zdenek@heathcliff.columbia.edu (Zdenek Radouch) (11/14/86)
In article <212@mind.UUCP> harnad@mind.UUCP (Stevan Harnad) writes: >> [me] >> Human ear can detect frequencies approximately from 20Hz to 20kHz. >> There is INFINITE number of frequencies (or pitches) in this range. >> The resolution of the ear is not infinite but certainly about two orders >> of magnitude higher than resolution necessary to identify notes in any >> musical system. A person identifying the pitch is basically determining >> if an unknown frequency Fx is from interval <Fmin,Fmax>. It's perfectly >> clear that the ability to do that will depend on the size [o]f the interval >> i.e., on ratio Fmax/Fmin. > >The trouble is that your considerations conflate (1) detection, >(2) discrimination ("resolution"?) and (3) identification. The psychophysics >of each of these is different.... I don't think I am conflating them. I mentioned the range of frequencies and I said "detect" because I wanted to stress that this range has nothing to do with resolution or identification. I further specified that the resolution of the ear is much higher than what's necessary for the absolute identification in question. > ....I should >also add that, because of physics (the "overtone" series, or upper >harmonics of any raw fundamental pitch) as well as physiology (of the >cochlea and the auditory representation), the octave has a privileged >status in perception so we should probably only be considering >sub-octave subintervals in calculating our resolving capacity, relative >or absolute. I agree that the octave has a very special place in intervals because by definition it's the ratio of smallest integer frequencies. I don't see what does that have to do with cochlea. And I definitely disagree with any notion to limit the interval to <2, especially in the case of absolute identification. Don't forget that we don't understand the actual mechanism of the identification. >> As a result of my experience in music and acoustics I can tell you the >> frequency of a tone with approximately octave error i.e., factor of 2. >> This is a result of an exposure to music, not result of any training. Note >> that I don't satisfy your definition of having absolute pitch. >> >> An individual with absolute pitch can identify interval of 1.06. >> Since there is nothing absolute or natural in the concept of measuring time >> and thus frequencies, this individual MUST HAVE GONE through some training, >> or at least he must have been exposed to the same thing I was. >I can't follow you here. What is "octave error".... You present me with a tone Fx and I'll tell you it's frequency is Fn. I should be correct within an octave i.e., Fx is from <Fn/2^1/2,Fn*2^1/2>. >Also, what is the difference between exposure to music and training? I have been playing music for about 20 years, but I haven't practice any tone identification. There's a difference between the two. There can be an individual with absolute pitch but no knowledge about any concept in music. > ...And which of >my definitions of AP do you fail to satisfy? Since I can only say "it's between a1 and a2" as opposed to "it's c2" I don't classify as a person with absolute pitch. > ....Finally, I can't follow at all the part about the >unnaturalness of frequencies. Slowly here. I said "the concept of measuring time and thus frequencies" (frequency = 1/time). There is nothing natural about second as a time unit. It could as well be twice as long. It's man made. Therefore in order to be able to say "this frequency is F" either somebody presents you with the same frequency before, or in a more sophisticated case with some other frequency. In both cases you have to learn something first. That's the catch in the discussion of innate/acquired absolute pitch. EVEN IF YOU INHERITED THE ABSOLUTE PITCH (and I doubt it) YOU CAN DEMONSTRATE IT ONLY AND ONLY AFTER SOME TRAINING (someone has to tell you what it is, you hear). >Would you say the same of colors (i.e.,that they must have been trained)? Of course. You have to learn that a particular color is red as opposed to green. The only way to describe color in absolute way is by its frequency or more commonly and less precisely by its "name". But the only relation between green color and the word green is that we AGREE to associate them. Someone else could as well call it yellow. Also, we AGREE on the wavelength only because we use same (man made) length unit. So we say its wavelength is 550 nm, but if we shrink the meter it could be 730 nm. The sensorineural effects are the same, the sensation of the color is the same, but unless you train the individuals first, one is going to call it green the other yellow. Same applies for the units used. There is no difference in acoustics. > ....It seems to me it's an empirical >question which instances of categorical perception arise from >training, which from exposure, which innately, and which not at all. > I'd say it's empirical only as long as we don't understand the mechanism behind it. >According to the theory of categorical perception, by the way, >"quantization" consists of the "bounding" of subregions of a continuum >by compression and/or expansion of the Weber function. > According to my dictionary, by the way, "quantize" is to subdivide into small but measurable increments. This happens to agree with the definition used in physics... >> > ....As long as someone is not entirely >> >deaf, some frequency discrimination must be present. >> Why? Seems to me that it'll depend on the actual hearing mechanism. Also, >> considering that most of the theories prefer acquisition in frequency >> domain, I would tend to disagree with your statement. >I can't follow this either. Hearing may vary in acuity for frequency >discrimination, amplitude discrimination, temporal resolution, and >verious aspects of timbre and acoustic pattern. I am just suggesting >that most people who call themselves (or are called) "tone deaf" >probably retain considerable frequency discriminative ability, and >have probably been called tone deaf either because they cannot carry or >or identify or recognize a tune, or perhaps they have demonstrated >diminished frequency discrimination. Production is clearly a different >problem from discrimination. Now I understand what you meant and I agree. My objection was to the implication: not deaf -> able to discriminate frequencies. The preferred model of the sound acquisition (as in signal theory) is in the frequency domain as opposed to time domain. You can model the cochlea with the hair cells as a large array of sound detectors or transducers that convert mechanical vibrations into signals. The signals are then processed in the auditory cortex. But the detectors are amplitude detectors with limited frequency range of operation. That means a detector can only tell you what's the amplitude of a particular frequency or more precisely of a narrow band. The frequency discrimination is then possible because: 1. There are many of these detectors with frequencies varying over the audible range. 2. The composite signals from the detectors are precessed in a very sophisticated way. Given this model, if the cochlea is damaged (as a result of an infection) and only a little part stays alive, you are left with a couple of amplitude detectors and no frequency discimination. You could still hear some "noise". I would also speculate that if something bad is done to the auditory cortex, you can't predict how the sound will be interpreted. zdenek zdenek@cs.columbia.edu or ...!seismo!columbia!cs!zdenek