FW: Insights into level 5 (?)

[Bruce_Gregory8]

i.kurtzer (981101.2100EST)

From Bill Powers (981031.1005 MST)

>i.kurtzer (981029.1901)

>Amplitude should already be handled by any continuous scalar signal

about

>one quality. We don't need two perceptual functions for detecting light
>and detecting how much.

Yes, we do. Intensity says there is some amount of a perception. "Light"
says it is a particular kind of sensation, as opposed to warmth or
sweetness.

We, the way that we have arranaged the hierarchy, yes.
We have intensities below sensations. One the side, I have some
reservations about Intensities at the
lowest level..because A)all sensory tranducers are already
functionally tuned to preferred stimuli so there is no reason to "build
this up" from intensities B) i cannot think of any intensity I have
noticed without it being already in the context of a sensation. So I have
seen "brighter" blues than other blues, but ALWAYS with blue..or green
or whatnot, but never "bright" in absence of any sensation. This is in
contrast to how we can determine the independence of sensation from
configuration as there I can have blue's and green's without any
configuration.
That's an aside just to indicate I am game for switching and swapping
levels.
So for a less contentios example: let's say "blue". Here we can have "no"
to "a whole bunch" of blue indicted by a scalar signal. Given the blue
PIF we don't need an extra "how much" detector/PIF. How much is already
indicated by the value of the scalar. Every signal carries this "how
much".

>How much is given by the scalar value and "that
>its a light detector" is given by its relationship to the world--as seen
>by us.

Perceptual systems don't perceive detectors, nor do they perceive the
world. They perceive only signals. All neural signals are alike, so it's
only the way a signal is handled in a perceptual input function that
identifies it.

I agree with all of that as a "working hypothesis", though there must be
some perceptual system that perceives "detectors" as we are talking about
it But for me PIF and "detector" are synomous in the above.

Are you abandoning the idea of a layered hierarchy with each level being a
function of levels below it?

Not at all. Just wondering how many we should have. I think event and
sequence are marvelous..intensity and category I could do without.

>Further, since there should be a continuos scalar of Transitions,
>rate should also be non-problematic.

Rate, at the transition level, is supposed to be an analog signal which,
when constant, represents a continuous change occurring at a steady rate:
the constant motion of the second-hand of a clock, or of a ceiling fan, or
a waterfall, is an example. Repetition rate, at the next level (?) is a
complex variation of configurations and transitions that recurs at

specific

intervals. The least possible number of repetitions is one, reducing the
perception to our former definition of an event.

Its seems any repetition is an event. I can't think of one otherwise.
Can anyone offer a counter-example.

Creating a repetitive cycle requires some sort of pattern generator to
serve as an output function, an oscillator or a more complex device, which
has inputs that can vary its speed of operation, the amplitude of its
output signal variations, and the phase of its output (advancing or
retarding the starting point). The controlled perceptions at this level
would correspond to the dimensions in which the operation of the pattern
generator can be varied.

A good example of control at this level is one person using a finger to
track another person's finger. The other person moves the target finger up
and down in a regular sine-wave pattern, gradually increasing the speed
until the motion is too fast for tracking random movements. Then the

target

person abruptly freezes the target finger in space. The tracking person
continues to produce the sine-wave motion for several tenths of a second,
showing that it is being independently produced by an internal sine-wave
generator that is adjusted in amplitude, frequency, and phase to match the
target movements.

This is different from tracking a randomly moving target. When a
randomly-moving target is abruptly frozen in space, the tracker stops
moving in a much shorter time. The delay is also shorter when a person is
tracking a slow motion in which no independent generator is required.

This is a great example..but how that requires a new level of perception
is another thing altogether.

>So it seems to me the dimensions are
>already there in the model. For example, to have any real

pirouette--which

>is an event--we must have some speed at which she is turning and some
>degree of tightness of the ankle cross and "hoopness" of the two arms.

So

>we have a pirouette, an event, with a particular tempo and amplitude as
>given by the configuration, transition, and relationship levels.

Sorry, but they have to be _given_ reference signals changing in such a

way

that they produce changes at the right speed of repetition.

I wasn't talking about how someone produces these regularies..Just that we
can see these regularities.

You have to be
very careful here not to superimpose your own higher-level perceptions on
lower systems that lack the ability either to perceive or control what
you're perceiving. After all, you can always claim that a spinal reflex
controls a relationship between an applied force and a muscle force that
opposes it. But that's your own relationship level talking.

I super-duper agree.

> Now we
>could arrange pirouettes with others kicks and jumps each different
>and malleable in duration, extent, and inter-duration.

_WHO_ could arrange that? A higher system. But there is no level in the
existing hierarchy that can perceive and control durations.

We'd better let this idea age for a while longer.

Agreed. And I'll drop it if you want to get back to it later. But on the
"who" can arrange--I am talking about US foremost. WE
can see a quick hop followed by two long strides. Now for how WE
have formally chopped up our world we have Events. Events
include "hopping" and "making strides" and both occur faster or slower in
real life. And it seems this "faster" and "slower" should be the output
signal of the PIF at the transition level. So if you had a sequence
of 3quickT's-2slowP's-3quickT's we should be able to deal with
these at the event level and below without any new levels.

i.

[Bill_Powers1]

[From Bill Powers (981102.-0725 MST)]

i.kurtzer (981101.2100EST)--

We, the way that we have arranaged the hierarchy, yes.
We have intensities below sensations. One the side, I have some
reservations about Intensities at the
lowest level..because A)all sensory tranducers are already
functionally tuned to preferred stimuli so there is no reason to "build
this up" from intensities B) i cannot think of any intensity I have
noticed without it being already in the context of a sensation. So I have
seen "brighter" blues than other blues, but ALWAYS with blue..or green
or whatnot, but never "bright" in absence of any sensation.

"Bright" is the name of a sensation. The name of the corresponding
intensity signal might be "lots of stimulation" without identifying the
modality.

Read Kofka, the old Gestalt psychologist. It is possible to adopt a
viewpoint in which one is unable to say whether a stimulus was a flash or
light or a click of sound. He called the intensity level the "sensorium
commune."

This is in
contrast to how we can determine the independence of sensation from
configuration as there I can have blue's and green's without any
configuration.

Remember that I'm an engineer, not a philosopher. The lowest level of
perception, in my model, consists of those neural signals that come
directly out of sensory receptors. According to our physical models of the
world, the cause of a neural signal is a physical variable acting on the
sensory receptor to make it fire. The rate at which impulses are generated
depends on the intensity of the stimulus -- that is, the rate of energy
transfer. This is true of all sensory endings, although there are
differences in linearity and temporal effects. Once inside the nervous
system all we have are trains of impulses, which are direct functions of
the intensity of stimulation (regardless of the type of stimulation).

The neural signals are _analogs_ of the physical processes outside the
nervous system. At the first level, the only possible analog stands for
intensity. Outside the nervous system we might have a physical variable
like temperature. The magnitude of that temperature is represented inside
the nervous system as a rate of firing of a neural signal: that is what is
meant by "analog". Temperature (actually a temperature difference) is
sensed as a rate of flow of heat energy into or out of the sensory neuron.
That is what "intensity" means. The maqnitude of this flow is represented
as so many impulses per second flowing out of the sensor and out the axon
toward more central structures.

The first-level signals enter second-order perceptual input functions which
are computing networks in the spinal cord and brainstem. Here, I think, the
functions create new signals which are weighted sums of the intensity
signals. These new signals are what I call sensation signals, because
weighted sums of intensities behave like sensations: the same sensation can
come from different first-order receptors, and the maximum of a given kind
of sensation (such as an odor) occurs when different kinds of receptors are
stimulated in certain fixed proportions. Whether your left hand's
temperature sensors are stimulated or those of your right hand, it is the
same sensation, "warmth", that you experience, although no intensity signal
is duplicated. This is consistent with the idea of weighted sums of
intensity signals (perhaps normalized) being experienced as sensations.

What I'm saying here is that intensity signals are _inherently_ first-order
signals, and sensations signals are inherently, physically, related to the
first-order signals in a specific way. Therefore there is no possibility
that these levels of perception (and thus control) could be shuffled around
to different levels, or swapped.

This is how I see the entire hierarchy. Each level's perceptual signals
depend on the perceptual signals from the level below, not for
philosophical reasons or logical reasons but because that is how the wiring
is arranged. While we may conjecture about the nature of the levels and
which are below or above which others, there is only one right answer in a
given person, and perhaps in a given species. Of course individual examples
of perceptions at a given order could differ radically; I'm speaking only
of the way one kind of perception depends on others.

The problems you're dealing with arise when we get to the levels in which
language takes place. Just as in a computer, the structure of the
programming of the brain is infinitely variable, including the possibility
of creating levels upon levels of abstraction, arbitrary and embedded
classifications, logical (and illogical) reasoning, and so forth. No one of
these structures is "right" _a priori_ -- it is merely an example of the
kind of programming that can exist at this level in the physical brain.
Rioghtness is a question for experimental investigation. The structure of
symbolic levels has nothing to do with the levels of perception and control
in the brain, just as the structures of different Nintendo games reveal
nothing about the physical organization of the Nintendo box, which is the
same for all the games. They simply show the kinds of operations a brain
can _do_ -- they reveal the _behavior_ of these levels of the brain, not
its underlying organization.

It's a simple observation that people can control the rate, amplitude, and
phase of repeated space-time patterns. Is there a physical level of the
brain specifically associated with this sort of capability? The only way to
settle that is to model all the levels and show that without this specific
capability, repetitive patterns can't be controlled. Or else to show
neuroanatomically that there is such a level. I think we're rather a long
way from being able to do either demonstration.

Best,

Bill P.

[Bruce_Gregory]

[From Bruce Gregory (981102.1530 EDT)]

Bill Powers (981102.-0725 MST)

It's a simple observation that people can control the rate, amplitude, and
phase of repeated space-time patterns. Is there a physical level of the
brain specifically associated with this sort of capability? The
only way to
settle that is to model all the levels and show that without this specific
capability, repetitive patterns can't be controlled. Or else to show
neuroanatomically that there is such a level. I think we're rather a long
way from being able to do either demonstration.

I'm sure you're right. I appreciate the clear and concise statement of your
view of the hierarchy.

Bruce Gregory