. The spacing and placement of our eyes allows 3D/binocular vision [some animals, fish and birds don't have this placement of course] but our ears are separated.

And some creatures that rely very heavily on hearing (owls, say) have their ears set asymmetrically, which allows very precise direction-finding indeed.

[umslopogaas]

#12 antongould, that Flanders and Swann song is called 'Slow Train'. I have it on the LP 'At the drop of another hat'. It isnt on my CD 'At the drop of a hat', but it must be out there somewhere.

Marvellous pair of comics. I'm particularly fond of 'Madeira M'Dear': " ... now if it were gin you'd be wrong to say yes, the evil gin does would be hard to assess; besides, its inclined to affect me prowess, so have some madeira m'dear! ..."

[MarkG]

There may be an anatomical explanation...

http://www.nature.com/news/2006/060925/full/news060925-4.html

[OldTechie]

There may be an anatomical explanation...

http://www.nature.com/news/2006/0609...s060925-4.html

Very interesting. My father was a violinist (Hallé/BBC Northern) and was very critical about pitch issues. That meant he could tell whether music on the radio was live, off tape (all BBC tape recorders had flutter he could hear) or off disc (virtually all vinyl records go up and down in pitch once per revolution due to not being quite flat, and maybe not having the hole in the middle).

However, he could not sing in tune. I seem to have inherited the some of the same issues. In particular, after you have your father pointing out the record going up and down in pitch every time there is one on the radio you learn to notice it. I never had the sensitivity to tape flutter (he could not explain what he was hearing, but we went to buy a tape recorder and he instantly rejected a Ferrograph and a Revox, and chose a Simon SP5 which turned out to have much lower flutter than the others.)

So now, if I sing I can instantly hear that I am out of tune, and which way I am wrong. But by the time I have hit the note I wanted I am three bars behind. Result, I don't even hum to myself (or at least not loud enough that I can hear it.) Maybe some of this really is inherited rather than learnt.

[Pabmusic]

There may be an anatomical explanation...

http://www.nature.com/news/2006/0609...s060925-4.html

Very interesting. It is very likely that much of our reason for being adept with music will be physical - genetic, possibly.

[Nevalti]

There may be an anatomical explanation...

http://www.nature.com/news/2006/0609...s060925-4.html

Thank you. That is virtually an answer to my original question. It may also be part of an answer into why some of us are 'fooled' by binaural recordings and some of us are not. So, its not the 'grey matter' that counts but the 'white matter'.

My experience is very similar to OldTechie and his father. I didn't realise that some people couldn't tell if it was tape, LP or live. It usually seemed glaringly obvious to me. These days, with good digital recordings, it is rather more difficult but I can usually tell if it is live or recorded by the absence of low level information which has been discarded as 'noise' during the recording process. On DAB transmissions they throw out a vast amount more so that it doesn't sound live even when it is.

As for singing - I can't quite make a complete octave these days so my repertoire is severely limited but I can hit the right notes within my limited range. Rather oddly, I often have difficulty joining in with other singers on the right note but when I see the oboist ready to play the tuning 'A' at a concert, I sometimes hum that note before he plays it. I am often spot on and usually within a semi-tone.

[ferneyhoughgeliebte]

Rather oddly, I often have difficulty joining in with other singers on the right note but when I see the oboist ready to play the tuning 'A' at a concert, I sometimes hum that note before he plays it. I am often spot on and usually within a semi-tone.

Oh, that sounds familiar, Nevalti - I can usually "get" the first note of a work I know well, too. But not if I think about it, first - anyone asking me to whistle/sing an A could end up with any note between F# & C. (I tell them I was using Baroque tuning. If pushed, I'll add "as used in Venice in about 1670: that usually dissuades further interrogation. )