clarification, contrast perception

[From Rick Marken (931008.1530)]

Bruce Nevin (Fri 93108 15:55:48 EDT) --

I should make clear that in my view identifying a phoneme as a particular
phonetic output is an error, much as it would be an error to say that the
category perception "dog" was nothing more than the particular
perceptions that trigger a dog detector ECS. A given phoneme can have
rather different phonetic alternant forms, and some alternant of one
phoneme may be phonetically indistinguishable from an alternant of a
second phoneme, what is called phonemic overlapping.

It IS an error to identify a phomeme as a particular output (which I
read as "output of a perceptual function") when you are referring to
OTHER perceptual aspects of phonemes -- like the sensations that make
them up, including how it feels to say them, the sound sensations and
transitions involved. We can pay attention to all these aspects of
the phoneme but we can also pay attention to the phoneme itself or to
the word of which it is a component (so that the phoneme perceptions
are no longer evident) or to the inflection of the word, or the
meaning evoked. PCT identifies all these perceptions (that can become
objects of awareness) as perceptual signals -- the outputs of
perceptual functions. But this is THEORY.

Your claim above, that "identifying a phoneme as a particular phonetic
output is an error" can be taken as a claim that the PCT model is
in error (specifically, the perceptual function part of the model)
That's fine -- but as it sits the claim is not very convincing because
it's just a claim -- something you prefer to think. I prefer to think
otherwise, mainly because the PCT model (as it is currently architected)
works -- and it controls some pretty interesting perceptions when these
perceptions are represented as scaler outputs of perceptual functions.
If you have an alternative model architecture for the control of
phonemic perceptions then give us a look at it.

On the other hand, what you might mean by "I should make clear that in
my view identifying a phoneme as a particular phonetic output is an
error" is that phonemes are not perceptions at all; that only the sound
variants that are identified as the same phoneme are perceptions (a
strange proposition) or, better, that there is some other aspect of
words, like "contrasts" that are the real perceptions controlled in
speech. That's a reasonable hypothesis -- I don't care if there are
phonemes or not. But the pair test is evidence that sound variants
(b vs p after s) can result in perceptions that are treated as
identical. In experience (and in theory) I would be inclined to
assume that spin and sbin result in just about the same perceptual
signal at SOME level of the nervous system, even if they do (and
they do) produce other perceptions as well.

Maybe what you are saying is that what we perceive are not phonemes
but "contrasts". Is that it? If so, I could buy it as long as a
contrast is a perceivable aspect of each INDIVIDUAL word.

Could it work like this:

word
sound/ ----> contrast detector -----> c.x
feel

where c.x is the perceptual signal that represent the degree to
which contrast x is in the word sound/feel input. There would
be a bank of contrast detectors in the brain, each looking at the
same word sound/feel inputs and firing in proportion to the degree
to which each contrast is present in input. Does that seem reasonable?
It does to me.

Best

Rick

It IS an error to identify a phomeme as a particular output (which I
read as "output of a perceptual function") when you are referring to
OTHER perceptual aspects of phonemes -- like the sensations that make
them up, including how it feels to say them, the sound sensations and
transitions involved. We can pay attention to all these aspects of
the phoneme but we can also pay attention to the phoneme itself ...

Your claim above, that "identifying a phoneme as a particular phonetic
output is an error" can be taken as a claim that the PCT model is
in error (specifically, the perceptual function part of the model)

I don't think you get what Bruce is trying to say. If I read him right,
one circumstance he is trying to cover is that the SAME phonetic signal
is perceived as a DIFFERENT phoneme in different situation or verbal
contexts. That in no way casts aspersions on the correctness of PCT.
But it does justify the statement you quote from Bruce.

On the other hand, what you might mean by "I should make clear that in
my view identifying a phoneme as a particular phonetic output is an
error" is that phonemes are not perceptions at all; that only the sound
variants that are identified as the same phoneme are perceptions (a
strange proposition) or, better, that there is some other aspect of
words, like "contrasts" that are the real perceptions controlled in
speech.

It's hard to see why you have to deny Bruce the luxury you retain for
yourself, of being able to perceive the phonetics at the same time as
the phonemics. Anyway, he's more trained than you at making these
multiple levels of perception conscious, so he knows very well what it
is like. Most people can't do it, and hear all the various phonetic
instantiations of a phoneme (often including the null instantiation)
as identical. I haven't seen any suggestion that phonemes aren't
perceptions at all; quite the contrary. The claims centre on the idea
that phonemes are perceptions very easily made conscious, and that they are
at the category level, where differences in the lower-level perceptions
don't matter and aren't easily made conscious. (The ease with which they
are made conscious seems to be dependent on the listener being literate
in an alphabetic script, so it's not a general claim about all listeners.)

Martin