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Posted-Date: Tue, 18 Aug 92 11:09:03 PDT
Newsgroups: bit.listserv.csg-l
Date:         Tue, 18 Aug 1992 11:09:03 PDT
From:         marken@AERO.ORG
Subject:      Re: PCT vs cognitivism

[From Rick Marken (920818)]

First some off the wall comments before I try to answer some of penni
sibum's specific comments.

1. The fascist fandango was too scarry for me; I had to turn it off after
Buchanan's speech. What a sweet, caring, tolerant bunch of what, I
suppose, have to be classed as human beings.

2. Did anyone (such as you, Bruce Nevin) invite that editor from Discover
to listen in on CSGnet?  I think it would be a nice idea to try to get
something published in that forum.

penni sibun (920816) says:

>  i don't think
> cognitivism necessarily sees beh. as the ``end result'' of mental
> processing; i think cognitivism sees mental processing as crucial for
> behavior.

  In the cognitive model I used as an example, a behavior -- a sequence of
finger taps -- is thought to be generated by a hierarchical set of commands.
These commands are generated by a mental plan (that presumably exists in
the brain). As this plan unfolds it generates the appropriate finger sequence
(in theory) The movement of each finger produces the sequences of taps which
is the behavior being accounted for by the model. So the behavior (sequence
of taps) is the end  result of the mental plan. It works like this:

mental plan >> efferent commands >> finger movement>> taps

This is a lineal causal process which I argue is characteristic of ALL
cognitive models. Note that behavior (in this case, the taps) is at the end
of the line.

The problem with this model is that it neglects some important aspects of the
situation -- namely, disturbances. Disturbances are known to enter the
process right after the efferent commands are generated. Efferent
commands are neural impulses that cause muscles to tense; but the amount of
tension per unit efferent signal varies considerably over time; so the result
of efferent  commands is disturbed by variations in the effect of neural
commands on  muscles. Environmental disturbances enter the picture after
muscle tensions occur and influence the effect of these tensions on the
results they are intended to produce. For example, changes in the initial
position of the finger will  influence whether or not a particular amout of
tension will result in a tap or not.

The existence of disturbances means that there is no way for a system to
reliably produce an intended result via the same means (in this case, the
same efferent commands).  This meams that there is no question that
Rosenbaum's sequence production model will not behave as the subjects
do in a real environment (the same environment as the one the subjects work
in).So this type of cognitive model is unquestionably wrong.

The only way that a system can be designed to produce reliable results in a
disturbance prone enviroment is to design the system so that is controls
the perceptual representation of those results; this sort of model is based on
a closed loop organization -- it is a control model.  The important
characteristicof such a model is that is varies its output (efferent commands)
in order to keep the perceptual representation of the result at an internally
specified reference level; it controls its perception. Once you understand
this, then you realize that the process of understanding behavior is not a
matter of learning how systems generate complex sequences of outputs. It is
a matter of learning what aspects of their own perceptual experience are
being controlled. Behavior is organized around the control of perception;
indeed, I would say that behavior IS perception in action  (a slogan, I
know, but one that makes sense when you watch the behavior of a
control hierarchy, especially from the point of view of the control hierarchy
itself). If you think about it, you will realize that your own behavior, from
moving your  fingers to trying to argue the virtues of interactionism, is a
matter of producing the perceptions that you want to produce. In fact, there
is no behavior without perception; I argue that you can't do anything (intent-
ionally) that you cannot perceive (I know that we do a lot without attending;
but how much do you do without perceiving?). I know that there are some cases
where behavior seems to happen without perception; for example, you can
move your leg even though you cannot perceive it because you've slept on it
all night.  But I would argue that what you are controlling is perceptual side
effects produced by throwing the leg around basically; you certainly can't
control the degree of bend real well, if you can't perceive it.

The fact that perception is fundemental to PCT means that people who have
always been students of perception (like myself) have a whole new level
of justification for their interest. The study of perception is no longer
just an arcane little sidelight to understanding behavior; it's what behavior
is all about. So it is strange to me to hear you say:

penni sibun (920817)

  >there's just tons of literature on
>perception that suggest that perc. is a *lot* of work; in fact it
> involves action--perhaps to the degree that p. and a. are inseparable.
(``active vision'' is a current buzzphrase.)

All the literature in the world won't convince me that I'm working hard as I
glance around and perceive different aspects of the world (my neural
networks may be computing some very complex functions of my sensory
inputs, but it feels pretty effortless). There's different levels of bright-
ness, lots of colors and sounds, patterns, objects (here's a computer screen,
there's a bunch of books), relationships (I'm closer to the computer than to
the door), events (the secretary just when to the other office), sequences.
I can even perceive principles and system concepts with little effort (I was
perceiving some pretty ugly ones last night, that's for sure -- though, of
course, they were only ugly relative to my own references; the people at the
convention seemed to think they were perceiving great principles).

While it takes no effort to perceive, it can take substantial effort to con-
trol those perceptions (get them to the level you want). If I want to perceive
that  big book over here rather than over there I'm going to have to exert
some energy to change that perception. Controlling principles and system
concpets can require some real heavy duty effort; but perceiving the
principle or system concept seem seffortless to me.

I have to imagine that active vision is controlled visual variables--
and it seems to be from your examples (like squinting to reduce glare).
Maybe these active vision people are, indeed, doing PCT.

Anyway, back to controlling other perceptions.

Regards

Rick


     **************************************************************

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)
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