Leading Questions - Chapter 3

[From Bill Powers (990105.1416 MST)]

Fred Nickols (981227.1350 EST)--

I think I got lost in the time integration/differentiation
explanation but I don't know how critical that is.

It's of interest to modelers, as is most of this chapter. You've done well
in summarizing it, so these details can't be very important!

So, on to the Leading Questions for Chapter 4.

1. How many brief, abrupt stimuli have you experienced in
the past ten minutes? Were you aware during that time of
any continuous stimuli?

I don't recall experiencing any brief, abrupt stimuli.

That's pretty much what I expected.

2. How many brief, abrupt responses have you made in the
last ten minutes?

Now, fast-forward to right now, as I
key this message. Striking the keys might fit the defintion
of "brief and abrupt."

OK. We don't _rule out_ brief, abrupt stimuli. But they're not the most
common case.

3. When you steer a car around a curve, do you make a
steering movement, wait to see the result, make another
movement, wait to see the result and so forth? Or does it
seem that the steering motions and their results vary
smoothly and continuously during the same time interval?

To the first question, No. To the second question, Yes.

Me, too.

4. Does a continuous-variable model rule out perception
of brief, abrupt events? execution of brief, abrupt responses?
instantaneous responses?

My brief, abrupt, instantaneous responses are no, no and no.

I'll dispute the third. Is there any kind of change in nature that takes
literally NO time to occur? That's what "instantaneous" means to me.

Best,

Bill P.

[From Fred Nickols (990106.2002)]--

Bill Powers (990105.1416 MST)]

Fred Nickols (981227.1350 EST)--

4. Does a continuous-variable model rule out perception
of brief, abrupt events? execution of brief, abrupt responses?
instantaneous responses?

My brief, abrupt, instantaneous responses are no, no and no.

Bill P...
I'll dispute the third. Is there any kind of change in nature that takes
literally NO time to occur? That's what "instantaneous" means to me.

Okay; I get it. I thought I was saying there is no such
thing as an instantaneous response but I wasn't.

Regards,

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

[From Fred Nickols (981227.1350 EST)]--

Ow! This one made my head hurt.

Chapter 1 was about the Dilemmas of Behaviorism, Chapter 2
was about Models and Generalizations, and Chapter 3 is about
Premises. (No, mixing up tenses has never bothered me.)

I noted five sets of premises in all: Digital, Analogue,
Neural Analogue, Perception, and Brain Organization.

A choice is made early in the chapter in favor of Analogue
over Digital. A second choice is quickly made in favor of
neural current as the basic measure of nervous system
activity.

Brief reference is made to the sixth, seventh and eighth
levels before launching into a discussion of a model of
neural conduction, which shows how various neural net
configurations can perform all the algebraic functions
necessary to analogue computing. Key points made here
include:

  Negative sign means 0, not a negative number.
  Sign (+ or -) does not mean flow.
  Sign means excitatory or inhibitory.
  No conservation law required; current is equal in all
        branches.
  Branches thus serve as amplifiers or multipliers.
  Multiplication = 2 excitatory; division = 1 excitatory
        and 1 inhibitory.

I think I got lost in the time integration/differentiation
explanation but I don't know how critical that is. I did
follow the explanation but I don't quite see the connection
to time. Maybe I don't know what is meant by integration
and differentiation in relation to time (although it sounds
a lot like those calculus equations in the old fire control
problem that were essential to determining rate of climb and
dive, etc--but then I never understood those either...)

On page 33, following the discussion of the differentiator,
the comment is made in relation to Figure 3.9: "The added
design required to make a complete differentiator is left
as an exercise for the reader, being fairly obvious." Well,
it ain't obvious to this reader...

KEY POINT: Distinction drawn between perception (as neural
current) and "conscious perception" or awareness.

"Thus many perceptions may be involved in behavior even
though the subject is not always paying attention to them."
(p.35)

"Perception" defined as "a neural current in a single fiber
or bundle of redundant fibers which has a magnitude that is
related to the magnitudes of some set of primary sensory-
nerve stimulations." (p.35)

First-order perceptions are of intensity. Stimulation is
continuous, not discrete. (Hmm. This clearly implies that
slicing out some aspect of our experienced environment and
calling that a "stimulus" is a wee bit arbitrary.)

On page 37 I found an idea that really tickled my fancy:
I've restated it as follows: "The taste of lemonade is
not in the lemonade." This fits well with something I'll
quote verbatim from page 37:

        "We may strongly suspect that there is a real
        universe out there, beginning a millimeter outside
        of our nervous systems, but our perceptions are not
        that universe. They depend on it, but the form of
        that dependence is determined in the brain, by the
        neural computers which create perceptual signals
        layer by layer through transformations of one set
        of neural currents into another."

On page 39, in the Summary, the purpose of making my head
hurt through the earlier parts of Chapter 3 is stated as
follows: "...to show that there is a defensible alternative
to the strict digital-computer model of the brain that has
been so popular for several decades."

Okay, I'll buy that. As I wrote in my systems poem shortly
after reading B:CP the first time (way back in 1975):

        "But stand well clear of the digital view; it doesn't
        fit me, it doesn't fit you."

So, on to the Leading Questions for Chapter 4.

1. How many brief, abrupt stimuli have you experienced in
the past ten minutes? Were you aware during that time of
any continuous stimuli?

I answered these questions while sitting at my desk, after
finished Chapter 3 so the ten minutes above refers to the
last ten minutes of reading Chapter 3.

I don't recall experiencing any brief, abrupt stimuli. I
do recall being intermittently aware of background noise;
for example, music from the stero came and went, as did the
sounds of the nib of my pen moving across the paper. But
no one came up and poked me or spoke to me and the roof
didn't cave in either. On the continous side of things, I
was aware most of the time of the pressure on the bottom
side of my buttocks and thighs, the consequence of 200 lbs
loaded on to frame designed to carry 165 lbs. Reflection
suggests that the mild ache in the forefinger of my right
hand results from pressing the pen too firmly; it also
reveals that I was blissfully unaware of countless other
stimuli necessary to perform the act of writing (e.g., my
forearm resting on the desk top).

2. How many brief, abrupt responses have you made in the
last ten minutes?

Originally, I wrote, "It depends on your meaning of brief
and abrupt. Jotting down my notes could be termed brief
and abrupt in that anyone observing might have observed a
sequence something like 1) picked up pen, 2) made some
marks on the paper, 3) put pen down. But the briefness
and abruptness of these are the result of arbitrary lines
of demarcation made in what is, for me and to me, a smooth,
flowing experience. Now, fast-forward to right now, as I
key this message. Striking the keys might fit the defintion
of "brief and abrupt."

3. When you steer a car around a curve, do you make a
steering movement, wait to see the result, make another
movement, wait to see the result and so forth? Or does it
seem that the steering motions and their results vary
smoothly and continuously during the same time interval?

To the first question, No. To the second question, Yes.

As an aside, I'm going to have some fun with this example.

4. Does a continuous-variable model rule out perception
of brief, abrupt events? execution of brief, abrupt responses?
instantaneous responses?

My brief, abrupt, instantaneous responses are no, no and no.
But then I won't be surprised if I'm wrong in terms of the
model; after all, everything is related to everything else at
all times, isn't it? I think words like "brief," "abrupt" and
"instantaneous" are labels we use to describe perceptions or
experiences of events. It's kind of like the point of
inflection on the infamous Bell Curve; it can be calculated
but I defy you to put your finger on it--precisely. (Well,
okay, your fingertip will no doubt cover it and thus be on
it in a technical sense.)

See, I told you Chapter 3 made my head hurt...

···

--

Regards,

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