Leading Questions - Chapter 7

[Fred Nickols (990307.1835 ET)] --

Okay; vacation's over, time to get back to work and, boy, was Chapter 7 work!

Chapter 7 is about first order control systems - intensity control.

As I read it, the central nervous system (CNS) is at the heart of things.
It is, however, buffered from direct interactions with the environment by
way of first order systems, ones that deal with intensity. On the input
side we have nerve endings and on the output side we have muscles and
glands. Schematically, it looks something like this:

  The | | | | The
  Nerve | Boundary | CNS | Boundary | Muscles and
  Endings | | | | Glands

The first difficulty I encountered was with the equations on page 84. Try
as I might, I couldn't solve for p. Finally I figured it out. Mercy me;
my already strained math abilities were further taxed. Anyway, I finally
got it. More important, I got the point that the perceptual signal stays
at or near the amplitude of the reference signal or, as Bill writes, the
perceptual signal "tracks" the reference signal.

Then, on page 87, Bill writes, "Perception is controlled with reference to
the reference signal." Right about there I got a little confused. So, I'm
assuming that 'with reference to' in that sentence is equivalent to saying
"Perception is controlled in relation to the reference signal." If not,
correct my thinking.

At the beginning of this same paragraph on page 87, Bill writes, "There is,
however, one quality which is reliably controlled by the reference signal:
the perceptual signal." Now I'm really confused. I thought the perceptual
signal was controlled by behavior, that behaving kept perception aligned
with the reference signal. Here, I'm reading that the perceptual signal is
controlled by the reference signal. That sounds a lot like issuing a
command and having behavior bring perception into alignment with that
command. Is that correct? Somehow, I don't think so but I'm darned if I
can explain my way out of this predicament. Can we really say that the
perceptual signal is controlled by the reference signal?

On page 88, Bill writes, "There is the strong suggestion that the reference
signals come down saying, 'make it feel like this,' and a few tens of
milliseconds later the perceptual signals proceed back upward, 'feeling
like this.' As a side effect, forces are exerted on the external world."
I think I get the "side effect" comment, which is to say, at the level of
first-order systems there is no reference signal for an external condition,
only for internal conditions. Thus, any external changes are indeed side
effects. My question is perhaps getting ahead but it would seem to me that
if I want to pick up a book and move it from my desk to the bookcase, that
my perceptions are of the position of the book in relation to where I want
it to be and that any internal alignment of first-order reference and
perceptual signals could be viewed as the side effects of other controlled
variables. Comment please.

On page 89 it occurred to me that the neural "stuff" Bill was then citing
is now at least 25+ years old and, in many cases, older than that, which
leads me to ask of Bill: Has anything changed since then that alters your
thinking? If it has, I assume you've already updated your thinking in an
article or paper and could you point me to it? If not...well, Hmm.

Leading Questions

1. Can you perceive first-order effort-intensity signals? Try tensing
difference muscles. What is similar each time? (The amount of effort.)

I tried lifting upward the very heavy tile-topped kitchen table where I sat
reading Chapter 7 and making my notes. First I used my arm then my leg
(just above the knee). I cannot describe the "amount of effort" in ways
that allow me to compare them. What I can describe is what I would call
the "resistance" offered by the table (inertia?). Using that as my gauge,
I lifted first with my arm and then with my leg until the table began to
move. In both cases, what I would call the "weight" of the table "felt"
about the same. But I have no idea at all as to how this relates to
question 1 above.

2. Can you perceive the way in which a loud sound is like a bright light
or a pungent smell? How would each be experienced at the low end of the
intensity scale?

Again, I'm at a loss. I can imagine (and also recall) how a loud sound or
a bright light or a pungent smell "overwhelmed" my sensory apparatus and
caused me to wince, cover my ears, close my eyes, and hold my nose (and
breath), but I don't know how to compare those. At the low end of the
intensity scale I would imagine these stimuli are experienced as ordinary
perceptions or perceptual signals.

3. Can you raise and lower the total effort-intensity in an arm
independently of motion or position of the arm? Hold this book in one
hand. Can you vary the total effort-intensity without altering the net
upward forces supporting the book?

I think so. One way is to put my hand against the wall and exert pressure.
Effort goes up but neither the wall nor the arm moves. The muscles flex
and I lean into it but nothing budges. I can do the same thing by holding
the book in a fixed position and squeezing it. Nothing goes up or down but
effort increases.

4. In order for a sound to have a detectable pitch, it must have a
detectable loudness. Is the reverse true?

Ouch. This one made my memory and my head hurt. To be heard, sound must
have volume or loudness above some threshold level and it must also fall
within some frequency range (20 hertz to 20K hertz last time I looked).
So, any sound that can be heard must, as you say, have a detectable
loudness. Similarly, for a sound of any loudness to be heard, it must have
a detectable pitch or, no matter its volume, it won't be heard (although it
might well be felt).
Short answer: Yes.

5. In order for an edge to be visually detected, there must exist
detectable brightness. Is the reverse true?

Short answer here: No. "Edges," if I understand what Bill is talking about
are visual phenomena having to do with light reflected off objects. This
implies eyes open. So, I closed my eyes and played a flashlight over them.
I could detect varying intensities of light or brightness but no edges.
Again, my answer is, No.

What did I learn from Chapter 7? Well, the notion that the central nervous
system is "buffered" by first-order control systems is informative even if
I don't know what to do with that knowledge just yet. Another thought that
occurred to me is that intensity is the first level of knowing. There
might be something profound lurking in that but I don't know what it is
either (other than perhaps we are all much more tactile than we suspect and
that "tactile intelligence" -- if there is such a thing -- might be the
foundation for all intelligence).

In sum, coming away from Chapter 7, I have the sense that I have touched on
the foundation of signal processing by human beings but at such a basic
level as to be not yet terribly useful to me.

Regards,

Fred Nickols
Distance Consulting
http://home.att.net/~nickols/distance.htm
nickols@worldnet.att.net
(609) 490-0095

[From Rick Marken (990308.0950)]

Fred Nickols (990307.1835 ET) --

At the beginning of this same paragraph on page 87, Bill writes,
"There is, however, one quality which is reliably controlled by
the reference signal: the perceptual signal." Now I'm really
confused. I thought the perceptual signal was controlled by
behavior, that behaving kept perception aligned with the
reference signal. Here, I'm reading that the perceptual signal
is controlled by the reference signal. That sounds a lot like
issuing a command and having behavior bring perception into
alignment with that command. Is that correct?

Yes!

Somehow, I don't think so but I'm darned if I can explain my
way out of this predicament. Can we really say that the
perceptual signal is controlled by the reference signal?

Here's a case where Bill is using the word "control" informally.
What Bill means here by "controlled" is closer to "caused"; the
reference signal _causes_ the perceptual to take on a particular
value -- the value of the reference signal. Of course, we know
that this happens because there is a control loop in place that
_controls_ the perceptual signal, making it match the reference
signal. What Bill is saying is that if you could get into
someone's brain and vary one of their reference signals, what
you would find is that these variations reliably cause concomitant
variations in a perceptual signal. You would find, in other words,
that the reference signal functions precisely as an _independent
variable_ is supposed to function in behavior; it _causes_ changes
in a dependent variable (in this case, the perceptual input
signal).

I think it's perfectly OK to think of a reference signal as a
command for _input_. The problem with conventional psychology
is that it views these signals (efferent neural signals) as
commands for _output_. PCT shows clearly that a system that
operates by specifying (commanding) output cannot work in
a disturbance-prone world.

Best

Rick

···

--
Richard S. Marken Phone or Fax: 310 474-0313
Life Learning Associates e-mail: rmarken@earthlink.net
http://home.earthlink.net/~rmarken

[From Bruce Gregory (990308.1312 EST)]

Rick Marken (990308.0950)

I think it's perfectly OK to think of a reference signal as a
command for _input_. The problem with conventional psychology
is that it views these signals (efferent neural signals) as
commands for _output_. PCT shows clearly that a system that
operates by specifying (commanding) output cannot work in
a disturbance-prone world.

A command for input, but _only_ when the associated variable is being
controlled. You have a reference level for the distance you will follow
the car in front of you, but this reference level is a command for input
only when you are behind the wheel and paying attention to the traffic
you see. I only add this qualifier because it took me quite a while to
understand that this must be so.

Bruce Gregory

from Bill Powers (990309.1630 MST)]

Fred Nickols (990307.1835 ET) --

Chapter 7 is about first order control systems - intensity control.

As I read it, the central nervous system (CNS) is at the heart of things.
It is, however, buffered from direct interactions with the environment by
way of first order systems, ones that deal with intensity. On the input
side we have nerve endings and on the output side we have muscles and
glands. Schematically, it looks something like this:

The | | | | The
Nerve | Boundary | CNS | Boundary | Muscles and
Endings | | | | Glands

Exactly. Of course in a complete account, you must also show how muscles
and glands (as well as other causes in the environment) directly affect The
Nerve Endings, too.

The first difficulty I encountered was with the equations on page 84. Try
as I might, I couldn't solve for p. Finally I figured it out. Mercy me;
my already strained math abilities were further taxed. Anyway, I finally
got it. More important, I got the point that the perceptual signal stays
at or near the amplitude of the reference signal or, as Bill writes, the
perceptual signal "tracks" the reference signal.

So far you're doing fine. I'm very pleased that you stuck with the math
until you got it. That little investment will pay off in understanding.

Then, on page 87, Bill writes, "Perception is controlled with reference to
the reference signal." Right about there I got a little confused. So, I'm
assuming that 'with reference to' in that sentence is equivalent to saying
"Perception is controlled in relation to the reference signal." If not,
correct my thinking.

Finding the right words is a problem. When you say something is being
controlled, you have to specify with reference to what condition.

Suppose the perceptual signal has a value of 25 units (of some kind). Is it
under control? You can't tell unless you know what the reference signal's
value is. If the reference signal has a value of 200 or -11, the perceptual
signal is probably not under control, or very good control. If the
reference signal has a value of 26, and the perceptual signal never gets
far from that value (for instance, it ranges most of the time between 25
and 27), the perceptual signal is probably under control.

Suppose you find that the perceptual signal is continually changing at some
small rate. When you first observe it, it has a magntude of 25, and when
you observe it an hour later it has a magnitude of 3625. Is it under
control? Possibly yes! Suppose your record of observations shows that it's
changing at a rate of 1 unit per second, + or - 0.001 unit per second. This
suggests that not the magnitude, but the rate of change of magnitude is
under control, relative to a reference signal standing for 1.000 units _per
second_. Note that the perceptual signal now stands for a _rate of change_.
A constant reference signal means that the perceptual signal should also be
constant at the same magnitude, and this constant magnitude stands for a
_CONSTANT RATE OF CHANGE_ of the underlying variable. The larger the
magnitude of the perceptual signal, the faster the underlying variable is
changing. This implies a rate-sensitive transducer at the input.

At the beginning of this same paragraph on page 87, Bill writes, "There is,
however, one quality which is reliably controlled by the reference signal:
the perceptual signal." Now I'm really confused. I thought the perceptual
signal was controlled by behavior, that behaving kept perception aligned
with the reference signal. Here, I'm reading that the perceptual signal is
controlled by the reference signal. That sounds a lot like issuing a
command and having behavior bring perception into alignment with that
command. Is that correct?

Yes, mostly. The "command," however, is simply an example of the perceptual
signal as it will be when it has the right magnitude. If the perceptual
signal has a rate of firing such that 10 impulses per second represents 5
decibels of loudness, then the reference signal will be another neural
signal of the same kind. If this reference signal is a flow of 50 impulses
per second, then the perceptual signal will also have to be a flow of 50
impulses per second to match it. This means that the sound intensity
producing that perceptual signal will have to be adjusted to 25 decibels of
intensity.

Of course the nervous system doesn't need to know about these calibration
factors. It just acts on the muscles to turn the volume-control knob (or
tighten the diaphragm) so that the perceptual signal comes to 50 impulses
per second, or whatever the setting of the reference signal happens to be
at the moment. An observer with an audiometer will then measure 25 decibels
of sound, but the CNS doesn't care about that.

Somehow, I don't think so but I'm darned if I
can explain my way out of this predicament. Can we really say that the
perceptual signal is controlled by the reference signal?

Rick interpreted what I said correctly: it is the control organization, not
the reference signal, that really does the controlling. But the reference
signal _seems_ to determine the state of the perceptual signal; if you vary
the reference signal, the perceptual signal will vary in very close to the
same way, just as if it were directly determined by the reference signal.
Of course we know this effect is created indirectly.

On page 88, Bill writes, "There is the strong suggestion that the reference
signals come down saying, 'make it feel like this,' and a few tens of
milliseconds later the perceptual signals proceed back upward, 'feeling
like this.' As a side effect, forces are exerted on the external world."
I think I get the "side effect" comment, which is to say, at the level of
first-order systems there is no reference signal for an external condition,
only for internal conditions.

That's what I meant.

Thus, any external changes are indeed side
effects. My question is perhaps getting ahead but it would seem to me that
if I want to pick up a book and move it from my desk to the bookcase, that
my perceptions are of the position of the book in relation to where I want
it to be and that any internal alignment of first-order reference and
perceptual signals could be viewed as the side effects of other controlled
variables. Comment please.

You have to consider that the world we see doesn't always correctly reflect
the world that is. If you're manipulating the book while looking at your
hands in a mirror box, you may be adjusting the position of the book to
rest on top of some other object. The direct effect of your movements is to
place the perception of the book on the perception of the other object, but
a side-effect of doing this may be to place the real book two feet away
from where the other object really is. It's always the _perception_ that's
controlled; what's actually happening in the physical world may or may not
have some resemblance to what the perceptions say exists or is happening.

If you think even more deeply about this, you're realize that the world we
control _never_ corresponds to the physical world that is.

On page 89 it occurred to me that the neural "stuff" Bill was then citing
is now at least 25+ years old and, in many cases, older than that, which
leads me to ask of Bill: Has anything changed since then that alters your
thinking? If it has, I assume you've already updated your thinking in an
article or paper and could you point me to it? If not...well, Hmm.

I don't think that much has changed. Some people conjecture about chaotic
perceptions or perceptions depending on synchronized impulses and other
such stuff, but my opinion is that they're just blowing smoke. It doesn't
matter anyway, as long as there is _some_ kind of function relating what we
perceive to what is happening externally.

Leading Questions

1. Can you perceive first-order effort-intensity signals? Try tensing
difference muscles. What is similar each time? (The amount of effort.)

I tried lifting upward the very heavy tile-topped kitchen table where I
sat reading Chapter 7 and making my notes. First I used my arm then my
leg (just above the knee). I cannot describe the "amount of effort" in ways
that allow me to compare them.

How about "more" and "less"?

What I can describe is what I would call
the "resistance" offered by the table (inertia?). Using that as my gauge,
I lifted first with my arm and then with my leg until the table began to
move. In both cases, what I would call the "weight" of the table "felt"
about the same. But I have no idea at all as to how this relates to
question 1 above.

Question 1 was supposed to suggest that what you call the "weight of the
table" is actually a sense of the intensity of the effort required to lift
it. This sense of effort probably combines proprioceptive signals with
signals from skin pressure receptors. One thing we can be sure of: there
are no sensors for the weight of the table.

2. Can you perceive the way in which a loud sound is like a bright light
or a pungent smell? How would each be experienced at the low end of the
intensity scale?

Again, I'm at a loss. I can imagine (and also recall) how a loud sound or
a bright light or a pungent smell "overwhelmed" my sensory apparatus and
caused me to wince, cover my ears, close my eyes, and hold my nose (and
breath), but I don't know how to compare those. At the low end of the
intensity scale I would imagine these stimuli are experienced as ordinary
perceptions or perceptual signals.

Can you say that a loud sound, a bright light, and a pungent smell are all
at the upper end of some scale of intensities, while a faint sound, a dim
light, and a faint whiff of a smell are at the lower end? In terms of
_intensity of stimulation_ you can, I think (and hope) compare them. That
is, you can say a dim light and a faint sound are alike, while a dim light
and a pungent smell are different -- in terms of their intensity.

3. Can you raise and lower the total effort-intensity in an arm
independently of motion or position of the arm? Hold this book in one
hand. Can you vary the total effort-intensity without altering the net
upward forces supporting the book?

I think so. One way is to put my hand against the wall and exert >pressure.

Another way is just to tense opposing muscles against each other. You can
raise and lower total effort intensity in this way without moving the arm
or changing its net force applied to something else.

Effort goes up but neither the wall nor the arm moves. The muscles flex
and I lean into it but nothing budges. I can do the same thing by holding
the book in a fixed position and squeezing it. Nothing goes up or down but
effort increases.

Good examples.

4. In order for a sound to have a detectable pitch, it must have a
detectable loudness. Is the reverse true?

Ouch. This one made my memory and my head hurt. To be heard, sound must
have volume or loudness above some threshold level and it must also fall
within some frequency range (20 hertz to 20K hertz last time I looked).
So, any sound that can be heard must, as you say, have a detectable
loudness. Similarly, for a sound of any loudness to be heard, it must have
a detectable pitch or, no matter its volume, it won't be heard (although it
might well be felt).
Short answer: Yes.

The question was, is it true that in order to have a detectable loudness,
the sound must have a detectable pitch? I think the answer is no: A sound
can be so faint, or so brief, or so complex, that you can't tell what its
pitch is. Similarly for light: a light can be so dim that you can't tell
what color it is. Also, a white noise sound has no specific detectable
pitch (sensation), yet it has a detectable loudness (intensity).

5. In order for an edge to be visually detected, there must exist
detectable brightness. Is the reverse true?

Short answer here: No. "Edges," if I understand what Bill is talking about
are visual phenomena having to do with light reflected off objects. This
implies eyes open. So, I closed my eyes and played a flashlight over them.
I could detect varying intensities of light or brightness but no edges.
Again, my answer is, No.

"Is the reverse true?" translates to "Is it true that in order for a
detectable brightness to exist, there must be a detectable edge?" I think
your flashlight experiment demonstrated clearly that the answer is no, as
you concluded. An edge can exist in a (monochromatic) visual field only
where two different intensities exist.

The point of these questions was to convey what is meant by a "higher
level" of perception -- one perception is of a higher level than another if
it depends for its existence on the existence of the other. Edges cannot
exist unless some brightnesses exist, but the reverse is not true.
We can see, by this definition, that edges are of a higher level than
brightness. All the levels of perception I have defined satisfy this
assymetrical relationship. I consider these dependencies of some
perceptions on others to be a profoundly significant fact of nature -- our
own nature.

What did I learn from Chapter 7? Well, the notion that the central
nervous system is "buffered" by first-order control systems is informative
even if I don't know what to do with that knowledge just yet. Another
thought that occurred to me is that intensity is the first level of >knowing.

I, too, think that is true. At the first level of experience of the world,
all we experience is an amount, unclassified in any other way.

There
might be something profound lurking in that but I don't know what it is
either (other than perhaps we are all much more tactile than we suspect
and that "tactile intelligence" -- if there is such a thing -- might be
the foundation for all intelligence.

These relationships apply to ALL sensory modalities, not just touch. That's
why there were leading questions about vision, sound, and smell. You can
make up similar examples in all other modalities, too.

In sum, coming away from Chapter 7, I have the sense that I have touched
on the foundation of signal processing by human beings but at such a basic
level as to be not yet terribly useful to me.

Another message: even at the first level, we cannot experience the world
directly. And another: at the first level, all perceptual signals are alike.

Best,

Bill P.

[From Fred Nickols (990310.1620 EST)] --

Bill Powers (990309.1630 MST)]

Rick interpreted what I said correctly: it is the control organization, not
the reference signal, that really does the controlling. But the reference
signal _seems_ to determine the state of the perceptual signal; if you vary
the reference signal, the perceptual signal will vary in very close to the
same way, just as if it were directly determined by the reference signal.
Of course we know this effect is created indirectly.

Okay; that answers my concern.

On page 88, Bill writes, "There is the strong suggestion that the reference
signals come down saying, 'make it feel like this,' and a few tens of
milliseconds later the perceptual signals proceed back upward, 'feeling
like this.' As a side effect, forces are exerted on the external world."
I think I get the "side effect" comment, which is to say, at the level of
first-order systems there is no reference signal for an external condition,
only for internal conditions.

That's what I meant.

Thus, any external changes are indeed side
effects. My question is perhaps getting ahead but it would seem to me that
if I want to pick up a book and move it from my desk to the bookcase, that
my perceptions are of the position of the book in relation to where I want
it to be and that any internal alignment of first-order reference and
perceptual signals could be viewed as the side effects of other controlled
variables. Comment please.

You have to consider that the world we see doesn't always correctly reflect
the world that is. If you're manipulating the book while looking at your
hands in a mirror box, you may be adjusting the position of the book to
rest on top of some other object. The direct effect of your movements is to
place the perception of the book on the perception of the other object, but
a side-effect of doing this may be to place the real book two feet away
from where the other object really is. It's always the _perception_ that's
controlled; what's actually happening in the physical world may or may not
have some resemblance to what the perceptions say exists or is happening.

If you think even more deeply about this, you're realize that the world we
control _never_ corresponds to the physical world that is.

I follow your response to my question and I agree with what you say but
what you say doesn't answer my question. I'll try it again -- in different
terms.

        Can reference and perceptual signals at levels lower in the
        hierarchy be considered as "side effects" of reference and
        perceptual signals at higher levels (e.g., in moving the book
        in physically moving the book operating in ways that might be
        considered "side effects" of my higher-order goal of moving
        the book)?

        Hmm. Having asked that dumb question I'll answer it myself:
        No, they not "side effects," they're essential lower-order
        operations necessary to the attainment of the higher-order
        congruence between reference and perception.

        Comment?

Leading Questions

1. Can you perceive first-order effort-intensity signals? Try tensing
difference muscles. What is similar each time? (The amount of effort.)

I tried lifting upward the very heavy tile-topped kitchen table where I
sat reading Chapter 7 and making my notes. First I used my arm then my
leg (just above the knee). I cannot describe the "amount of effort" in ways
that allow me to compare them.

How about "more" and "less"?

Well, as I indicated below, the level of effort felt about the same,
although in the one case I was exerting force upward using my arm and in
the other I was using my leg. Perhaps I should have said the effort
exerted felt about the same instead of converting that into the "weight" of
the table. (That said, the muscle tension I experienced in my arm felt
different from the muscle tension I experienced in my leg.)

What I can describe is what I would call
the "resistance" offered by the table (inertia?). Using that as my gauge,
I lifted first with my arm and then with my leg until the table began to
move. In both cases, what I would call the "weight" of the table "felt"
about the same. But I have no idea at all as to how this relates to
question 1 above.

Question 1 was supposed to suggest that what you call the "weight of the
table" is actually a sense of the intensity of the effort required to lift
it. This sense of effort probably combines proprioceptive signals with
signals from skin pressure receptors. One thing we can be sure of: there
are no sensors for the weight of the table.

I think we are agreed.

2. Can you perceive the way in which a loud sound is like a bright light
or a pungent smell? How would each be experienced at the low end of the
intensity scale?

Again, I'm at a loss. I can imagine (and also recall) how a loud sound or
a bright light or a pungent smell "overwhelmed" my sensory apparatus and
caused me to wince, cover my ears, close my eyes, and hold my nose (and
breath), but I don't know how to compare those. At the low end of the
intensity scale I would imagine these stimuli are experienced as ordinary
perceptions or perceptual signals.

Can you say that a loud sound, a bright light, and a pungent smell are all
at the upper end of some scale of intensities, while a faint sound, a dim
light, and a faint whiff of a smell are at the lower end? In terms of
_intensity of stimulation_ you can, I think (and hope) compare them. That
is, you can say a dim light and a faint sound are alike, while a dim light
and a pungent smell are different -- in terms of their intensity.

Boy, that feels an awful lot like apples and oranges to me. I see your
point, but I'm inclined to think that the intensity of a bright light, a
loud sound and a pungent smell are very different animals. "Bright,"
"loud," "pungent," "faint" and "dim" are abstractions, words, labels that
convey something about a scale of intensity but I don't know that the
sensation of intensity via sight, hearing, smell, taste, touch and
kinesthesia are at all comparable. I know you're arguing that they are at
the level of intensity and that might be true in a purely biological or
chemical or physical sense but I'm darned if I can get my head around it in
an experiential sense. I think I experience them differently.

4. In order for a sound to have a detectable pitch, it must have a
detectable loudness. Is the reverse true?

Ouch. This one made my memory and my head hurt. To be heard, sound must
have volume or loudness above some threshold level and it must also fall
within some frequency range (20 hertz to 20K hertz last time I looked).
So, any sound that can be heard must, as you say, have a detectable
loudness. Similarly, for a sound of any loudness to be heard, it must have
a detectable pitch or, no matter its volume, it won't be heard (although it
might well be felt).
Short answer: Yes.

The question was, is it true that in order to have a detectable loudness,
the sound must have a detectable pitch? I think the answer is no: A sound
can be so faint, or so brief, or so complex, that you can't tell what its
pitch is. Similarly for light: a light can be so dim that you can't tell
what color it is. Also, a white noise sound has no specific detectable
pitch (sensation), yet it has a detectable loudness (intensity).

I see the error of my un-PCT-like ways in the case above. I was thinking
of the sound in the "out there" instead of "in here" sense, that is, as the
air wave disruptions at the source of the sound, not as I perceived it.
That said, I cannot image a sound so faint or brief or complex that I can't
tell something about its frequency (i.e., real high, real low, or
whatever). Can you give me an example or two?

5. In order for an edge to be visually detected, there must exist
detectable brightness. Is the reverse true?

Short answer here: No. "Edges," if I understand what Bill is talking about
are visual phenomena having to do with light reflected off objects. This
implies eyes open. So, I closed my eyes and played a flashlight over them.
I could detect varying intensities of light or brightness but no edges.
Again, my answer is, No.

"Is the reverse true?" translates to "Is it true that in order for a
detectable brightness to exist, there must be a detectable edge?" I think
your flashlight experiment demonstrated clearly that the answer is no, as
you concluded. An edge can exist in a (monochromatic) visual field only
where two different intensities exist.

The point of these questions was to convey what is meant by a "higher
level" of perception -- one perception is of a higher level than another if
it depends for its existence on the existence of the other. Edges cannot
exist unless some brightnesses exist, but the reverse is not true.
We can see, by this definition, that edges are of a higher level than
brightness. All the levels of perception I have defined satisfy this
assymetrical relationship. I consider these dependencies of some
perceptions on others to be a profoundly significant fact of nature -- our
own nature.

Here, too, I get your point and I think I also got the "correct" answer but
your explanation does raise a question. I would have said "different" not
"higher." Does this mean that the hierarchy of levels is predicated on
dependency relationships?

Another message: even at the first level, we cannot experience the world
directly. And another: at the first level, all perceptual signals are alike.

Again, a question. You say, "...at the first level, all perceptual signals
are alike." I see how that might be true biologically, chemically,
electrically, or whatever, although I don't know enough about how the
central nervous system processes visual, auditory, olfactory etc sensations
to agree or disagree in any informed way. I still think I experience these
sensations differently. To me, that means my conscious experience of such
sensations must be at least one level up from the first level. If that's
the case, then I go back to the faint sound and dim light discussion above.
I'll readily agree that I might sense a light or sound so dim or faint
that I'm not consciously aware of it (which would suggest two thresholds:
one for sensing, and one for conscious awareness). If that's the case, I
can reconcile the two. If that's not the case, then I don't see how I can
consciously detect a sound but not recognize something about its frequency
or pitch. Sorry to be such a pest.

Regards,

Fred Nickols
Distance Consulting
http://home.att.net/~nickols/distance.htm
nickols@worldnet.att.net
(609) 490-0095

···

from my desk to the bookcase, are the control systems involved

[From Bill Powers (990311.1011 MST)]

Fred Nickols (990310.1620 EST)] --

       Can reference and perceptual signals at levels lower in the
       hierarchy be considered as "side effects" of reference and
       perceptual signals at higher levels (e.g., in moving the book
       from my desk to the bookcase, are the control systems involved
       in physically moving the book operating in ways that might be
       considered "side effects" of my higher-order goal of moving
       the book)?

       Hmm. Having asked that dumb question I'll answer it myself:
       No, they not "side effects," they're essential lower-order
       operations necessary to the attainment of the higher-order
       congruence between reference and perception.

One of the nicest things about PCT is that once you've reached a certain
threshold of understanding, you can start to answer your own questions --
and KNOW that the answer is right.

I cannot describe the "amount of effort" in ways
that allow me to compare them.

How about "more" and "less"?

Well, as I indicated below, the level of effort felt about the same,
although in the one case I was exerting force upward using my arm and in
the other I was using my leg. Perhaps I should have said the effort
exerted felt about the same instead of converting that into the "weight" of
the table. (That said, the muscle tension I experienced in my arm felt
different from the muscle tension I experienced in my leg.)

The basic problem you're having here -- and which everyone has to some
degree that varies with time -- is that you're looking at one level of
perception while using all your higher levels to look at it with. It is
very hard to stop using the higher levels, or to ignore what they're
reporting. Intensity perception is perception of intensity -- AND NOTHING
ELSE. Of course while you're considering intensities, you're also
considering (at higher levels) _what kind_ of intensity, and _what patterns
in space_ they form, and _how they are changing_, and _what temporal
patterns_ they follow, and _what relationships they have to other
perceptions_, and _what categories they belong to (names), and so forth.

Note the extremely interesting implication that we can consciously perceive
the signals leaving sensory endings.

But the natural way to perceive has all 11 levels being projected into a
single experiential field. What PCT does for us, or what I have tried to do
in connection with PCT, is to sort out these perceptions into levels, so we
can begin to recognize the dependencies that are there. In this way we can
begin to see a hierarchical structure in the world of experience, such that
some classes or kinds of perceptions depend according to some simple
principles on other classes or kinds of perceptions. I'm a bit diffident
about this hierarchy because sometimes I can see what seem to be exceptions
or reversals, but I think the principle will hold up -- at a given moment,
we are acting on the world to _alter_ some perceptions as a way of
_controlling_ other perceptions that depend on them.

Question 1 was supposed to suggest that what you call the "weight of the
table" is actually a sense of the intensity of the effort required to
lift it.

I think we are agreed.

Excellent! This can be a tough point to get across.

Can you say that a loud sound, a bright light, and a pungent smell are all
at the upper end of some scale of intensities, while a faint sound, a dim
light, and a faint whiff of a smell are at the lower end? In terms of
_intensity of stimulation_ you can, I think (and hope) compare them. That
is, you can say a dim light and a faint sound are alike, while a dim light
and a pungent smell are different -- in terms of their intensity.

Boy, that feels an awful lot like apples and oranges to me. I see your
point, but I'm inclined to think that the intensity of a bright light, a
loud sound and a pungent smell are very different animals.

This is another manifestation of the problem of looking from too high a
level at a low-level perception. Apples and oranges are similar at the
level of perceiving curvature: they are both round. Roundness or curvature
is probably perceived at about the second level. Forms are perceived at the
third level -- but they're not categorized or named, if I am right, until
we get to the seventh level or higher.

I see the error of my un-PCT-like ways in the case above. I was thinking
of the sound in the "out there" instead of "in here" sense, that is, as >the
air wave disruptions at the source of the sound, not as I perceived it.
That said, I cannot image a sound so faint or brief or complex that I >can't
tell something about its frequency (i.e., real high, real low, or
whatever). Can you give me an example or two?

If you pay attention to the level of perceptions at which pitch is
perceived, you can probably always get at least a tiny signal from them.
But a click made from white noise gives only a very small signal, while you
remain quite able to tell how loud the click is (was).

Here, too, I get your point and I think I also got the "correct" answer
but your explanation does raise a question. I would have said "different"
not "higher." Does this mean that the hierarchy of levels is predicated
on dependency relationships?

As I said above, yes. In order to _control_ one level of perceptions, you
must _vary_ perceptions at least one level down (by means of altering
reference signals for the systems that control those perceptions). "Higher"
perceptions as I define that concept are those that are functions of
(depend on) "lower" perceptions, and that are controlled by varying
lower-level perceptions. Remember that "perception" in PCT has nothing to
do with consciousness: the term means only that there is a neural signal in
an afferent neural channel. A perceptual signal can exist without our being
conscious of it (as the signal from the interface between your butt and the
chair right now).

Another message: even at the first level, we cannot experience the world
directly. And another: at the first level, all perceptual signals are alike.

Again, a question. You say, "...at the first level, all perceptual signals
are alike." I see how that might be true biologically, chemically,
electrically, or whatever, although I don't know enough about how the
central nervous system processes visual, auditory, olfactory etc sensations
to agree or disagree in any informed way. I still think I experience these
sensations differently.

Same answer as above: at the lowest level of perception, the neural signals
are emitted directly from sensory endings and report, primarily, the
intensity of physical stimulation (ignoring some whistles and bells). So if
you consciously pay attention ONLY to first-order perceptions, you
experience ONLY a quantity, without anything to identify what it is a
quantity OF. It's a pure number, indicated by a train of impulses in
distinguishable from the individual impulses in any other input channel.

To me, that means my conscious experience of such
sensations must be at least one level up from the first level. If that's
the case, then I go back to the faint sound and dim light discussion above.

There you're starting to see the answer to your problems.

I'll readily agree that I might sense a light or sound so dim or faint
that I'm not consciously aware of it (which would suggest two thresholds:
one for sensing, and one for conscious awareness).

Try: one at level 1, and one at level 2. Consciousness is irrelevant.

If that's the case, I
can reconcile the two. If that's not the case, then I don't see how I can
consciously detect a sound but not recognize something about its frequency
or pitch. Sorry to be such a pest.

No, no, no, I'm enjoying the hell out of this. I went through exactly the
same mental processes trying to sort all this out, before I had a wrinkle
to grace my youthful face. I think lots of other people have, too, although
most of them stopped before they arrived at a coherent theory.

Wonderful of you to go through all this effort. I'm sure many others are
appreciating it, too.

Best,

Bill P.