what's the difference?

[From: Bruce Nevin (Wed 920424 08:22:46)]

I suspect that there is more than one sort of thing being called
adaptation. I have proposed before that one of these is a change in the
value of a reference signal, basing it on short-term memory more than on
long-term memory. This would be real adaptation. Another sort of thing
might be reduction in gain. Later repetitions of a word in discourse
are produced with less careful articulation than the first occurrance,
Martin tells us (a fact that, to my delight, fits very well with the
Harrisian notion of reductions). With a reduction in gain there might
be a statistical tendency but not the individual consistency that is the
hallmark of control.

There is always the possibility of boredom, listening to 70 repetitions
of a synthesized while (whilst) clenching ones tongue between one's
teeth.

The idea of adapting the reference signal has an interesting twist for
language learning. We do accomodate small shifts of dialect without
noticing, preserving contrast of words; we also resist large dialectal
differences at a different level of control, the contrast between the
kind of person who speaks noticeably that way and the kind of person
with whom I am most familiar. If it were possible to vary the relevant
parameters for a difference in pronunciation (say English vs. Spanish
VOT) in ongoing dialog with the student, the student might "adapt" to
the new reference values in graduated steps, never encountering a
differential sufficient for control on the self-image level. One can
imagine a SF world, where the student was immersed in an environment
with androids whose reference signals were able to be tuned gradually in
this way. I'm not sure if it would be possible for a human instructor
to make the gradual adjustments in a consistent way--sensitive always to
the student's current and changing settings of those signals, and while
carrying on natural and engaging conversation.

(Martin Taylor 920623 21:15) --

Replying to me (920423 08:32:46)

One possibly fruitful way to approach this is by attributing
differentiating perceptions to the individuals in memory and
imagination.
...

Suppose we have ECSs (elementary control systems) controlling for ways
to differentiate between like perceptions by identifying other
perceptions associated with them as attributes. Is there any reason
this is implausible? In such a way we might develop control of category
perceptions.

One way to track four dots that soon becomes intractible is using their
history ("the one that started in the northwest corner"). An ECS alert
for differentia might entertain various hypotheses ("the bounciest one")
and develop a history of them (". . . is tired now"). A story, not in
words but in remembered perceptions. ...

I find this approach highly plausible and natural within the HPCT
structure. Does it answer your own question? I think it answers mine,
which was supposed to mirror yours.

Yes, I hope so, and thank you for taking up the question and
rearticualting it so well.

Now, what might a difference-detector ECS accept as input? Two signals
from an ECS, one associated with one set of signals from other ECSs,
another associated with an intersecting but different set. A
discontinuity in the signal or signals that stay the same, reflecting a
discontinuity in sensory input or a shift of attention. (Attention
involves at least the real or imagined focus of sensory organs on a
target and the adjustment of gain on selected ECSs, as for example
tuning out extraneous noise for conversation in a crowd.) The
discontinuity marks a shift from one individual to another, unless the
difference-detector itself reports continuity (no differences that make
any difference).
        a m p a b c
         \ | / \ | /
      b -- X -- q m -- X -- n
         / | \ / | \
        c n r p q r

  Individual Individual Individual Individual
  A = X plus B = X plus A = X plus B = X plus
  {abcmn} {pqrmn} {mabcpqr} {nabcpqr}

Here are two hypothetical cases of "detecting an X" plus associated
perceptions {abcmnpqr} that may be present. X is a category perception.

My proposal regarding category perceptions is that they develop from the
association of e.g. {abcmn}, {pqrmn}, {mabcpqr}, {nabcpqr} as distinct
individuals by a difference-detector. The difference-detector then
constitutes the category perception out of these perceptions of
attributes. Any association-set like {abcmn} or {pqrmn} (or in the
second hypothetical case, any association-set like {mabcpqr} or
{nabcpqr}) indicates that an X is present. Were one to define an X, one
would say anything that has attributes {mn} (in the first case), with
other attributes {abc} or {pqr} optional. (In the second case, the
defining attributes would be {abcpqr} and the variability would be
between m and n.)

According to this proposal, there are difference-detectors, and there
are associations of perceptual signals (attributes) in associative
memory, but there are no category detectors per se. Does this still
sound feasible and sensible?

  Bruce
  bn@bbn.com

[From Rick Marken (920624.0900)]

Bruce Nevin (Wed 920424 08:22:46) says:
                    ^ (where the hell is BBN. It's JULY on the west coast)

I suspect that there is more than one sort of thing being called
adaptation.

That's for sure. I think what the VOT people were trying to do was
adapt in the sense of fatiguing a sensory system. Adaptation is a well
known perceptual effect. Probably the best known are color aftereffects.
Remember the green and orange striped american flag in your introductory
psych text. When you stare at it for a while (1 min say) you are presumably
fatiguing one side of an opponent process color system -- the green is
fatiguing the green side of a red-green system. If you look at white paper
after this adaptation (white has both "red" and "green" in it) the green
system is all tuckered out -- so it can't fire as strongly as the red side,
and it can't inhibit the red side as strongly as the red can inhibit the
green. Hence, you see ol' glory in red white and blue after adapting to
the green, orange and yellow (I think? -- I can't remember color
compliments).

This kind of adaptation also happens with motion (the "waterfall" effect).
I think Bill Powers was actually helping with a control study based on this
kind of adaptation. If you stare at a waterfall (downward retinal motion)
for some time, then look at the stationary cliff next to the waterfall,
the cliff seems to move UP.

These adaptation effects are a nice substitute for hallucinogenic drugs -- and
they also are also a nice tool for studying perceptual processing. I suppose
that the VOT people imagined that there was detector for VOT. But I don't
know how they thought the adaptation might work. I guess there would
have to be some idea what the "neutral" value of VOT is (like the stationary
cliff in the waterfall effect and white in the color effect). I suppose zero
VOT would be the neutral value? Anyway, after adaptation to a VOT of +X, a
zero VOT should then sound like -Y. It's not clear what the effect should
be if you present a VOT near the adapted value (as they did in the study).
In the color and waterfall effects, there would be virtually NO effect.
That is, if you adapt to green and then show green, it still looks green.
If you adapt to "up movement" and then show up movement it still looks
up.

Maybe they just did the VOT study wrong. If there really is a VOT detector
that adapts, then if you adapt the detector to a +58msec VOT then a
sound with zero VOT should sound like it has an approximately -58 VOT.
So to produce the sound correctly, the subject would have to delay the
VOT (which is usually zero) by about 58 msec.

Such a study should be done quantitatively (varying the degree of adapting
VOT over some range and watching for quantitative opposition by the speaker.
If the opposition is not perfect (correlation between adapting VOT and
spoken VOT = .99 or greater) then keep looking for the controlled variable.

Best regards

Rick

ยทยทยท

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Richard S. Marken USMail: 10459 Holman Ave
The Aerospace Corporation Los Angeles, CA 90024
E-mail: marken@aero.org
(310) 336-6214 (day)
(310) 474-0313 (evening)

[Martin Taylor 920624 13:00 (still June in Toronto)]
(Rick Marken 920624.0900)

Bruce Nevin (Wed 920424 08:22:46) says:
                   ^ (where the hell is BBN. It's JULY on the west coast)

I suspect that there is more than one sort of thing being called
adaptation.

That's for sure. I think what the VOT people were trying to do was
adapt in the sense of fatiguing a sensory system. Adaptation is a well
known perceptual effect. Probably the best known are color aftereffects.
Remember the green and orange striped american flag in your introductory
psych text. When you stare at it for a while (1 min say) you are presumably
fatiguing one side of an opponent process color system -- the green is
fatiguing the green side of a red-green system. If you look at white paper
after this adaptation (white has both "red" and "green" in it) the green
system is all tuckered out -- so it can't fire as strongly as the red side,
and it can't inhibit the red side as strongly as the red can inhibit the
green. Hence, you see ol' glory in red white and blue after adapting to
the green, orange and yellow (I think? -- I can't remember color
compliments).

This kind of adaptation also happens with motion (the "waterfall" effect).
I think Bill Powers was actually helping with a control study based on this
kind of adaptation. If you stare at a waterfall (downward retinal motion)
for some time, then look at the stationary cliff next to the waterfall,
the cliff seems to move UP.
...
That is, if you adapt to green and then show green, it still looks green.
If you adapt to "up movement" and then show up movement it still looks
up.

Oh, wow...disinformation piled on misinformation! I know that many people
think of aftereffects as the consequence of fatigue, but they can't be, at
least in most cases and perhaps in all.

Disinformation first: It is NOT true that if you adapt to up movement and
then show up it still looks up. The aftereffect ADDS to the real movement,
so that you can get an impression of zero movement by presenting the correct
amount of up movement. Things obviously appear continuously higher, but there
is no apparent movement. The perception of movement is separate from the
perception of change of position. I did lots of experimental and theoretical
work in this area in the 60's, and one thing that subsequent work cannot
change is that the phenomenology is very complex. A naive view based on
"adpaptation=fatigue" cannot work because it predicts a lot of phenomena
wrongly. "Adaptation=improved perceptual precision" accounts for quite a
few of the phenomena that "adaptation=fatigue" does not, and predicts
numerically as well as qualitatively. In the red-green case, it is possible
(even likely) that fatigue plays a part. In the movement case, it is less
probable, and when we come to the more shape-based aftereffects, it is not
likely at all.

What control study was Bill doing? Maybe Bill can answer. I did several
studies around 1962-3 in which I had people counter the after-effect of motion,
to measure its time course. I asked them to keep the perceived motion at zero
after a period of viewing the moving thing. The decay of the after-effect
was double exponential, quantitatively proportional to the square root of
the duration of the adaptation. There are at least two effects there. The
neutralization of the adapting percept, on the other hand, is logarithmic in
the square root of time for at least 10 minutes of observation, and perhaps
much longer. It is different again. (Reference examples: Perceptual and
Motor Skills, 1963, 16, 119-129; 1963, 16, 513-519; 1964, 18, 885-888;
Perception and Psychophysics, 1966, 1, 113-119).

I don't follow Rick's analysis of the VOT detector system at all:

Maybe they just did the VOT study wrong. If there really is a VOT detector
that adapts, then if you adapt the detector to a +58msec VOT then a
sound with zero VOT should sound like it has an approximately -58 VOT.
So to produce the sound correctly, the subject would have to delay the
VOT (which is usually zero) by about 58 msec.

If there really is a VOT detector, it asserts whatever VOT is appropriate
for the phoneme in question as a reference. Zero VOT has no special
significance, and may not even be auditorily identifiable outside its
effect on the categorization of a phoneme. Even if zero were a special
reference point for VOT, as "vertical" is in vision because of gravity, one
would expect adaptation to +50 msec to have an effect no greater than about
5 msec on the perception of zero. And that 5 msec would be different for
other non-zero values of VOT, being probably (though not necessarily) of
different sign in different regions of absolute VOT.

Bruce is right. There are several different effects of adaptation. Adaptation
is a procedure, not a "perceptual effect". The adaptation procedure can
lead to fatigue, to excitation, to changes in the relative precision of
perception at different places on a continuum, to the diminution of deviations
from a reference (independent of fatigue), and to who knows what else.
These in turn lead to perceptual effects, which may differ accordinag to
circumstances, for any of the mechanisms.

Rick often proclaims that all psychological studies done outside the
control paradigm are worthless. This shouldn't give him the right to assert
his own view of the world that they study, in contradiction to the results
they obtain. You can't claim better truth by throwing away data than by
looking at what data you have, however wrongheaded the data gatherers might
have been. A solipsist world is not the domain of science.

Such a study should be done quantitatively (varying the degree of adapting
VOT over some range and watching for quantitative opposition by the speaker.
If the opposition is not perfect (correlation between adapting VOT and
spoken VOT = .99 or greater) then keep looking for the controlled variable.

Yes, one would have to do soemthing like that, if we could rig a vocoder-like
system to modify the VOT of the subject's own productions. But since at least
part of the sensation leading to the VOT perception is likely to be from
internal sources (feeling the vibration in the throat, for example), it would
be hard to expect such high correlations even if one could devize a real-time
VOT-shifter.

Sorry to be so harsh, Rick, but that message really seemed wrongheaded, if
not bull (headed).

Martin