INTROCSG.NET

INTROCSG.NET

This file is posted every month to CSGnet.

       INTRODUCTION TO PERCEPTUAL CONTROL THEORY (PCT)
               THE CONTROL SYSTEMS GROUP (CSG)
        AND THE CONTROL SYSTEMS GROUP NETWORK (CSGnet)

          Prepared by Dag Forssell with Gary Cziko
                  Updated January 1, 1997

This is an introduction to Perceptual Control Theory (PCT), and
the discussion group CSGnet. CSGnet is listed on Usenet as the
newsgroup "bit.sci.purposive-behavior." This introduction is
posted at the beginning of each month for newcomers to CSGnet and
the newsgroup.

A complementary "PCT Introduction and Resource Guide" is available
from the WWW server shown below (Resource.pct). It features the
original book jacket for Bill Powers' seminal 1973 book _Behavior:
The Control of Perception_; two short essays: _An essay on the
obvious_ and _Things I'd like to say if they wouldn't think I am a
nut_, which deal with the requirements for and consequences of
applying physical science to the field of psychology; the foreword
for _Living Control Systems II_ by Tom Bourbon and more; plus more
detailed descriptions of PCT books, videos, articles, sources,
etc.

Contents:

   Introductions to Perceptual Control Theory
   The Evolution of the Control Paradigm
   Demonstrating the Phenomenon of Control
   The Purpose of CSGnet
   CSGnet Participants
   Asking Questions
   Post Format
   The Control Systems Group
   Accessing and Subscribing to CSGnet
   World-Wide Web
   On-line documents
   References

  INTRODUCTIONS TO PERCEPTUAL CONTROL THEORY

  STANDING AT THE CROSSROADS

            Distributed at the Control Systems Group Meeting,
            August 15-19,1990, at Indiana, Pennsylvania.

  By William T. Powers.
           [Comments by Dag Forssell, Jan 1, 1997]

  I'd like to try today to give you the sense that psychology is
  standing at a crossroads -- and not only psychology, but all the
  sciences of life. We are about to experience the advent of
  something for which many people have searched, an organizing
  scheme that pulls together all the disparate schools of thought,
  specializations, movements, and evanescent fads that make up
  various fragmented branches of the life sciences.

  The organizing scheme is called "Perceptual* Control Theory."
  This theory explains a phenomenon, as theories are supposed to
  do. The phenomenon in question is called control. Everyone has
  heard this word, and most people have occasion to use it from
  time to time, but in science it has become part of the
  metalanguage rather than designating a subject of study. A
  scientist does a control experiment, or demonstrates how
  manipulation of stimuli and rewards can control an animal's
  movements, or advocates a proper diet to control cholesterol
  level or competes for control of a department. This word is used
  as part of a background of ordinary language, but it has not
  been part of the technical language of the life sciences.

     [* The word Perceptual was added at a later conference to
     distinguish Bill Power's creation from competing, non-
     functional interpretations by other authors. This term is
     technically more precise, since all control systems actually
     control their perceptions, not their outputs.]

  The reason is quite simple: nobody in or out of science
  understood the process of control until about the beginning of
  World War 2. By understanding the process, I mean being able to
  define it, characterize it, measure its parameters, predict how
  it will proceed, and recognize it in a real system. This doesn't
  mean that control was impossible to accomplish before World War
  2: after all, most people accomplish digestion without
  understanding any biochemistry. But control is as natural a
  process as digestion, and like digestion can be understood in a
  scientific way only by studying it and learning how it works.

  World War 2 started only about 50 years ago. Perhaps you can see
  why this fact implies some problems with studying control as a
  natural process. If control is a natural process, it was
  occurring in 1840, 1740, 1640, and so on back to the primordial
  ooze. In 1940, the sciences of life were already something like
  300 years old (and their prehistory was far older than that). If
  nobody understood control until 1940, it's clear that these
  sciences went through a major part of their development without
  taking it into account. The next question is obvious: how did
  they explain the phenomena that arise from processes of control?

  Many of the puzzles and controversies that occupied early
  researchers could have been resolved if scientists had realized
  that they were dealing with control processes. Purpose could
  have been studied scientifically instead of merely
  theologically. We can see now that all these early researchers,
  not recognizing a control process when they saw one, were
  drastically misled by some side-effects of control. The
  principal side-effect that deceived them resulted from the way
  control systems act in the presence of disturbances of the
  variables they control. When a disturbance occurs, a control
  system acts automatically to oppose the incipient change in the
  controlled variable. But if this opposition is not recognized
  (it's not always obvious), the observer will inevitably be led
  to see the cause of the disturbance as a stimulus and the action
  opposing its effects as a response to the stimulus. Furthermore,
  this opposition results in stabilizing some aspect of the
  environment or organism- environment relationship. That
  stabilization conceals the role of the stabilized variable in
  behavior; the better the control, the lower will be the
  correlation between the controlled variable and the actions that
  stabilize it. The variable under control is the one that is
  actually being sensed, but the logic of control makes it seem
  that the disturbance is the sensory stimulus.

  Donald T. Campbell [Late Professor of Psychology, Lehigh
  University] has proposed a "fish-scale" metaphor of scientific
  progress. Each worker constructs just one small scale that
  overlaps those already laid down by others. Eventually the whole
  fish will be covered completely. But what if the fish is a red
  herring? Then all these patient workers will devote their lives
  to covering the wrong fish. The converse of the fish-scale
  metaphor is that a person who is concentrating on fitting one
  little scale to others already laid down is bound to have a very
  localized view of the problem. Seeking to extend the
  accomplishments of others, a single worker can make what seems
  to be progress -- but it is unlikely that a single worker will
  discover that something is wrong with the whole design. The
  result can easily be the diligent application of fish-scales to
  a giraffe.

  I submit that something like this has happened in the life
  sciences. A fundamental misconception of the nature of behavior,
  natural but nevertheless horrendous, has pointed the life
  sciences down the wrong trail. Nearly all life scientists,
  particularly those who try to achieve objectivity and uniform
  methodology, have interpreted behavior as if it were caused by
  events outside an organism acting on a mechanism that merely
  responds. This hypothesis has become so ingrained that it is
  considered to be a basic philosophical principle of science. To
  explain behavior, one varies independent variables and records
  the ensuing actions; to analyze the data, one assumes a causal
  link from independent to dependent variable and calculates a
  correlation or computes a transfer function. This leads in turn
  to models of behaving systems in which inputs are transformed by
  hypothetical processes into motor outputs; those models lead to
  explorations of inner processes (as in neurology and
  biochemistry) predicated on the assumption that one is looking
  for links in an input-output chain. One assumption leads to the
  next until a whole structure has been built up, one that governs
  our thinking at every level of analysis from the genetic to the
  cognitive.

  Perceptual control theory, by showing us an alternative way of
  understanding this entire structure, therefore threatens the
  integrity of practically every bit of knowledge about behavior
  that has ever been set down on paper.

  This is, of course, a message of the type that leads to a high
  mortality among messengers. That is why you are listening to a
  person with no reputation to lose and no fame to protect,
  instead of a Nobel Prize winner. In an utterly predictable way,
  scientists have for the last 50 years gone to great lengths to
  avoid learning control theory or else to assimilate it into the
  existing picture of behavior. Failing that, they have simply
  declared it irrelevant to their own fields, with the result that
  the authoritative literature of perceptual control theory is
  almost completely insulated from the mainstream. It appears in
  publications like proceedings of the Institute of Electrical
  Engineers division on Man, Machines, and Cybernetics, or in
  human factors and manual control publications, or in Xeroxed
  papers passed from hand to hand. There is a scattered literature
  on perceptual control theory in the life sciences, but nothing
  on this subject gets past the referees into a standard journal
  without first having its teeth pulled.

  Despite all the defenses, the concepts of perceptual control
  theory are spreading. When our descendants look back on the
  latter half of the 20th Century, they will probably be amazed
  at the speed with which perceptual control theory became
  accepted: 50 years in the course of a science is nothing. We
  control theorists have nothing to complain about. Our greatest
  successes have come not through pounding at locked doors, but
  through continuing to explore the meaning of this new approach
  and learning how to apply it in many different disciplines. If
  we do our job correctly, acceptance will take care of itself.
  That job is not something one can toss off overnight, nor can it
  be done by just a handful of people. We are coming to a time of
  rigorous re-evaluation of all that is known or presumed to be
  known about the nature of organisms. The more people that are
  involved in this enormous project, the sooner it will be
  accomplished. That is why we are all so glad to welcome our
  guests at this session: after the party, you will be invited to
  help do the dishes.

  There has been progress in understanding how organisms work, the
  wrong model notwithstanding. Biochemical reactions are not going
  to change because of perceptual control theory. Muscles and
  nerves will continue to operate as they are known to operate.
  Even at more abstract levels of analysis, many phenomena will
  continue to be accepted as valid observations; for example,
  phenomena of perception, of memory, of cognition. If competently
  observed, these phenomena will still be part of the legacy of
  earlier workers. When we pull the stopper on the old theories,
  we must keep a strainer over the drain and let only the bath
  water out.

  Part of the task of reconstructing the sciences of life consists
  of separating valid observations of components from invalid
  conjectures about how they work together. Consider biochemistry
  as an example. Biochemistry is an odd mixture of solid research
  and wild leaps of undisciplined imagination. The research
  reveals chemical processes taking place in the microstructure of
  the body. The wild leaps propose that the chemical reactions
  somehow directly produce the behavioral effects with which they
  are associated. It's as though a specialist in solid-state
  physics were to propose that electrons flowing through wires and
  transistors are responsible for the music that comes out of a
  radio. While it's true that a shortage of electrons will make
  the music faint, and that without the electrons you wouldn't get
  any music, the physicist would be laughed out of town for
  suggesting that electrons cause music, or that you could fix a
  weak radio just by putting some more electrons into it. You
  can't understand the role of the electrons without grasping the
  principles of organization that make the radio different from a
  radio kit.

  In the same way, if shortages or excesses of chemicals like
  enzymes and neurotransmitters are found to be associated with
  functional and behavioral disorders, all we then know is that
  these substances play some role in the operation of the whole
  system that creates organized behavior. If there's a shortage of
  some chemical substance, then some other system has reduced its
  production of that substance, and some other system still has
  decreased its effect on the driving system, and so on in chains
  and causal loops. Nothing in a system as complex as the human
  body happens in isolation. If biochemistry is to have anything
  to say about the organism at any higher level, biochemists are
  going to have to study whole systems, not isolated reactions. We
  need a functional theory to supplement the microscopic laws of
  chemistry.

  There are workers in biochemistry who are investigating feedback
  control processes. One significant process involves an
  allosteric enzyme that is converted into an active form by the
  effect of one substance, and into an inactive form by the effect
  of another. When these two substances have the same
  concentration, the transition from active to inactive is
  balanced; the slightest imbalance of the substances causes a
  highly amplified offset toward the active or the inactive form.
  In one example, the active form catalyzes a main reaction, and
  the product of that reaction in turn enhances the substance that
  converts the enzyme to the inactive form -- a closed-loop
  relationship. The feedback is negative, because the active form
  of enzyme promotes effects that lead to a strong shift toward
  the inactive form. This little system very actively and
  accurately forces the concentration of the product of the main
  reaction to match the concentration of another substance, the
  one that biases the enzyme toward the active form. This allows
  one chemical system to control the effects that another one is
  having on the chemical environment.

  A person without some training in recognizing control processes
  might easily miss the fact that one chemical concentration is
  accurately controlling the product of a different reaction not
  directly related to the controlling substance. The effect of
  this control system is to create a relationship among
  concentrations that is imposed by organization, not simply by
  chemical laws. This is the kind of observation that a
  reductionist is likely to overlook; reductionism generally means
  failing to see the forest for the trees. Even the workers who
  described this control system mislabeled what it is doing --
  they concluded that this system controls the outflow of the
  product, when in fact it controls the concentration and makes it
  dependent on a different and chemically-unrelated substance.

  To shift through several gears, consider the lines of research
  that began with Rosenblatt's perceptron. This device was
  conceived as a behavioral system that could be trained to react
  to patterns contained in its input information. First this idea
  was shown, by something of a hatchet job, to be impractical, and
  then it was shown to be practical again if several levels of
  training could occur within it (I haven't seen any apologies to
  Frank Rosenblatt, who died without vindication). In all its
  incarnations, however, the perceptron has been thought of as a
  system that learns to "respond correctly" to a stimulus pattern.

  From the standpoint of perceptual control theory, however,
  organisms do not respond to stimuli but control input variables.
  So does that invalidate all that has been learned about
  perceptrons? Not at all. Perceptual control-theoretic models
  desperately need something like a perceptron to explain how
  abstract variables can be perceived. In a perceptual control
  model, however, the perceptron is only one component: it
  provides a signal that represents an aspect of some external
  state of affairs. It's easy to show that behavior can't be
  explained simply by converting such a signal into an output
  action. But behavior can be based on the difference between the
  perceptron's output signal and a reference signal that specifies
  the state of the perception that is to be brought about. The
  control-system model shows where the functions that are modeled
  as perceptrons belong in a model of the whole system.

  Shifting gears again: some theorists are trying to model motor
  behavior in terms of "motor programs" and "coordinative
  structures." In these models, command signals are presumed to be
  computed such that when applied to elastic muscles they produce
  the movements of a real limb. These models contain some
  impressive mathematics, taking into account the linkages of the
  limb and the dynamics of movement of the limb masses. But
  perceptual control theory says that behavior is not produced by
  computing output; it is produced by comparing inputs with
  desired inputs, and using the difference to drive output. No
  complicated "motor program" computer is needed. Does this mean
  that the mathematical analysis by the motor program people is
  spurious and ought to be discarded?

  Again, not at all. At some point in elaborating the perceptual
  control model, we must show how the driving signals actuate
  muscles to cause the movements we actually see. This entails
  solving all the physical equations for muscle and limb dynamics,
  just as the motor programmers have done. If they did their
  arithmetic right, it will still be right when we substitute the
  perceptual control-system model for the central-computer model.
  Both models have to produce the same driving signals. The only
  thing that will change is that perceptual control theory will
  show how the required driving signals arise naturally from
  perception and comparison against reference signals, instead of
  being computed blindly from scratch.

  Finally, shifting to overdrive, what do we do about Artificial
  Intelligence? We take advantage of whatever it really has to
  offer, modifying it only where we know it fails to explain
  enough. One place where it fails to explain enough is in the way
  it deals with action. Basically, it doesn't deal with action. It
  starts its analysis with perception of abstract variables in the
  form of symbols, constructs models that imitate human symbol-
  handling processes as well as possible, and finishes by
  generating more strings of symbols that describe actions to be
  taken. It says nothing useful about how a description of an
  action, in symbols, gets turned into just those muscle tensions
  that will in fact produce an action that fits the description.
  When devices are built that are run by symbol-processing
  computers, the critical transformations that make action out of
  symbols are simply put into the device by its builders. Many of
  those critical parts turn out to be servomechanisms --
  perceptual control systems.

  The assimilation of perceptual control theory into the life
  sciences will require a lot of this kind of reanalysis. Some old
  ideas will have to go, some will stay. This job is best done by
  people who are already competent in existing fields. Of course
  these also have to be people who can see that there is room for
  improvement along lines other than the standard ones.

  In the current membership of the Control Systems Group we have
  representatives of at least a dozen disciplines of the life
  sciences, and a few persons representing some unlikely
  occupations such as piano teaching and law. When these people
  meet, there is little difficulty in communicating because all of
  them have a basic understanding of perceptual control theory.
  But communication isn't the only factor that makes these
  meetings valuable. The most important lesson comes from seeing
  how perceptual control theory applies in someone else's field.

  The biggest problem with introducing perceptual control theory
  to scientists in conventional disciplines is that each scientist
  tends to think only of the scientific problems that are defined
  in that one field. The problem in question may involve behavior,
  but behavior is generally taken on faith to work the way some
  other specialist says it works. In fact most scientists tend to
  dismiss details involving other fields, assuming (often quite
  wrongly) that somebody else understands them well enough. We
  therefore find some very detailed biochemistry or neurology or
  personality- testing, all done competently, being used to
  explain behavioral phenomena that are very poorly analyzed and
  in many cases don't actually occur. The sociobiologist concludes
  that behavior patterns are inherited, not knowing that only the
  consequences of motor outputs, not the outputs themselves,
  repeat. What does a geneticist really know about the actions
  through which a bird catches a bug? You can inherit the
  perceptual control systems that are capable of catching bugs,
  but you can't inherit acts that happen to take you where a
  particular bug is going next. The combination of narrow
  expertise in one field and naive conceptions in every other
  field leads to facile explanations that are right only at one
  point.

  Specialists must see the need for a model of behavior that
  applies in all disciplines, even those in which the specialist
  is not competent. Once the Artificial Intelligence researcher
  understands exactly why organized behavior cannot be produced by
  computing outputs, he or she will modify the AI model so it will
  work correctly with more detailed systems actually capable of
  organized behavior. Important effects of learning how perceptual
  control theory applies in other fields will occur at the
  boundaries between disciplines -- exactly where we need to work
  if we are ever to have a unified science of life. At Control
  Systems Group meetings, specialists from many fields hear other
  specialists talking about the way perceptual control theory has
  made them rethink the problems in a different field. Because of
  the common understanding, this inevitably reveals one's own
  hasty assumptions, and encourages still more rethinking.

  One last remark about the CSG. The CSG does not represent any
  one scientific discipline. It has no agenda of its own beyond
  encouraging the application of perceptual control theory within
  existing disciplines -- no agenda, that is, except perhaps
  lowering the barriers between disciplines. The psychologists in
  the group are still psychologists, the sociologists are still
  sociologists, the therapists are still therapists, the engineers
  still engineers. This is not a political movement nor an
  alternative to established science. It is simply a vehicle for
  promoting interaction among people interested in using or
  learning more about perceptual control theory in any specialty
  whatsoever. When all the branches of the life sciences have
  assimilated and begun using perceptual control theory, the CSG,
  its work accomplished, will have no further reason to exist.

  In this presentation I have talked around perceptual control
  theory, alluding to some of its conclusions without attempting
  to justify or explain them. Learning perceptual control theory
  can't be done by listening to a half-hour's talk. I hope that
  some of you will find the promise of a unifying principle for
  the life sciences appealing enough to go further into this
  subject.

  * * * * * * * *

  Mary Powers, November 1992:

  While the existence of control mechanisms and processes (such as
  feedback) in living systems is generally recognized, the
  implications of control organization go far beyond what is
  generally accepted. We believe that a fundamental characteristic
  of organisms is their ability to control; that they are, in
  fact, living control systems. To distinguish this approach from
  others using some version of control theory but forcing it to
  fit conventional approaches, we call ours Perceptual Control
  Theory, or PCT.

  PCT requires a major shift in thinking from the traditional
  approach: that what is controlled is not behavior, but
  perception. Modelling behavior as a dependent variable, as a
  response to stimuli, provides no explanation for the phenomenon
  of achieving consistent ends through varying means, and requires
  an extensive use of statistics to achieve modest (to the point
  of meaningless) correlations. Attempts to model behavior as
  planned and computed output can be demonstrated to require
  levels of precise calculation that are unobtainable in a
  physical system, and impossible in a real environment that is
  changing from one moment to the next. The PCT model views
  behavior as the means by which a perceived state of affairs is
  brought to and maintained at a reference state. This approach
  provides a physically plausible explanation for the consistency
  of outcomes and the variability of means.

  The PCT model has been used to simulate phenomena as diverse as
  bacterial chemotaxis, tracking a target, and behavior in crowds.
  In its elaborated form, a hierarchy of perceptual control
  systems (HPCT), it has lent itself to a computer simulation of
  tracking, including learning to track, and to new approaches to
  education, management, and psychotherapy.

  Control systems are not new in the life sciences. However,
  numerous misapprehensions exist, passed down from what was
  learned about control theory by non-engineers 40 or 50 years ago
  without further reference to newer developments or correction of
  initial misunderstandings. References in the literature to the
  desirability of positive feedback and the assertion that systems
  with feedback are slower than S-R systems are simply false, and
  concerns about stability are unfounded.

  The primary barrier to the adoption of PCT concepts is the
  belief--or hope--that control theory can simply be absorbed into
  the mainstream life sciences without disturbing the status quo.
  It is very hard to believe that one's training and life work,
  and that of one's mentors, and their mentors, must be
  fundamentally revised. Therefore, PCT appeals to those who feel
  some dissatisfaction with the status quo, or who are attracted
  to the idea of a generative model with broad application
  throughout the life sciences (plus AI and robotics). There are
  very few people working in PCT research. Much of its promise is
  still simply promise, and it meets resistance from all sides. It
  is frustrating but also tremendously exciting to be a part of
  the group who believe that they are participating in the birth
  of a true science of life.

                 * * * * * * * *

  THE EVOLUTION OF THE CONTROL PARADIGM

The PCT paradigm originates in 1927, when an engineer named Harold
Black completed the technical analysis of closed loop control
systems. He was working with the negative feedback amplifier,
which is a control device. This led to a new engineering
discipline and the development of many purposeful machines.
Purposeful machines have built-in intent to achieve specified ends
by variable means under changing conditions.

The explanation for the phenomenon of control is the first
alternative to the linear cause-effect perspective ever proposed
in any science.

The first discussion of purposeful machines and people came in
1943 in a paper called: Behavior, Purpose and Teleology by
Rosenblueth, Wiener and Bigelow. This paper also argued that
purpose belongs in science as a real phenomenon in the present.
Purpose does not mean that somehow the future influences the
present.

William T. (Bill) Powers developed PCT, beginning in the mid-50's.
In 1973 his book called "Behavior: the Control of Perception."
(often referred to as B:CP) was published. It is still the major
reference for PCT and discussion on CSGnet.

B:CP spells out a suggestion for a working model of how the human
brain and nervous system works. Our brain is a system that
controls its own perceptions. This view suggests explanations for
many previously mysterious aspects of how people interact with
their world.

Perceptual Control Theory has been accepted by independently
thinking psychologists, scientists, engineers and others. The
result is that an association has been formed (the Control System
Group), several books published, this CSGnet set up and that
several professors teach PCT in American universities today.

  DEMONSTRATING THE PHENOMENON OF CONTROL

Few scientists recognize or understand the phenomenon of control.
It is not well understood in important aspects even by many
control engineers. Yet the phenomenon of control, when it is
recognized and understood, provides a powerful enhancement to
scientific perspectives.

It is essential to recognize that control exists and deserves an
explanation before any of the discourse on CSGnet will make sense.

Please download the introductory computer demonstrations,
simulations and tutorials, beginning with "demo1". See "World-Wide
Web" below for obtaining files via FTP and WWW.

  THE PURPOSE OF CSGnet

CSGnet provides a forum for development, use and testing of PCT.

  CSGnet PARTICIPANTS

Many interests and backgrounds are represented here. Psychology,
Sociology, Linguistics, Artificial Intelligence, Robotics, Social
Work, Neurology, Modeling and Testing. All are represented and
discussed. As of March 20, 1995 there were 146 individuals from 20
countries subscribed to CSGnet.

  ASKING QUESTIONS

Please introduce yourself with a statement of your professional
interests and background. It will help someone answer if you spell
out which demonstrations, introductory papers and references you
have taken the time to digest.

  POST FORMAT

When you are ready to introduce yourself and post to CSGnet,
please begin each post with your name and date of posting at the
beginning of the message itself, as shown here:

[From Dag Forssell (970212 1600)]

This lets readers know who sent the message, and when (sometimes
very different from the automated datestamp). It provides a
convenient reference for replies. When you respond to a message,
please use this reference (remove the word "From"), and quote only
relevant parts of the message you comment on.

  THE CONTROL SYSTEMS GROUP

The CSG is an organization of people in the behavioral, social,
and life sciences who see the potential in PCT for increased
understanding in their own fields and for the unification of
diverse and fragmented specialties.

Annual dues are $20 for full members and $5 for students.

The Thirteenth North American Annual Meeting of the CSG will held
in Durango, Colorado, from July 30 to August 3, 1997. There will
be seven plenary meetings (mornings and evenings), with
afternoons, mealtimes, and late night free for further discussion
or recreation. Full details will be available on CSGnet or by mail
after April 1, 1997.

For membership information write:
CSG, c/o Mary Powers, 73 Ridge Place CR 510, Durango, CO
81301-8136 USA or send e-mail to powers_w@FRONTIER.NET.

  ACCESSING AND SUBSCRIBING TO CSGnet

CSGnet can also be accessed via Usenet where it is listed as the
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the network manager, at g-cziko@uiuc.edu

  WORLD-WIDE WEB

A number of documents (including a hypertext version of this one)
and MS-DOS and MacIntosh computer programs can be obtained via FTP
(ftp://lynx.ed.uiuc.edu/LRS2/CSG/Computer_Programs/) and the
World-Wide Web (http://www.ed.uiuc.edu/csg/).

  ON-LINE DOCUMENTS

A large collection of extracts from CSGnet discussions can be
found at on the World Wide Web at
http://www.ed.uiuc.edu/csg/documents/docindex.html. In addition,
extracts from selected published works can be found among the
references listed below.

  REFERENCES

Here are some selected books, papers and computer programs on
Perceptual Control Theory. For a very complete list of CSG-related
publications, get the file biblio.pct from the fileserver as
described above. See also the "PCT Introduction and Resource
Guide."

                 * * * * * * * *

Bourbon, WT, KE Copeland, VR Dyer, WK Harman & BL Mosely (1990).
On the accuracy and reliability of predictions by control-system
theory. Perceptual and Motor Skills, vol 71, 1990, 1331-1338.
  The first of a 20-year series demonstrating the long-term
  reliability and stability of predictions generated by the PCT
  model.

Bourbon, W. Tom (In Press). Perceptual Control Theory. In: HL
Roitblat & J-A Meyer (eds.). Comparative approaches to cognitive
science. Cambridge, MA: MIT Press.
  Chapter surveys applications of PCT modeling by Bill Powers and
  Greg Williams (pointing, from the ARM/LITTLE MAN program); by
  Rick Marken and Bill Powers (movement "up a gradient" by E.
  coli), by Bill Powers, Clark Mcphail and Chuck Tucker (social
  movement and static formations, from the GATHERINGS program),
  and by Bourbon (tracking). The PCT model is contrasted with some
  of the mainstream models and theories presented at the workshop.

Cziko, Gary A. (1992). Purposeful behavior as the control of
perception: Implications for educational research. Educational
Researcher, 21(9), 10-18, 27.
  Introduction to PCT and implications for educational research.

Cziko, Gary A. (1992). Perceptual control theory: One threat to
educational research not (yet?) faced by Amundson, Serlin, and
Lehrer. Educational Researcher, 21(9), 25-27.
  Response to critics of previous article.

Cziko, Gary. (1995). Without miracles: Universal selection theory
and the second Darwinian evolution. Cambridge: MIT Press/A
Bradford Book.
     See Chap 8, "Adapted Behavior as the Control of Perception"

Ford, Edward E. (1989). Freedom From Stress. Scottsdale AZ: Brandt
Publishing. A self-help book.
  PCT in a counseling framework.

Ford, Edward E. (1987). Love Guaranteed; A Better Marriage In 8
Weeks. Scottsdale AZ: Brandt Publishing.

Ford, Edward E. (1994). Discipline for Home and School. Scottsdale
AZ: Brandt Publishing.
  Teaches school personnel and parents how to deal effectively
  with children.

Ford, Edward E. (1996). Discipline for Home and School, Book Two;
Program Standards for Schools. Scottsdale AZ: Brandt Publishing.
  Additional information focusing on the requirements for
  successful implementation.

Forssell, Dag C., (1994). Management and Leadership: Insight for
Effective Practice.
  A collection of articles and working papers in book form
  introducing and applying PCT in the context of business and
  industry.

Forssell, Dag C. (Ed.), (1995). PCTdemos and PCTtexts. Two DOS
disks 1.44 MB 3 1/2". May be freely copied. Also available at the
WWW site shown above.
  PCTdemos holds eight different tutorial, simulation and
  demonstration programs with documentation. PCTtexts holds 3+ MB
  of essays, explanation, and debate.

Gibbons, Hugh. (1990). The Death of Jeffrey Stapleton: Exploring
the Way Lawyers Think. Concord, NH: Franklin Pierce Law Center.
  A text for law students using control theory.

Hershberger, Wayne. (Ed.). (1989). Volitional Action: Conation and
Control (Advances in Psychology No. 62). NY: North-Holland.
  16 of 25 articles on or about PCT.

Judd, Joel. (1992). Second Language Acquisition as the Control of
Nonprimary Linguistic Perception: A Critique of Research and
Theory. Unpublished doctoral dissertation, University of Illinois
at Champaign-Urbana. Dissertation Abstracts International, 53,
(7), #9236495.

Marken, Richard S. (Ed.). (1990). Purposeful Behavior: The control
theory approach. American Behavioral Scientist, 34(1). (Thousand
Oaks, CA: Sage Publications).
  11 articles on control theory.

Marken, Richard S. (1992). Mind Readings: Experimental Studies of
Purpose. NC: New View.
  Research papers exploring control.

McClelland, Kent. 1994. Perceptual Control and Social Power.
Sociological Perspectives 37(4):461-496.

McClelland, Kent. On Cooperatively Controlled Perceptions and
Social order. Available from the author, Dept. of Sociology,
Grinnell College, Grinnell IOWA 50112 USA.

McPhail, Clark. (1990). The Myth of the Madding Crowd. New York:
Aldine de Gruyter.
  Introduces control theory to explain group behavior.

McPhail, Clark., Powers, William T., & Tucker, Charles W. (1992).
Simulating individual and collective action In temporary
gatherings. Social Science Computer Review, 10(1), 1-28.
  Computer simulation of control systems in groups.

Petrie, Hugh G. (1981). The Dilemma of Inquiry and Learning.
Chicago: University of Chicago Press.

Powers, William T. (1973). Behavior: The Control of Perception.
Hawthorne, NY: Aldine DeGruyter.
  The basic text.

Powers, William T., The Nature of Robots:
  1 Defining Behavior BYTE 4(6), June 1979, p132-144, 7 pages.
  2 Simulated Control System, BYTE 4(7), July, 134-152, 12p.
  3 A Closer Look at Human Behavior, BYTE 4(8), Aug, 94-116, 16p.
  4 Looking for Controlled Variables, BYTE 4(8), Sep 96-112, 13p.

Powers, William T. (1989). Living Control Systems: Selected
Papers. NC: New View.
  Previously published papers, 1960-1988.

Powers, William T. (1992). Living Control Systems II: Selected
Papers. NC: New View.
  Previously unpublished papers, 1959-1990

Richardson, George P. (1991). Feedback Thought in Social Science
and Systems Theory. Philadelphia: University of Pennsylvania
Press.
  A review of systems thinking, including PCT.

Robertson, Richard J. and Powers, William T. (Eds.). (1990).
Introduction to Modern Psychology: The Control Theory View. NC:
New View.
  College-level text.

Runkel, Philip J. (1990). Casting Nets and Testing Specimens. New
York: Praeger.
  When statistics are appropriate; when models are required.

                         - END -

INTROCSG.NET

This file is posted every month to CSGnet.

       INTRODUCTION TO PERCEPTUAL CONTROL THEORY (PCT)
               THE CONTROL SYSTEMS GROUP (CSG)
        AND THE CONTROL SYSTEMS GROUP NETWORK (CSGnet)

          Prepared by Dag Forssell with Gary Cziko
                  Updated January 31, 1996

This is an introduction to Perceptual Control Theory (PCT), and the
discussion group CSGnet. CSGnet is listed on Usenet as the
newsgroup "bit.sci.purposive-behavior." This introduction is
posted at the beginning of each month for newcomers to CSGnet and
the newsgroup.

A complementary, more detailed "PCT Introduction and Resource
Guide" is available from the WWW server shown below (file
RESOURCE.PCT, 75 KB), or by mail (20 pages) as shown in the section
on references and order forms. It features the book jacket for
_Behavior: The Control of Perception_; two short essays by Bill
Powers: _An essay on the obvious_ and _Things I'd like to say if
they wouldn't think I am a nut_, which deal with the requirements
for and consequences of applying physical science to the field of
psychology; the foreword for _Living Control Systems II_ by Tom
Bourbon and more; plus more detailed descriptions of PCT books,
videos, order forms etc.

This introduction provides information about:

   Perceptual Control Theory (PCT): What it is
   Introductions to Perceptual Control Theory
   The Evolution of the Control Paradigm
   Demonstrating the Phenomenon of Control
   The Purpose of CSGnet
   CSGnet Participants
   Asking Questions
   Post Format
   The Control Systems Group
   Accessing and Subscribing to CSGnet
   Gopher and World-Wide Web
   On-line documents
   References
   Order Forms

   PERCEPTUAL CONTROL THEORY (PCT): WHAT IT IS

PCT offers a clear explanation for the pervasive phenomenon of
control, which is also known as purposeful behavior. Hierarchical
PCT (HPCT) outlines a hierarchical arrangement as a likely
organization of multiple control systems, which can explain the
purposeful behavior of living organisms.

PCT and HPCT were developed by William T. Powers, and introduced in
his 1973 book _Behavior: The Control of Perception_. (See
references and order forms, below). Powers shows us that the
engineering concept of control helps improve our understanding of
behavior, conflict, cooperation, and personal relationships. Just
as the in-depth explanatory theories of modern physical science
have helped us understand inanimate objects better than was
possible with experience and descriptive theories alone, the
in-depth explanations of PCT help us understand living organisms
better than has been possible with experience and descriptive
theories.

PCT focuses on how we look at and experience things, and the way
these perceptions are compared with experiences we want. The
difference produces action and physiology. Thus PCT explains how
thoughts become actions, feelings and results, and its principles
can be applied to any activity involving human experience.

PCT helps us understand people as they naturally are, just as
engineers understand physical phenomena as they naturally are. PCT
is remarkably simple, but like any other applied science, it
requires an understanding of basic principles and practice in their
application.

Much of the discussion on CSGnet reflects the rigorous "engineering
science" discipline of PCT and HPCT. Those who apply PCT and HPCT
to issues of personal relationships, education and management are
applying the basic principles to areas where they have not yet been
proven with scientific rigor, but seem to work well indeed.

  INTRODUCTIONS TO PERCEPTUAL CONTROL THEORY

Here are introductions by Bill and Mary Powers:

                 * * * * * * * *

  There have been two paradigms in the behavioral sciences since
  the 1600's. One was the idea that events impinging on organisms
  make them behave as they do. The other, which was developed in
  the 1930's, is PERCEPTUAL CONTROL THEORY (PCT). Perceptual
  Control Theory explains how organisms control what happens to
  them. This means all organisms from the amoeba to humankind. It
  explains why one organism can't control another without physical
  violence. It explains why people deprived of any major part of
  their ability to control soon become dysfunctional, lose interest
  in life, pine away and die. It explains what a goal is, how goals
  relate to action, how action affects perceptions and how
  perceptions define the reality in which we live and move and have
  our being. Perceptual Control Theory is the first scientific
  theory that can handle all these phenomena within a single,
  testable concept of how living systems work.

           William T. Powers, November 3, 1991

                 * * * * * * * *

  While the existence of control mechanisms and processes (such as
  feedback) in living systems is generally recognized, the
  implications of control organization go far beyond what is
  generally accepted. We believe that a fundamental characteristic
  of organisms is their ability to control; that they are, in fact,
  living control systems. To distinguish this approach from others
  using some version of control theory but forcing it to fit
  conventional approaches, we call ours Perceptual Control Theory,
  or PCT.

  PCT requires a major shift in thinking from the traditional
  approach: that what is controlled is not behavior, but
  perception. Modelling behavior as a dependent variable, as a
  response to stimuli, provides no explanation for the phenomenon
  of achieving consistent ends through varying means, and requires
  an extensive use of statistics to achieve modest (to the point of
  meaningless) correlations. Attempts to model behavior as planned
  and computed output can be demonstrated to require levels of
  precise calculation that are unobtainable in a physical system,
  and impossible in a real environment that is changing from one
  moment to the next. The PCT model views behavior as the means by
  which a perceived state of affairs is brought to and maintained
  at a reference state. This approach provides a physically
  plausible explanation for the consistency of outcomes and the
  variability of means.

  The PCT model has been used to simulate phenomena as diverse as
  bacterial chemotaxis, tracking a target, and behavior in crowds.
  In its elaborated form, a hierarchy of perceptual control systems
  (HPCT), it has lent itself to a computer simulation of tracking,
  including learning to track, and to new approaches to education,
  management, and psychotherapy.

  Control systems are not new in the life sciences. However,
  numerous misapprehensions exist, passed down from what was
  learned about control theory by non-engineers 40 or 50 years ago
  without further reference to newer developments or correction of
  initial misunderstandings. References in the literature to the
  desirability of positive feedback and the assertion that systems
  with feedback are slower than S-R systems are simply false, and
  concerns about stability are unfounded.

  The primary barrier to the adoption of PCT concepts is the
  belief--or hope--that control theory can simply be absorbed into
  the mainstream life sciences without disturbing the status quo.
  It is very hard to believe that one's training and life work, and
  that of one's mentors, and their mentors, must be fundamentally
  revised. Therefore, PCT appeals to those who feel some
  dissatisfaction with the status quo, or who are attracted to the
  idea of a generative model with broad application throughout the
  life sciences (plus AI and robotics). There are very few people
  working in PCT research. Much of its promise is still simply
  promise, and it meets resistance from all sides. It is
  frustrating but also tremendously exciting to be a part of the
  group who believe that they are participating in the birth of a
  true science of life.

           Mary Powers, November 1992

                 * * * * * * * *

  THE EVOLUTION OF THE CONTROL PARADIGM

The PCT paradigm originates in 1927, when an engineer named Harold
Black completed the technical analysis of closed loop control
systems. He was working with the negative feedback amplifier, which
is a control device. This led to a new engineering discipline and
the development of many purposeful machines. Purposeful machines
have built-in intent to achieve specified ends by variable means
under changing conditions.

The explanation for the phenomenon of control is the first
alternative to the linear cause-effect perspective ever proposed in
any science.

The first discussion of purposeful machines and people came in 1943
in a paper called: Behavior, Purpose and Teleology by Rosenblueth,
Wiener and Bigelow. This paper also argued that purpose belongs in
science as a real phenomenon in the present. Purpose does not mean
that somehow the future influences the present.

William T. (Bill) Powers developed PCT, beginning in the mid-50's.
In 1973 his book called "Behavior: the Control of Perception."
(often referred to as B:CP) was published. It is still the major
reference for PCT and discussion on CSGnet.

B:CP spells out a suggestion for a working model of how the human
brain and nervous system works. Our brain is a system that controls
its own perceptions. This view suggests explanations for many
previously mysterious aspects of how people interact with their
world.

Perceptual Control Theory has been accepted by independently
thinking psychologists, scientists, engineers and others. The
result is that an association has been formed (the Control System
Group), several books published, this CSGnet set up and that
several professors teach PCT in American universities today.

  DEMONSTRATING THE PHENOMENON OF CONTROL

Few scientists recognize or understand the phenomenon of control.
It is not well understood in important aspects even by many control
engineers. Yet the phenomenon of control, when it is recognized and
understood, provides a powerful enhancement to scientific
perspectives.

It is essential to recognize that control exists and deserves an
explanation before any of the discourse on CSGnet will make sense.

Please download the introductory computer demonstrations,
simulations and tutorials, beginning with "demo1". See "Gopher and
World-Wide Web" below for obtaining files via FTP, Gopher, and WWW.

  THE PURPOSE OF CSGnet

CSGnet provides a forum for development, use and testing of PCT.

  CSGnet PARTICIPANTS

Many interests and backgrounds are represented here. Psychology,
Sociology, Linguistics, Artificial Intelligence, Robotics, Social
Work, Neurology, Modeling and Testing. All are represented and
discussed. As of March 20, 1995 there were 146 individuals from 20
countries subscribed to CSGnet.

  ASKING QUESTIONS

Please introduce yourself with a statement of your professional
interests and background. It will help someone answer if you spell
out which demonstrations, introductory papers and references you
have taken the time to digest.

  POST FORMAT

When you are ready to introduce yourself and post to CSGnet, please
begin each post with your name and date of posting at the beginning
of the message itself, as shown here:

[From Dag Forssell (960212 1600)]

This lets readers know who sent the message, and when (sometimes
very different from the automated datestamp). It provides a
convenient reference for replies. When you respond to a message,
please use this reference (remove the word "From"), and quote only
relevant parts of the message you comment on.

  THE CONTROL SYSTEMS GROUP

The CSG is an organization of people in the behavioral, social, and
life sciences who see the potential in PCT for increased
understanding in their own fields and for the unification of
diverse and fragmented specialties.

Annual dues are $20 for full members and $5 for students.

The Twelfth North American Annual Meeting of the CSG will held in
1996 from July 17 to 21 at Northern Arizona University in
Flagstaff, Arizona. Shuttle service from the Phoenix airport to
Flagstaff will be available. There will be seven plenary meetings
(mornings and evenings), with afternoons, mealtimes, and late night
free for further discussion or recreation. Full details will be
available on CSGnet or by mail after April 1, 1996. The Second
Meeting of the European Control Systems Group (ECSG) will also be
held in 1996. Details to be arranged and posted on this net.

For membership information write:
CSG, c/o Mary Powers, 73 Ridge Place CR 510, Durango, CO 81301-8136
USA or send e-mail to powers_w@fortlewis.edu.

  ACCESSING AND SUBSCRIBING TO CSGnet

CSGnet can also be accessed via Usenet where it is listed as the
newsgroup "bit.sci.purposive-behavior" (NOTE: You may have to set
your default news server to news.cso.uiuc.edu to read this group.)

To subscribe to the listserv version of CSGnet, and learn about
options & commands, subscribers and archives, send a message to

LISTSERV@POSTOFFICE.CSO.UIUC.EDU

Message: (Comments: Not part of your message)

Subscribe CSGnet Firstname Lastname Institution (Your OWN name)
help (Basic introduction to commands)
info refcard (Comprehensive reference of commands)
set CSGnet digest * (Deliver one day's worth every morning)
set CSGnet repro (Get copy of your own postings)
set CSGnet ack (Receive acknowledgements when posting)
query CSGnet (Your mail status & options)
review CSGnet countries (Subscribers & addresses, by country)
index CSGnet (List of archive files available to you)
get CSGnet LOG9602B (Get archive for second week of Feb 1996,
                           shown here as an example only. Archives
                           can also be accessed via anonymous FTP
                           at postoffice.cso.uiuc.edu/csgnet).

* The alternatives are:
set CSGnet mail (Get messages as they are posted)
set CSGnet nomail (Stop the mail temporarily)

The Bitnet address for the list server is listserv@uiucvmd.

To remove yourself from the listserv version of CSGnet, send a
message as follows to LISTSERV@POSTOFFICE.CSO.UIUC.EDU

Unsub CSGnet

For the "unsub" command to work, the command must be sent with the
same return address used for the original "subscribe" command.

Messages to the entire CSGnet community should be addressed to
CSGnet@POSTOFFICE.CSO.UIUC.EDU

For more information about accessing CSGnet, contact Gary Cziko,
the network manager, at g-cziko@uiuc.edu

  GOPHER AND WORLD-WIDE WEB

A number of documents as well as MS-DOS and Mackintosh computer
programs can be obtained via Gopher and the World-Wide Web
(currently under construction).

To use a Gopher browser, connect to gopher.ed.uiuc.edu and follow
the path:

Higher Education Resources/
Professional societies & journals/
Control Systems Group

or from your favorite Gopher server follow the path:

Other Gopher and Information Servers/
North America/
USA/
illinois/
University of Ill.--College of Education/
Higher Education Resources/
Professional societies & journals/
Control Systems Group

The WWW address for the CSG homepage (under construction) is
http://www.ed.uiuc.edu/csg/ (don't forget the final slash).

  ON-LINE DOCUMENTS

A large collection of extracts from CSGnet discussions can be found
at on the World Wide Web at
http://www.ed.uiuc.edu/csg/documents/docindex.html. In addition,
extracts from selected published works can be found among the
references list below.

  REFERENCES

Here are some selected books, papers and computer programs on
Perceptual Control Theory. For a very complete list of CSG-related
publications, get the file biblio.pct from the fileserver as
described above. See also the "PCT Introduction and Resource Guide"
and order forms below.

                 * * * * * * * *

Bourbon, WT, KE Copeland, VR Dyer, WK Harman & BL Mosely (1990). On
the accuracy and reliability of predictions by control-system
theory. Perceptual and Motor Skills, vol 71, 1990, 1331-1338.
  The first of a 20-year series demonstrating the long-term
  reliability and stability of predictions generated by the PCT
  model.

Bourbon, W. Tom (In Press). Perceptual Control Theory. In: HL
Roitblat & J-A Meyer (eds.). Comparative approaches to cognitive
science. Cambridge, MA: MIT Press.
  Chapter surveys applications of PCT modeling by Bill Powers and
  Greg Williams (pointing, from the ARM/LITTLE MAN program); by
  Rick Marken and Bill Powers (movement "up a gradient" by E.
  coli), by Bill Powers, Clark Mcphail and Chuck Tucker (social
  movement and static formations, from the GATHERINGS program), and
  by Bourbon (tracking). The PCT model is contrasted with some of
  the mainstream models and theories presented at the workshop.

Cziko, Gary A. (1992). Purposeful behavior as the control of
perception: Implications for educational research. Educational
Researcher, 21(9), 10-18, 27.
  Introduction to PCT and implications for educational research.

Cziko, Gary A. (1992). Perceptual control theory: One threat to
educational research not (yet?) faced by Amundson, Serlin, and
Lehrer. Educational Researcher, 21(9), 25-27.
  Response to critics of previous article.

Cziko, Gary. (1995). Without miracles: Universal selection theory
and the second Darwinian evolution. Cambridge: MIT Press/A Bradford
Book.
     See Chapter 8, "Adapted Behavior as the Control of Perception"

Ford, Edward E. (1989). Freedom From Stress. Scottsdale AZ: Brandt
Publishing. A self-help book.
  PCT in a counseling framework.

Ford, Edward E. (1987). Love Guaranteed; A Better Marriage In 8
Weeks. Scottsdale AZ: Brandt Publishing.

Ford, Edward E. (1994). Discipline for Home and School. Scottsdale
AZ: Brandt Publishing.
  Teaches school personnel and parents how to deal effectively with
  children.

Forssell, Dag C., (1993). Perceptual Control: A New Management
Insight. In Engineering Management Journal, 5(4), 17-25.

Forssell, Dag C., (1994). Perceptual Control: Management Insight
for Problem Solving. In Engineering Management Journal, 6(3),
31-39.

Forssell, Dag C., (1995). Perceptual Control: Leading
Uncontrollable People. In Engineering Management Journal, 7(1), 38-
45.

Forssell, Dag C., (1994). Management and Leadership: Insight for
Effective Practice.
  A collection of articles (shown above) and working papers in book
  form introducing and applying PCT in the context of business and
  industry.

Forssell, Dag C. (Ed.), (1995). PCTdemos and PCTtexts. Two DOS
disks 1.44 MB 3 1/2". May be freely copied. Also available at the
WWW site shown above.
  PCTdemos holds eight different tutorial, simulation and
  demonstration programs with documentation. PCTtexts holds 3+ MB
  of essays, explanation, and debate.

Gibbons, Hugh. (1990). The Death of Jeffrey Stapleton: Exploring
the Way Lawyers Think. Concord, NH: Franklin Pierce Law Center.
  A text for law students using control theory.

Hershberger, Wayne. (Ed.). (1989). Volitional Action: Conation and
Control (Advances in Psychology No. 62). NY: North-Holland.
  16 of 25 articles on or about PCT.

Judd, Joel. (1992). Second Language Acquisition as the Control of
Nonprimary Linguistic Perception: A Critique of Research and
Theory. Unpublished doctoral dissertation, University of Illinois
at Champaign-Urbana. Dissertation Abstracts International, 53, (7),
#9236495.

Marken, Richard S. (Ed.). (1990). Purposeful Behavior: The control
theory approach. American Behavioral Scientist, 34(1). (Thousand
Oaks, CA: Sage Publications).
  11 articles on control theory.

Marken, Richard S. (1992). Mind Readings: Experimental Studies of
Purpose. NC: New View.
  Research papers exploring control.

McClelland, Kent. 1994. Perceptual Control and Social Power.
Sociological Perspectives 37(4):461-496.

McClelland, Kent. On Cooperatively Controlled Perceptions and
Social order. Available from the author, Dept. of Sociology,
Grinnell College, Grinnell IOWA 50112 USA.

McPhail, Clark. (1990). The Myth of the Madding Crowd. New York:
Aldine de Gruyter.
  Introduces control theory to explain group behavior.

McPhail, Clark., Powers, William T., & Tucker, Charles W. (1992).
Simulating individual and collective action In temporary
gatherings. Social Science Computer Review, 10(1), 1-28.
  Computer simulation of control systems in groups.

Petrie, Hugh G. (1981). The Dilemma of Inquiry and Learning.
Chicago: University of Chicago Press.

Powers, William T. (1973). Behavior: The Control of Perception.
Hawthorne, NY: Aldine DeGruyter.
  The basic text.

Powers, William T., The Nature of Robots:
  1 Defining Behavior BYTE 4(6), June 1979, p132-144, 7 pages.
  2 Simulated Control System, BYTE 4(7), July, 134-152, 12p.
  3 A Closer Look at Human Behavior, BYTE 4(8), Aug, 94-116, 16p.
  4 Looking for Controlled Variables, BYTE 4(8), Sep 96-112, 13p.

Powers, William T. (1989). Living Control Systems: Selected Papers.
NC: New View.
  Previously published papers, 1960-1988.

Powers, William T. (1992). Living Control Systems II: Selected
Papers. NC: New View.
  Previously unpublished papers, 1959-1990

Richardson, George P. (1991). Feedback Thought in Social Science
and Systems Theory. Philadelphia: University of Pennsylvania Press.
  A review of systems thinking, including PCT.

Robertson, Richard J. and Powers, William T. (Eds.). (1990).
Introduction to Modern Psychology: The Control Theory View. NC: New
View.
  College-level text.

Runkel, Philip J. (1990). Casting Nets and Testing Specimens. New
York: Praeger.
  When statistics are appropriate; when models are required.

                 * * * * * * * *

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INTROCSG.NET

This file is posted every month to CSGnet.

       INTRODUCTION TO PERCEPTUAL CONTROL THEORY (PCT)
               THE CONTROL SYSTEMS GROUP (CSG)
        AND THE CONTROL SYSTEMS GROUP NETWORK (CSGnet)

          Prepared by Dag Forssell with Gary Cziko
                  Updated January 1, 1997

This is an introduction to Perceptual Control Theory (PCT), and
the discussion group CSGnet. CSGnet is listed on Usenet as the
newsgroup "bit.sci.purposive-behavior." This introduction is
posted at the beginning of each month for newcomers to CSGnet and
the newsgroup.

A complementary "PCT Introduction and Resource Guide" is available
from the WWW server shown below (Resource.pct). It features the
original book jacket for Bill Powers' seminal 1973 book _Behavior:
The Control of Perception_; two short essays: _An essay on the
obvious_ and _Things I'd like to say if they wouldn't think I am a
nut_, which deal with the requirements for and consequences of
applying physical science to the field of psychology; the foreword
for _Living Control Systems II_ by Tom Bourbon and more; plus more
detailed descriptions of PCT books, videos, articles, sources,
etc.

Contents:

   Introductions to Perceptual Control Theory
   The Evolution of the Control Paradigm
   Demonstrating the Phenomenon of Control
   The Purpose of CSGnet
   CSGnet Participants
   Asking Questions
   Post Format
   The Control Systems Group
   Accessing and Subscribing to CSGnet
   World-Wide Web
   On-line documents
   References

  INTRODUCTIONS TO PERCEPTUAL CONTROL THEORY

  STANDING AT THE CROSSROADS

            Distributed at the Control Systems Group Meeting,
            August 15-19,1990, at Indiana, Pennsylvania.

  By William T. Powers.
           [Comments by Dag Forssell, Jan 1, 1997]

  I'd like to try today to give you the sense that psychology is
  standing at a crossroads -- and not only psychology, but all the
  sciences of life. We are about to experience the advent of
  something for which many people have searched, an organizing
  scheme that pulls together all the disparate schools of thought,
  specializations, movements, and evanescent fads that make up
  various fragmented branches of the life sciences.

  The organizing scheme is called "Perceptual* Control Theory."
  This theory explains a phenomenon, as theories are supposed to
  do. The phenomenon in question is called control. Everyone has
  heard this word, and most people have occasion to use it from
  time to time, but in science it has become part of the
  metalanguage rather than designating a subject of study. A
  scientist does a control experiment, or demonstrates how
  manipulation of stimuli and rewards can control an animal's
  movements, or advocates a proper diet to control cholesterol
  level or competes for control of a department. This word is used
  as part of a background of ordinary language, but it has not
  been part of the technical language of the life sciences.

     [* The word Perceptual was added at a later conference to
     distinguish Bill Power's creation from competing, non-
     functional interpretations by other authors. This term is
     technically more precise, since all control systems actually
     control their perceptions, not their outputs.]

  The reason is quite simple: nobody in or out of science
  understood the process of control until about the beginning of
  World War 2. By understanding the process, I mean being able to
  define it, characterize it, measure its parameters, predict how
  it will proceed, and recognize it in a real system. This doesn't
  mean that control was impossible to accomplish before World War
  2: after all, most people accomplish digestion without
  understanding any biochemistry. But control is as natural a
  process as digestion, and like digestion can be understood in a
  scientific way only by studying it and learning how it works.

  World War 2 started only about 50 years ago. Perhaps you can see
  why this fact implies some problems with studying control as a
  natural process. If control is a natural process, it was
  occurring in 1840, 1740, 1640, and so on back to the primordial
  ooze. In 1940, the sciences of life were already something like
  300 years old (and their prehistory was far older than that). If
  nobody understood control until 1940, it's clear that these
  sciences went through a major part of their development without
  taking it into account. The next question is obvious: how did
  they explain the phenomena that arise from processes of control?

  Many of the puzzles and controversies that occupied early
  researchers could have been resolved if scientists had realized
  that they were dealing with control processes. Purpose could
  have been studied scientifically instead of merely
  theologically. We can see now that all these early researchers,
  not recognizing a control process when they saw one, were
  drastically misled by some side-effects of control. The
  principal side-effect that deceived them resulted from the way
  control systems act in the presence of disturbances of the
  variables they control. When a disturbance occurs, a control
  system acts automatically to oppose the incipient change in the
  controlled variable. But if this opposition is not recognized
  (it's not always obvious), the observer will inevitably be led
  to see the cause of the disturbance as a stimulus and the action
  opposing its effects as a response to the stimulus. Furthermore,
  this opposition results in stabilizing some aspect of the
  environment or organism- environment relationship. That
  stabilization conceals the role of the stabilized variable in
  behavior; the better the control, the lower will be the
  correlation between the controlled variable and the actions that
  stabilize it. The variable under control is the one that is
  actually being sensed, but the logic of control makes it seem
  that the disturbance is the sensory stimulus.

  Donald T. Campbell [Late Professor of Psychology, Lehigh
  University] has proposed a "fish-scale" metaphor of scientific
  progress. Each worker constructs just one small scale that
  overlaps those already laid down by others. Eventually the whole
  fish will be covered completely. But what if the fish is a red
  herring? Then all these patient workers will devote their lives
  to covering the wrong fish. The converse of the fish-scale
  metaphor is that a person who is concentrating on fitting one
  little scale to others already laid down is bound to have a very
  localized view of the problem. Seeking to extend the
  accomplishments of others, a single worker can make what seems
  to be progress -- but it is unlikely that a single worker will
  discover that something is wrong with the whole design. The
  result can easily be the diligent application of fish-scales to
  a giraffe.

  I submit that something like this has happened in the life
  sciences. A fundamental misconception of the nature of behavior,
  natural but nevertheless horrendous, has pointed the life
  sciences down the wrong trail. Nearly all life scientists,
  particularly those who try to achieve objectivity and uniform
  methodology, have interpreted behavior as if it were caused by
  events outside an organism acting on a mechanism that merely
  responds. This hypothesis has become so ingrained that it is
  considered to be a basic philosophical principle of science. To
  explain behavior, one varies independent variables and records
  the ensuing actions; to analyze the data, one assumes a causal
  link from independent to dependent variable and calculates a
  correlation or computes a transfer function. This leads in turn
  to models of behaving systems in which inputs are transformed by
  hypothetical processes into motor outputs; those models lead to
  explorations of inner processes (as in neurology and
  biochemistry) predicated on the assumption that one is looking
  for links in an input-output chain. One assumption leads to the
  next until a whole structure has been built up, one that governs
  our thinking at every level of analysis from the genetic to the
  cognitive.

  Perceptual control theory, by showing us an alternative way of
  understanding this entire structure, therefore threatens the
  integrity of practically every bit of knowledge about behavior
  that has ever been set down on paper.

  This is, of course, a message of the type that leads to a high
  mortality among messengers. That is why you are listening to a
  person with no reputation to lose and no fame to protect,
  instead of a Nobel Prize winner. In an utterly predictable way,
  scientists have for the last 50 years gone to great lengths to
  avoid learning control theory or else to assimilate it into the
  existing picture of behavior. Failing that, they have simply
  declared it irrelevant to their own fields, with the result that
  the authoritative literature of perceptual control theory is
  almost completely insulated from the mainstream. It appears in
  publications like proceedings of the Institute of Electrical
  Engineers division on Man, Machines, and Cybernetics, or in
  human factors and manual control publications, or in Xeroxed
  papers passed from hand to hand. There is a scattered literature
  on perceptual control theory in the life sciences, but nothing
  on this subject gets past the referees into a standard journal
  without first having its teeth pulled.

  Despite all the defenses, the concepts of perceptual control
  theory are spreading. When our descendants look back on the
  latter half of the 20th Century, they will probably be amazed
  at the speed with which perceptual control theory became
  accepted: 50 years in the course of a science is nothing. We
  control theorists have nothing to complain about. Our greatest
  successes have come not through pounding at locked doors, but
  through continuing to explore the meaning of this new approach
  and learning how to apply it in many different disciplines. If
  we do our job correctly, acceptance will take care of itself.
  That job is not something one can toss off overnight, nor can it
  be done by just a handful of people. We are coming to a time of
  rigorous re-evaluation of all that is known or presumed to be
  known about the nature of organisms. The more people that are
  involved in this enormous project, the sooner it will be
  accomplished. That is why we are all so glad to welcome our
  guests at this session: after the party, you will be invited to
  help do the dishes.

  There has been progress in understanding how organisms work, the
  wrong model notwithstanding. Biochemical reactions are not going
  to change because of perceptual control theory. Muscles and
  nerves will continue to operate as they are known to operate.
  Even at more abstract levels of analysis, many phenomena will
  continue to be accepted as valid observations; for example,
  phenomena of perception, of memory, of cognition. If competently
  observed, these phenomena will still be part of the legacy of
  earlier workers. When we pull the stopper on the old theories,
  we must keep a strainer over the drain and let only the bath
  water out.

  Part of the task of reconstructing the sciences of life consists
  of separating valid observations of components from invalid
  conjectures about how they work together. Consider biochemistry
  as an example. Biochemistry is an odd mixture of solid research
  and wild leaps of undisciplined imagination. The research
  reveals chemical processes taking place in the microstructure of
  the body. The wild leaps propose that the chemical reactions
  somehow directly produce the behavioral effects with which they
  are associated. It's as though a specialist in solid-state
  physics were to propose that electrons flowing through wires and
  transistors are responsible for the music that comes out of a
  radio. While it's true that a shortage of electrons will make
  the music faint, and that without the electrons you wouldn't get
  any music, the physicist would be laughed out of town for
  suggesting that electrons cause music, or that you could fix a
  weak radio just by putting some more electrons into it. You
  can't understand the role of the electrons without grasping the
  principles of organization that make the radio different from a
  radio kit.

  In the same way, if shortages or excesses of chemicals like
  enzymes and neurotransmitters are found to be associated with
  functional and behavioral disorders, all we then know is that
  these substances play some role in the operation of the whole
  system that creates organized behavior. If there's a shortage of
  some chemical substance, then some other system has reduced its
  production of that substance, and some other system still has
  decreased its effect on the driving system, and so on in chains
  and causal loops. Nothing in a system as complex as the human
  body happens in isolation. If biochemistry is to have anything
  to say about the organism at any higher level, biochemists are
  going to have to study whole systems, not isolated reactions. We
  need a functional theory to supplement the microscopic laws of
  chemistry.

  There are workers in biochemistry who are investigating feedback
  control processes. One significant process involves an
  allosteric enzyme that is converted into an active form by the
  effect of one substance, and into an inactive form by the effect
  of another. When these two substances have the same
  concentration, the transition from active to inactive is
  balanced; the slightest imbalance of the substances causes a
  highly amplified offset toward the active or the inactive form.
  In one example, the active form catalyzes a main reaction, and
  the product of that reaction in turn enhances the substance that
  converts the enzyme to the inactive form -- a closed-loop
  relationship. The feedback is negative, because the active form
  of enzyme promotes effects that lead to a strong shift toward
  the inactive form. This little system very actively and
  accurately forces the concentration of the product of the main
  reaction to match the concentration of another substance, the
  one that biases the enzyme toward the active form. This allows
  one chemical system to control the effects that another one is
  having on the chemical environment.

  A person without some training in recognizing control processes
  might easily miss the fact that one chemical concentration is
  accurately controlling the product of a different reaction not
  directly related to the controlling substance. The effect of
  this control system is to create a relationship among
  concentrations that is imposed by organization, not simply by
  chemical laws. This is the kind of observation that a
  reductionist is likely to overlook; reductionism generally means
  failing to see the forest for the trees. Even the workers who
  described this control system mislabeled what it is doing --
  they concluded that this system controls the outflow of the
  product, when in fact it controls the concentration and makes it
  dependent on a different and chemically-unrelated substance.

  To shift through several gears, consider the lines of research
  that began with Rosenblatt's perceptron. This device was
  conceived as a behavioral system that could be trained to react
  to patterns contained in its input information. First this idea
  was shown, by something of a hatchet job, to be impractical, and
  then it was shown to be practical again if several levels of
  training could occur within it (I haven't seen any apologies to
  Frank Rosenblatt, who died without vindication). In all its
  incarnations, however, the perceptron has been thought of as a
  system that learns to "respond correctly" to a stimulus pattern.

  From the standpoint of perceptual control theory, however,
  organisms do not respond to stimuli but control input variables.
  So does that invalidate all that has been learned about
  perceptrons? Not at all. Perceptual control-theoretic models
  desperately need something like a perceptron to explain how
  abstract variables can be perceived. In a perceptual control
  model, however, the perceptron is only one component: it
  provides a signal that represents an aspect of some external
  state of affairs. It's easy to show that behavior can't be
  explained simply by converting such a signal into an output
  action. But behavior can be based on the difference between the
  perceptron's output signal and a reference signal that specifies
  the state of the perception that is to be brought about. The
  control-system model shows where the functions that are modeled
  as perceptrons belong in a model of the whole system.

  Shifting gears again: some theorists are trying to model motor
  behavior in terms of "motor programs" and "coordinative
  structures." In these models, command signals are presumed to be
  computed such that when applied to elastic muscles they produce
  the movements of a real limb. These models contain some
  impressive mathematics, taking into account the linkages of the
  limb and the dynamics of movement of the limb masses. But
  perceptual control theory says that behavior is not produced by
  computing output; it is produced by comparing inputs with
  desired inputs, and using the difference to drive output. No
  complicated "motor program" computer is needed. Does this mean
  that the mathematical analysis by the motor program people is
  spurious and ought to be discarded?

  Again, not at all. At some point in elaborating the perceptual
  control model, we must show how the driving signals actuate
  muscles to cause the movements we actually see. This entails
  solving all the physical equations for muscle and limb dynamics,
  just as the motor programmers have done. If they did their
  arithmetic right, it will still be right when we substitute the
  perceptual control-system model for the central-computer model.
  Both models have to produce the same driving signals. The only
  thing that will change is that perceptual control theory will
  show how the required driving signals arise naturally from
  perception and comparison against reference signals, instead of
  being computed blindly from scratch.

  Finally, shifting to overdrive, what do we do about Artificial
  Intelligence? We take advantage of whatever it really has to
  offer, modifying it only where we know it fails to explain
  enough. One place where it fails to explain enough is in the way
  it deals with action. Basically, it doesn't deal with action. It
  starts its analysis with perception of abstract variables in the
  form of symbols, constructs models that imitate human symbol-
  handling processes as well as possible, and finishes by
  generating more strings of symbols that describe actions to be
  taken. It says nothing useful about how a description of an
  action, in symbols, gets turned into just those muscle tensions
  that will in fact produce an action that fits the description.
  When devices are built that are run by symbol-processing
  computers, the critical transformations that make action out of
  symbols are simply put into the device by its builders. Many of
  those critical parts turn out to be servomechanisms --
  perceptual control systems.

  The assimilation of perceptual control theory into the life
  sciences will require a lot of this kind of reanalysis. Some old
  ideas will have to go, some will stay. This job is best done by
  people who are already competent in existing fields. Of course
  these also have to be people who can see that there is room for
  improvement along lines other than the standard ones.

  In the current membership of the Control Systems Group we have
  representatives of at least a dozen disciplines of the life
  sciences, and a few persons representing some unlikely
  occupations such as piano teaching and law. When these people
  meet, there is little difficulty in communicating because all of
  them have a basic understanding of perceptual control theory.
  But communication isn't the only factor that makes these
  meetings valuable. The most important lesson comes from seeing
  how perceptual control theory applies in someone else's field.

  The biggest problem with introducing perceptual control theory
  to scientists in conventional disciplines is that each scientist
  tends to think only of the scientific problems that are defined
  in that one field. The problem in question may involve behavior,
  but behavior is generally taken on faith to work the way some
  other specialist says it works. In fact most scientists tend to
  dismiss details involving other fields, assuming (often quite
  wrongly) that somebody else understands them well enough. We
  therefore find some very detailed biochemistry or neurology or
  personality- testing, all done competently, being used to
  explain behavioral phenomena that are very poorly analyzed and
  in many cases don't actually occur. The sociobiologist concludes
  that behavior patterns are inherited, not knowing that only the
  consequences of motor outputs, not the outputs themselves,
  repeat. What does a geneticist really know about the actions
  through which a bird catches a bug? You can inherit the
  perceptual control systems that are capable of catching bugs,
  but you can't inherit acts that happen to take you where a
  particular bug is going next. The combination of narrow
  expertise in one field and naive conceptions in every other
  field leads to facile explanations that are right only at one
  point.

  Specialists must see the need for a model of behavior that
  applies in all disciplines, even those in which the specialist
  is not competent. Once the Artificial Intelligence researcher
  understands exactly why organized behavior cannot be produced by
  computing outputs, he or she will modify the AI model so it will
  work correctly with more detailed systems actually capable of
  organized behavior. Important effects of learning how perceptual
  control theory applies in other fields will occur at the
  boundaries between disciplines -- exactly where we need to work
  if we are ever to have a unified science of life. At Control
  Systems Group meetings, specialists from many fields hear other
  specialists talking about the way perceptual control theory has
  made them rethink the problems in a different field. Because of
  the common understanding, this inevitably reveals one's own
  hasty assumptions, and encourages still more rethinking.

  One last remark about the CSG. The CSG does not represent any
  one scientific discipline. It has no agenda of its own beyond
  encouraging the application of perceptual control theory within
  existing disciplines -- no agenda, that is, except perhaps
  lowering the barriers between disciplines. The psychologists in
  the group are still psychologists, the sociologists are still
  sociologists, the therapists are still therapists, the engineers
  still engineers. This is not a political movement nor an
  alternative to established science. It is simply a vehicle for
  promoting interaction among people interested in using or
  learning more about perceptual control theory in any specialty
  whatsoever. When all the branches of the life sciences have
  assimilated and begun using perceptual control theory, the CSG,
  its work accomplished, will have no further reason to exist.

  In this presentation I have talked around perceptual control
  theory, alluding to some of its conclusions without attempting
  to justify or explain them. Learning perceptual control theory
  can't be done by listening to a half-hour's talk. I hope that
  some of you will find the promise of a unifying principle for
  the life sciences appealing enough to go further into this
  subject.

  * * * * * * * *

  Mary Powers, November 1992:

  While the existence of control mechanisms and processes (such as
  feedback) in living systems is generally recognized, the
  implications of control organization go far beyond what is
  generally accepted. We believe that a fundamental characteristic
  of organisms is their ability to control; that they are, in
  fact, living control systems. To distinguish this approach from
  others using some version of control theory but forcing it to
  fit conventional approaches, we call ours Perceptual Control
  Theory, or PCT.

  PCT requires a major shift in thinking from the traditional
  approach: that what is controlled is not behavior, but
  perception. Modelling behavior as a dependent variable, as a
  response to stimuli, provides no explanation for the phenomenon
  of achieving consistent ends through varying means, and requires
  an extensive use of statistics to achieve modest (to the point
  of meaningless) correlations. Attempts to model behavior as
  planned and computed output can be demonstrated to require
  levels of precise calculation that are unobtainable in a
  physical system, and impossible in a real environment that is
  changing from one moment to the next. The PCT model views
  behavior as the means by which a perceived state of affairs is
  brought to and maintained at a reference state. This approach
  provides a physically plausible explanation for the consistency
  of outcomes and the variability of means.

  The PCT model has been used to simulate phenomena as diverse as
  bacterial chemotaxis, tracking a target, and behavior in crowds.
  In its elaborated form, a hierarchy of perceptual control
  systems (HPCT), it has lent itself to a computer simulation of
  tracking, including learning to track, and to new approaches to
  education, management, and psychotherapy.

  Control systems are not new in the life sciences. However,
  numerous misapprehensions exist, passed down from what was
  learned about control theory by non-engineers 40 or 50 years ago
  without further reference to newer developments or correction of
  initial misunderstandings. References in the literature to the
  desirability of positive feedback and the assertion that systems
  with feedback are slower than S-R systems are simply false, and
  concerns about stability are unfounded.

  The primary barrier to the adoption of PCT concepts is the
  belief--or hope--that control theory can simply be absorbed into
  the mainstream life sciences without disturbing the status quo.
  It is very hard to believe that one's training and life work,
  and that of one's mentors, and their mentors, must be
  fundamentally revised. Therefore, PCT appeals to those who feel
  some dissatisfaction with the status quo, or who are attracted
  to the idea of a generative model with broad application
  throughout the life sciences (plus AI and robotics). There are
  very few people working in PCT research. Much of its promise is
  still simply promise, and it meets resistance from all sides. It
  is frustrating but also tremendously exciting to be a part of
  the group who believe that they are participating in the birth
  of a true science of life.

                 * * * * * * * *

  THE EVOLUTION OF THE CONTROL PARADIGM

The PCT paradigm originates in 1927, when an engineer named Harold
Black completed the technical analysis of closed loop control
systems. He was working with the negative feedback amplifier,
which is a control device. This led to a new engineering
discipline and the development of many purposeful machines.
Purposeful machines have built-in intent to achieve specified ends
by variable means under changing conditions.

The explanation for the phenomenon of control is the first
alternative to the linear cause-effect perspective ever proposed
in any science.

The first discussion of purposeful machines and people came in
1943 in a paper called: Behavior, Purpose and Teleology by
Rosenblueth, Wiener and Bigelow. This paper also argued that
purpose belongs in science as a real phenomenon in the present.
Purpose does not mean that somehow the future influences the
present.

William T. (Bill) Powers developed PCT, beginning in the mid-50's.
In 1973 his book called "Behavior: the Control of Perception."
(often referred to as B:CP) was published. It is still the major
reference for PCT and discussion on CSGnet.

B:CP spells out a suggestion for a working model of how the human
brain and nervous system works. Our brain is a system that
controls its own perceptions. This view suggests explanations for
many previously mysterious aspects of how people interact with
their world.

Perceptual Control Theory has been accepted by independently
thinking psychologists, scientists, engineers and others. The
result is that an association has been formed (the Control System
Group), several books published, this CSGnet set up and that
several professors teach PCT in American universities today.

  DEMONSTRATING THE PHENOMENON OF CONTROL

Few scientists recognize or understand the phenomenon of control.
It is not well understood in important aspects even by many
control engineers. Yet the phenomenon of control, when it is
recognized and understood, provides a powerful enhancement to
scientific perspectives.

It is essential to recognize that control exists and deserves an
explanation before any of the discourse on CSGnet will make sense.

Please download the introductory computer demonstrations,
simulations and tutorials, beginning with "demo1". See "World-Wide
Web" below for obtaining files via FTP and WWW.

  THE PURPOSE OF CSGnet

CSGnet provides a forum for development, use and testing of PCT.

  CSGnet PARTICIPANTS

Many interests and backgrounds are represented here. Psychology,
Sociology, Linguistics, Artificial Intelligence, Robotics, Social
Work, Neurology, Modeling and Testing. All are represented and
discussed. As of March 20, 1995 there were 146 individuals from 20
countries subscribed to CSGnet.

  ASKING QUESTIONS

Please introduce yourself with a statement of your professional
interests and background. It will help someone answer if you spell
out which demonstrations, introductory papers and references you
have taken the time to digest.

  POST FORMAT

When you are ready to introduce yourself and post to CSGnet,
please begin each post with your name and date of posting at the
beginning of the message itself, as shown here:

[From Dag Forssell (970212 1600)]

This lets readers know who sent the message, and when (sometimes
very different from the automated datestamp). It provides a
convenient reference for replies. When you respond to a message,
please use this reference (remove the word "From"), and quote only
relevant parts of the message you comment on.

  THE CONTROL SYSTEMS GROUP

The CSG is an organization of people in the behavioral, social,
and life sciences who see the potential in PCT for increased
understanding in their own fields and for the unification of
diverse and fragmented specialties.

Annual dues are $20 for full members and $5 for students.

The Thirteenth North American Annual Meeting of the CSG will held
in Durango, Colorado, from July 30 to August 3, 1997. There will
be seven plenary meetings (mornings and evenings), with
afternoons, mealtimes, and late night free for further discussion
or recreation. Full details will be available on CSGnet or by mail
after April 1, 1997.

For membership information write:
CSG, c/o Mary Powers, 73 Ridge Place CR 510, Durango, CO
81301-8136 USA or send e-mail to powers_w@FRONTIER.NET.

  ACCESSING AND SUBSCRIBING TO CSGnet

CSGnet can also be accessed via Usenet where it is listed as the
newsgroup "bit.sci.purposive-behavior" (NOTE: You may have to set
your default news server to news.cso.uiuc.edu to read this group.)

To subscribe to the listserv version of CSGnet, and learn about
options & commands, subscribers and archives, send a message to

LISTSERV@POSTOFFICE.CSO.UIUC.EDU

Message: (Comments: Not part of your message)

Subscribe CSGnet Firstname Lastname Institution (Your OWN name)
help (Basic introduction to commands)
info refcard (Comprehensive reference of commands)
set CSGnet digest * (Deliver one day's worth every morning)
set CSGnet repro (Get copy of your own postings)
set CSGnet ack (Receive acknowledgements when posting)
query CSGnet (Your mail status & options)
review CSGnet countries (Subscribers & addresses, by country)
index CSGnet (List of archive files available to you)
get CSGnet LOG9702B (Get archive for 2nd week of Feb 1997,
                          shown here as an example only. Archives
                          can also be accessed via anonymous FTP
                          at postoffice.cso.uiuc.edu/csgnet).

* The alternatives are:
set CSGnet mail (Get messages as they are posted)
set CSGnet nomail (Stop the mail temporarily)

The Bitnet address for the list server is listserv@uiucvmd.

To remove yourself from the listserv version of CSGnet, send a
message as follows to LISTSERV@POSTOFFICE.CSO.UIUC.EDU

Unsub CSGnet

For the "unsub" command to work, the command must be sent with the
same return address used for the original "subscribe" command.

Messages to the entire CSGnet community should be addressed to
CSGnet@POSTOFFICE.CSO.UIUC.EDU

For more information about accessing CSGnet, contact Gary Cziko,
the network manager, at g-cziko@uiuc.edu

  WORLD-WIDE WEB

A number of documents (including a hypertext version of this one)
and MS-DOS and MacIntosh computer programs can be obtained via FTP
(ftp://lynx.ed.uiuc.edu/LRS2/CSG/Computer_Programs/) and the
World-Wide Web (http://www.ed.uiuc.edu/csg/).

  ON-LINE DOCUMENTS

A large collection of extracts from CSGnet discussions can be
found at on the World Wide Web at
http://www.ed.uiuc.edu/csg/documents/docindex.html. In addition,
extracts from selected published works can be found among the
references listed below.

  REFERENCES

Here are some selected books, papers and computer programs on
Perceptual Control Theory. For a very complete list of CSG-related
publications, get the file biblio.pct from the fileserver as
described above. See also the "PCT Introduction and Resource
Guide."

                 * * * * * * * *

Bourbon, WT, KE Copeland, VR Dyer, WK Harman & BL Mosely (1990).
On the accuracy and reliability of predictions by control-system
theory. Perceptual and Motor Skills, vol 71, 1990, 1331-1338.
  The first of a 20-year series demonstrating the long-term
  reliability and stability of predictions generated by the PCT
  model.

Bourbon, W. Tom (In Press). Perceptual Control Theory. In: HL
Roitblat & J-A Meyer (eds.). Comparative approaches to cognitive
science. Cambridge, MA: MIT Press.
  Chapter surveys applications of PCT modeling by Bill Powers and
  Greg Williams (pointing, from the ARM/LITTLE MAN program); by
  Rick Marken and Bill Powers (movement "up a gradient" by E.
  coli), by Bill Powers, Clark Mcphail and Chuck Tucker (social
  movement and static formations, from the GATHERINGS program),
  and by Bourbon (tracking). The PCT model is contrasted with some
  of the mainstream models and theories presented at the workshop.

Cziko, Gary A. (1992). Purposeful behavior as the control of
perception: Implications for educational research. Educational
Researcher, 21(9), 10-18, 27.
  Introduction to PCT and implications for educational research.

Cziko, Gary A. (1992). Perceptual control theory: One threat to
educational research not (yet?) faced by Amundson, Serlin, and
Lehrer. Educational Researcher, 21(9), 25-27.
  Response to critics of previous article.

Cziko, Gary. (1995). Without miracles: Universal selection theory
and the second Darwinian evolution. Cambridge: MIT Press/A
Bradford Book.
     See Chap 8, "Adapted Behavior as the Control of Perception"

Ford, Edward E. (1989). Freedom From Stress. Scottsdale AZ: Brandt
Publishing. A self-help book.
  PCT in a counseling framework.

Ford, Edward E. (1987). Love Guaranteed; A Better Marriage In 8
Weeks. Scottsdale AZ: Brandt Publishing.

Ford, Edward E. (1994). Discipline for Home and School. Scottsdale
AZ: Brandt Publishing.
  Teaches school personnel and parents how to deal effectively
  with children.

Ford, Edward E. (1996). Discipline for Home and School, Book Two;
Program Standards for Schools. Scottsdale AZ: Brandt Publishing.
  Additional information focusing on the requirements for
  successful implementation.

Forssell, Dag C., (1994). Management and Leadership: Insight for
Effective Practice.
  A collection of articles and working papers in book form
  introducing and applying PCT in the context of business and
  industry.

Forssell, Dag C. (Ed.), (1995). PCTdemos and PCTtexts. Two DOS
disks 1.44 MB 3 1/2". May be freely copied. Also available at the
WWW site shown above.
  PCTdemos holds eight different tutorial, simulation and
  demonstration programs with documentation. PCTtexts holds 3+ MB
  of essays, explanation, and debate.

Gibbons, Hugh. (1990). The Death of Jeffrey Stapleton: Exploring
the Way Lawyers Think. Concord, NH: Franklin Pierce Law Center.
  A text for law students using control theory.

Hershberger, Wayne. (Ed.). (1989). Volitional Action: Conation and
Control (Advances in Psychology No. 62). NY: North-Holland.
  16 of 25 articles on or about PCT.

Judd, Joel. (1992). Second Language Acquisition as the Control of
Nonprimary Linguistic Perception: A Critique of Research and
Theory. Unpublished doctoral dissertation, University of Illinois
at Champaign-Urbana. Dissertation Abstracts International, 53,
(7), #9236495.

Marken, Richard S. (Ed.). (1990). Purposeful Behavior: The control
theory approach. American Behavioral Scientist, 34(1). (Thousand
Oaks, CA: Sage Publications).
  11 articles on control theory.

Marken, Richard S. (1992). Mind Readings: Experimental Studies of
Purpose. NC: New View.
  Research papers exploring control.

McClelland, Kent. 1994. Perceptual Control and Social Power.
Sociological Perspectives 37(4):461-496.

McClelland, Kent. On Cooperatively Controlled Perceptions and
Social order. Available from the author, Dept. of Sociology,
Grinnell College, Grinnell IOWA 50112 USA.

McPhail, Clark. (1990). The Myth of the Madding Crowd. New York:
Aldine de Gruyter.
  Introduces control theory to explain group behavior.

McPhail, Clark., Powers, William T., & Tucker, Charles W. (1992).
Simulating individual and collective action In temporary
gatherings. Social Science Computer Review, 10(1), 1-28.
  Computer simulation of control systems in groups.

Petrie, Hugh G. (1981). The Dilemma of Inquiry and Learning.
Chicago: University of Chicago Press.

Powers, William T. (1973). Behavior: The Control of Perception.
Hawthorne, NY: Aldine DeGruyter.
  The basic text.

Powers, William T., The Nature of Robots:
  1 Defining Behavior BYTE 4(6), June 1979, p132-144, 7 pages.
  2 Simulated Control System, BYTE 4(7), July, 134-152, 12p.
  3 A Closer Look at Human Behavior, BYTE 4(8), Aug, 94-116, 16p.
  4 Looking for Controlled Variables, BYTE 4(8), Sep 96-112, 13p.

Powers, William T. (1989). Living Control Systems: Selected
Papers. NC: New View.
  Previously published papers, 1960-1988.

Powers, William T. (1992). Living Control Systems II: Selected
Papers. NC: New View.
  Previously unpublished papers, 1959-1990

Richardson, George P. (1991). Feedback Thought in Social Science
and Systems Theory. Philadelphia: University of Pennsylvania
Press.
  A review of systems thinking, including PCT.

Robertson, Richard J. and Powers, William T. (Eds.). (1990).
Introduction to Modern Psychology: The Control Theory View. NC:
New View.
  College-level text.

Runkel, Philip J. (1990). Casting Nets and Testing Specimens. New
York: Praeger.
  When statistics are appropriate; when models are required.

                         - END -

[From Dag Forssell (950930 1201)]

INTROCSG.NET

This file is posted every month to CSG-L.

       INTRODUCTION TO PERCEPTUAL CONTROL THEORY (PCT)
               THE CONTROL SYSTEMS GROUP (CSG)
    AND THE CONTROL SYSTEMS GROUP NETWORK (CSG-L or CSGnet)

          Prepared by Dag Forssell with Gary Cziko
                  Updated September 30, 1995

This is an introduction to Perceptual Control Theory (PCT), and the
discussion group CSG-L. CSG-L is listed on Usenet as the newsgroup
"bit.sci.purposive-behavior." This introduction is posted at the
beginning of each month for newcomers to CSG-L and the newsgroup.

A complementary, more detailed "PCT Introduction and Resource
Guide" is available from the WWW server shown below (file
RESOURCE.PCT, 75 KB), or by mail (20 pages) as shown in the section
on references and order forms. It features the book jacket for
_Behavior: The Control of Perception_; two short essays by Bill
Powers: _An essay on the obvious_ and _Things I'd like to say if
they wouldn't think I am a nut_, which deal with the requirements
of developing psychology as physical science; the foreword for
_Living Control Systems II_ by Tom Bourbon and more; plus more
detailed descriptions of PCT books, videos, order forms etc.

This introduction provides information about:

   Perceptual Control Theory (PCT): What it is
   Introductions to Perceptual Control Theory
   The Evolution of the Control Paradigm
   Demonstrating the Phenomenon of Control
   The Purpose of CSGnet
   CSGnet Participants
   Asking Questions
   Post Format
   The Control Systems Group
   Accessing and Subscribing to CSGnet
   Gopher and World-Wide Web
   On-line documents
   References
   Order Forms

   PERCEPTUAL CONTROL THEORY (PCT): WHAT IT IS

PCT offers a clear explanation for the pervasive phenomenon of
control, which is also known as purposeful behavior. Hierarchical
PCT (HPCT) outlines a hierarchical arrangement as a likely
organization of multiple control systems, which can explain the
purposeful behavior of living organisms.

PCT and HPCT were developed by William T. Powers, and introduced in
his 1973 book _Behavior: The Control of Perception_. (See
references and order forms, below). Powers shows us that the
engineering concept of control helps improve our understanding of
behavior, conflict, cooperation, and personal relationships. Just
as the in-depth explanatory theories of modern physical science
have helped us understand inanimate objects better than was
possible with experience and descriptive theories alone, the
in-depth explanations of PCT help us understand living organisms
better than has been possible with experience and descriptive
theories.

PCT focuses on how we look at and experience things, and the way
these perceptions are compared with experiences we want. The
difference produces action and physiology. Thus PCT explains how
thoughts become actions, feelings and results, and its principles
can be applied to any activity involving human experience.

PCT helps us understand people as they naturally are, just as
engineers understand physical phenomena as they naturally are. PCT
is remarkably simple, but like any other applied science, it
requires an understanding of basic principles and practice in their
application.

Much of the discussion on CSG-L reflects the rigorous "engineering
science" discipline of PCT and HPCT. Those who apply PCT and HPCT
to issues of personal relationships, education and management are
applying the basic principles to areas where they have not yet been
proven with scientific rigor, but seem to work well indeed.

  INTRODUCTIONS TO PERCEPTUAL CONTROL THEORY

Here are introductions by Bill and Mary Powers:

                 * * * * * * * *

  There have been two paradigms in the behavioral sciences since
  the 1600's. One was the idea that events impinging on organisms
  make them behave as they do. The other, which was developed in
  the 1930's, is PERCEPTUAL CONTROL THEORY (PCT). Perceptual
  Control Theory explains how organisms control what happens to
  them. This means all organisms from the amoeba to humankind. It
  explains why one organism can't control another without physical
  violence. It explains why people deprived of any major part of
  their ability to control soon become dysfunctional, lose interest
  in life, pine away and die. It explains what a goal is, how goals
  relate to action, how action affects perceptions and how
  perceptions define the reality in which we live and move and have
  our being. Perceptual Control Theory is the first scientific
  theory that can handle all these phenomena within a single,
  testable concept of how living systems work.

           William T. Powers, November 3, 1991

                 * * * * * * * *

  While the existence of control mechanisms and processes (such as
  feedback) in living systems is generally recognized, the
  implications of control organization go far beyond what is
  generally accepted. We believe that a fundamental characteristic
  of organisms is their ability to control; that they are, in fact,
  living control systems. To distinguish this approach from others
  using some version of control theory but forcing it to fit
  conventional approaches, we call ours Perceptual Control Theory,
  or PCT.

  PCT requires a major shift in thinking from the traditional
  approach: that what is controlled is not behavior, but
  perception. Modelling behavior as a dependent variable, as a
  response to stimuli, provides no explanation for the phenomenon
  of achieving consistent ends through varying means, and requires
  an extensive use of statistics to achieve modest (to the point of
  meaningless) correlations. Attempts to model behavior as planned
  and computed output can be demonstrated to require levels of
  precise calculation that are unobtainable in a physical system,
  and impossible in a real environment that is changing from one
  moment to the next. The PCT model views behavior as the means by
  which a perceived state of affairs is brought to and maintained
  at a reference state. This approach provides a physically
  plausible explanation for the consistency of outcomes and the
  variability of means.

  The PCT model has been used to simulate phenomena as diverse as
  bacterial chemotaxis, tracking a target, and behavior in crowds.
  In its elaborated form, a hierarchy of perceptual control systems
  (HPCT), it has lent itself to a computer simulation of tracking,
  including learning to track, and to new approaches to education,
  management, and psychotherapy.

  Control systems are not new in the life sciences. However,
  numerous misapprehensions exist, passed down from what was
  learned about control theory by non-engineers 40 or 50 years ago
  without further reference to newer developments or correction of
  initial misunderstandings. References in the literature to the
  desirability of positive feedback and the assertion that systems
  with feedback are slower than S-R systems are simply false, and
  concerns about stability are unfounded.

  The primary barrier to the adoption of PCT concepts is the
  belief--or hope--that control theory can simply be absorbed into
  the mainstream life sciences without disturbing the status quo.
  It is very hard to believe that one's training and life work, and
  that of one's mentors, and their mentors, must be fundamentally
  revised. Therefore, PCT appeals to those who feel some
  dissatisfaction with the status quo, or who are attracted to the
  idea of a generative model with broad application throughout the
  life sciences (plus AI and robotics). There are very few people
  working in PCT research. Much of its promise is still simply
  promise, and it meets resistance from all sides. It is
  frustrating but also tremendously exciting to be a part of the
  group who believe that they are participating in the birth of a
  true science of life.

           Mary Powers, November 1992

                 * * * * * * * *

  THE EVOLUTION OF THE CONTROL PARADIGM

The PCT paradigm originates in 1927, when an engineer named Harold
Black completed the technical analysis of closed loop control
systems. He was working with the negative feedback amplifier, which
is a control device. This led to a new engineering discipline and
the development of many purposeful machines. Purposeful machines
have built-in intent to achieve specified ends by variable means
under changing conditions.

The explanation for the phenomenon of control is the first
alternative to the linear cause-effect perspective ever proposed in
any science.

The first discussion of purposeful machines and people came in 1943
in a paper called: Behavior, Purpose and Teleology by Rosenblueth,
Wiener and Bigelow. This paper also argued that purpose belongs in
science as a real phenomenon in the present. Purpose does not mean
that somehow the future influences the present.

William T. (Bill) Powers developed PCT, beginning in the mid-50's.
In 1973 his book called "Behavior: the Control of Perception."
(often referred to as B:CP) was published. It is still the major
reference for PCT and discussion on CSG-L.

B:CP spells out a suggestion for a working model of how the human
brain and nervous system works. Our brain is a system that controls
its own perceptions. This view suggests explanations for many
previously mysterious aspects of how people interact with their
world.

Perceptual Control Theory has been accepted by independently
thinking psychologists, scientists, engineers and others. The
result is that an association has been formed (the Control System
Group), several books published, this CSGnet set up and that
several professors teach PCT in American universities today.

  DEMONSTRATING THE PHENOMENON OF CONTROL

Few scientists recognize or understand the phenomenon of control.
It is not well understood in important aspects even by many control
engineers. Yet the phenomenon of control, when it is recognized and
understood, provides a powerful enhancement to scientific
perspectives.

It is essential to recognize that control exists and deserves an
explanation before any of the discourse on CSGnet will make sense.

Please download the introductory computer demonstrations,
simulations and tutorials, beginning with "demo1". See "Gopher and
World-Wide Web" below for obtaining files via FTP, Gopher, and WWW.

  THE PURPOSE OF CSGnet

CSGnet provides a forum for development, use and testing of PCT.

  CSGnet PARTICIPANTS

Many interests and backgrounds are represented here. Psychology,
Sociology, Linguistics, Artificial Intelligence, Robotics, Social
Work, Neurology, Modeling and Testing. All are represented and
discussed. As of March 20, 1995 there were 146 individuals from 20
countries subscribed to CSGnet.

  ASKING QUESTIONS

Please introduce yourself with a statement of your professional
interests and background. It will help someone answer if you spell
out which demonstrations, introductory papers and references you
have taken the time to digest.

  POST FORMAT

When you are ready to introduce yourself and post to CSG-L, please
begin each post with your name and date of posting at the beginning
of the message itself, as shown here:

[Dag Forssell (950212 1600)]

This lets readers know who sent the message, and when (sometimes
very different from the automated datestamp). It provides a
convenient reference for replies. When you respond to a message,
please use this reference and quote only relevant parts of the
message you comment on.

  THE CONTROL SYSTEMS GROUP

The CSG is an organization of people in the behavioral, social, and
life sciences who see the potential in PCT for increased
understanding in their own fields and for the unification of
diverse and fragmented specialties.

Annual dues are $20 for full members and $5 for students.

The Twelfth North American Annual Meeting of the CSG will held in
1996 from July 17 to 21 at Northern Arizona University in
Flagstaff, Arizona. Shuttle service from the Phoenix airport to
Flagstaff will be available. There will be seven plenary meetings
(mornings and evenings), with afternoons, mealtimes, and late night
free for further discussion or recreation. Full details will be
available on CSGnet or by mail after April 1, 1996. The Second
Meeting of the European Control Systems Group (ECSG) will also be
held in 1996. Details to be arranged and posted on this net.

For membership information write:
CSG, c/o Mary Powers, 73 Ridge Place CR 510, Durango, CO 81301-8136
USA or send e-mail to powers_w@fortlewis.edu.

  ACCESSING AND SUBSCRIBING TO CSGnet

CSGnet can also be accessed via Usenet where it is listed as the
newsgroup "bit.sci.purposive-behavior" (NOTE: You may have to set
your default news server to news.cso.uiuc.edu to read this group.)

To subscribe to the listserv version of CSGnet, and learn about
options & commands, subscribers and archives, send a message to

listserv@vmd.cso.uiuc.edu

Message: (Comments: Not part of your message)

Subscribe CSG-L Firstname Lastname Institution (Your OWN name)
help (Basic introduction to commands)
info refcard (Comprehensive reference of commands)
set CSG-L digest * (Deliver one day's worth every morning)
set CSG-L repro (Get copy of your own postings)
set CSG-L ack (Receive acknowledgements when posting)
query CSG-L (Your mail status & options)
review CSG-L countries (Subscribers & addresses, by country)
index CSG-L (List of archive files available to you)
get CSG-L LOG9502B (Get archive for second week of Feb 1995
                           --shown here as an example only).

* The alternatives are:
set CSG-L mail (Get messages as they are posted)
set CSG-L nomail (Stop the mail temporarily)

The Bitnet address for the list server is listserv@uiucvmd.

To remove yourself from the listserv version of CSGnet, send a
message as follows to listserv@vmd.cso.uiuc.edu

Unsub CSG-L

For the "unsub" command to work, the command must be sent with the
same return address used for the original "subscribe" command.

Messages to the entire CSGnet community should be addressed to
CSG-L@vmd.cso.uiuc.edu

For more information about accessing CSGnet, contact Gary Cziko,
the network manager, at g-cziko@uiuc.edu

  GOPHER AND WORLD-WIDE WEB

A number of documents as well as MS-DOS and Mackintosh computer
programs can be obtained via Gopher and the World-Wide Web
(currently under construction).

To use a Gopher browser, connect to gopher.ed.uiuc.edu and follow
the path:

Higher Education Resources/
Professional societies & journals/
Control Systems Group

or from your favorite Gopher server follow the path:

Other Gopher and Information Servers/
North America/
USA/
illinois/
University of Ill.--College of Education/
Higher Education Resources/
Professional societies & journals/
Control Systems Group

The WWW address for the CSG homepage (under construction) is
http://www.ed.uiuc.edu/csg/ (don't forget the final slash).

  ON-LINE DOCUMENTS

A large collection of extracts from CSGnet discussions can be found
at on the World Wide Web at
http://www.ed.uiuc.edu/csg/documents/docindex.html. In addition,
extracts from selected published works can be found among the
references list below.

  REFERENCES

Here are some selected books, papers and computer programs on
Perceptual Control Theory. For a very complete list of CSG-related
publications, get the file biblio.pct from the fileserver as
described above. See also the "PCT Introduction and Resource Guide"
and order forms below.

                 * * * * * * * *

Bourbon, WT, KE Copeland, VR Dyer, WK Harman & BL Mosely (1990). On
the accuracy and reliability of predictions by control-system
theory. Perceptual and Motor Skills, vol 71, 1990, 1331-1338.
  The first of a 20-year series demonstrating the long-term
  reliability and stability of predictions generated by the PCT
  model.

Bourbon, W. Tom (In Press). Perceptual Control Theory. In: HL
Roitblat & J-A Meyer (eds.). Comparative approaches to cognitive
science. Cambridge, MA: MIT Press.
  Chapter surveys applications of PCT modeling by Bill Powers and
  Greg Williams (pointing, from the ARM/LITTLE MAN program); by
  Rick Marken and Bill Powers (movement "up a gradient" by E.
  coli), by Bill Powers, Clark Mcphail and Chuck Tucker (social
  movement and static formations, from the GATHERINGS program), and
  by Bourbon (tracking). The PCT model is contrasted with some of
  the mainstream models and theories presented at the workshop.

Cziko, Gary A. (1992). Purposeful behavior as the control of
perception: Implications for educational research. Educational
Researcher, 21(9), 10-18, 27.
  Introduction to PCT and implications for educational research.

Cziko, Gary A. (1992). Perceptual control theory: One threat to
educational research not (yet?) faced by Amundson, Serlin, and
Lehrer. Educational Researcher, 21(9), 25-27.
  Response to critics of previous article.

Cziko, Gary. (1995). Without miracles: Universal selection theory
and the second Darwinian evolution. Cambridge: MIT Press/A Bradford
Book.
     See Chapter 8, "Adapted Behavior as the Control of Perception"

Ford, Edward E. (1989). Freedom From Stress. Scottsdale AZ: Brandt
Publishing. A self-help book.
  PCT in a counseling framework.

Ford, Edward E. (1987). Love Guaranteed; A Better Marriage In 8
Weeks. Scottsdale AZ: Brandt Publishing.

Ford, Edward E. (1994). Discipline for Home and School. Scottsdale
AZ: Brandt Publishing.
  Teaches school personnel and parents how to deal effectively with
  children.

Forssell, Dag C., (1993). Perceptual Control: A New Management
Insight. In Engineering Management Journal, 5(4), 17-25.

Forssell, Dag C., (1994). Perceptual Control: Management Insight
for Problem Solving. In Engineering Management Journal, 6(3),
31-39.

Forssell, Dag C., (1995). Perceptual Control: Leading
Uncontrollable People. In Engineering Management Journal, 7(1), 38-
45.

Forssell, Dag C., (1994). Management and Leadership: Insight for
Effective Practice.
  A collection of articles (shown above) and working papers in book
  form introducing and applying PCT in the context of business and
  industry.

Forssell, Dag C. (Ed.), (1995). PCTdemos and PCTtexts. Two DOS
disks 1.44 MB 3 1/2". May be freely copied. Also available at the
WWW site shown above.
  PCTdemos holds eight different tutorial, simulation and
  demonstration programs with documentation. PCTtexts holds 3+ MB
  of essays, explanation, and debate.

Gibbons, Hugh. (1990). The Death of Jeffrey Stapleton: Exploring
the Way Lawyers Think. Concord, NH: Franklin Pierce Law Center.
  A text for law students using control theory.

Hershberger, Wayne. (Ed.). (1989). Volitional Action: Conation and
Control (Advances in Psychology No. 62). NY: North-Holland.
  16 of 25 articles on or about PCT.

Judd, Joel. (1992). Second Language Acquisition as the Control of
Nonprimary Linguistic Perception: A Critique of Research and
Theory. Unpublished doctoral dissertation, University of Illinois
at Champaign-Urbana. Dissertation Abstracts International, 53, (7),
#9236495.

Marken, Richard S. (Ed.). (1990). Purposeful Behavior: The control
theory approach. American Behavioral Scientist, 34(1). (Thousand
Oaks, CA: Sage Publications).
  11 articles on control theory.

Marken, Richard S. (1992). Mind Readings: Experimental Studies of
Purpose. NC: New View.
  Research papers exploring control.

McClelland, Kent. 1994. Perceptual Control and Social Power.
Sociological Perspectives 37(4):461-496.

McClelland, Kent. On Cooperatively Controlled Perceptions and
Social order. Available from the author, Dept. of Sociology,
Grinnell College, Grinnell IOWA 50112 USA.

McPhail, Clark. (1990). The Myth of the Madding Crowd. New York:
Aldine de Gruyter.
  Introduces control theory to explain group behavior.

McPhail, Clark., Powers, William T., & Tucker, Charles W. (1992).
Simulating individual and collective action In temporary
gatherings. Social Science Computer Review, 10(1), 1-28.
  Computer simulation of control systems in groups.

Petrie, Hugh G. (1981). The Dilemma of Inquiry and Learning.
Chicago: University of Chicago Press.

Powers, William T. (1973). Behavior: The Control of Perception.
Hawthorne, NY: Aldine DeGruyter.
  The basic text.

Powers, William T., The Nature of Robots:
  1 Defining Behavior BYTE 4(6), June 1979, p132-144, 7 pages.
  2 Simulated Control System, BYTE 4(7), July, 134-152, 12p.
  3 A Closer Look at Human Behavior, BYTE 4(8), Aug, 94-116, 16p.
  4 Looking for Controlled Variables, BYTE 4(8), Sep 96-112, 13p.

Powers, William T. (1989). Living Control Systems: Selected Papers.
NC: New View.
  Previously published papers, 1960-1988.

Powers, William T. (1992). Living Control Systems II: Selected
Papers. NC: New View.
  Previously unpublished papers, 1959-1990

Richardson, George P. (1991). Feedback Thought in Social Science
and Systems Theory. Philadelphia: University of Pennsylvania Press.
  A review of systems thinking, including PCT.

Robertson, Richard J. and Powers, William T. (Eds.). (1990).
Introduction to Modern Psychology: The Control Theory View. NC: New
View.
  College-level text.

Runkel, Philip J. (1990). Casting Nets and Testing Specimens. New
York: Praeger.
  When statistics are appropriate; when models are required.

                 * * * * * * * *

  ORDER FORMS

  A free 20 page PCT Resource Guide with introductions and more
  detail on the references listed above and a few more --
  publishers, books, articles, videos, seminars, and the DOS
  demonstration disk -- may be obtained by sending a note with

  1) a self addressed, stamped (55 cents) envelope, or

  2) two "international reply" coupons
     - every post office in the world sells them.

           Dag Forssell
           23903 Via Flamenco
           Valencia, California, 91355-2808 USA.

The PCT Introduction and Resource Guide is also available in ASCII
format from the WWW site shown above.

Order forms in the Guide are reproduced below without descriptions.
All prices current as of April, 1995.

···

to: PCT Introduction and Resource Guide
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23903 Via Flamenco, Valencia, CA 91355-2808 USA Fax:(805) 254-7956

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  American Behavioral Scientist, Volume 34, Number 1 Sept/Oct 1990
       Stock number 201238 Richard S. Marken, Editor
       Purposeful Behavior; The Control Theory Approach,
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                            - END -

INTROCSG.NET

This file is posted every month to CSG-L.

       INTRODUCTION TO PERCEPTUAL CONTROL THEORY (PCT)
               THE CONTROL SYSTEMS GROUP (CSG)
    AND THE CONTROL SYSTEMS GROUP NETWORK (CSG-L or CSGnet)

          Prepared by Dag Forssell with Gary Cziko
                  Updated September 30, 1995

This is an introduction to Perceptual Control Theory (PCT), and the
discussion group CSG-L. CSG-L is listed on Usenet as the newsgroup
"bit.sci.purposive-behavior." This introduction is posted at the
beginning of each month for newcomers to CSG-L and the newsgroup.

A complementary, more detailed "PCT Introduction and Resource
Guide" is available from the WWW server shown below (file
RESOURCE.PCT, 75 KB), or by mail (20 pages) as shown in the section
on references and order forms. It features the book jacket for
_Behavior: The Control of Perception_; two short essays by Bill
Powers: _An essay on the obvious_ and _Things I'd like to say if
they wouldn't think I am a nut_, which deal with the requirements
of developing psychology as physical science; the foreword for
_Living Control Systems II_ by Tom Bourbon and more; plus more
detailed descriptions of PCT books, videos, order forms etc.

This introduction provides information about:

   Perceptual Control Theory (PCT): What it is
   Introductions to Perceptual Control Theory
   The Evolution of the Control Paradigm
   Demonstrating the Phenomenon of Control
   The Purpose of CSGnet
   CSGnet Participants
   Asking Questions
   Post Format
   The Control Systems Group
   Accessing and Subscribing to CSGnet
   Gopher and World-Wide Web
   On-line documents
   References
   Order Forms

   PERCEPTUAL CONTROL THEORY (PCT): WHAT IT IS

PCT offers a clear explanation for the pervasive phenomenon of
control, which is also known as purposeful behavior. Hierarchical
PCT (HPCT) outlines a hierarchical arrangement as a likely
organization of multiple control systems, which can explain the
purposeful behavior of living organisms.

PCT and HPCT were developed by William T. Powers, and introduced in
his 1973 book _Behavior: The Control of Perception_. (See
references and order forms, below). Powers shows us that the
engineering concept of control helps improve our understanding of
behavior, conflict, cooperation, and personal relationships. Just
as the in-depth explanatory theories of modern physical science
have helped us understand inanimate objects better than was
possible with experience and descriptive theories alone, the
in-depth explanations of PCT help us understand living organisms
better than has been possible with experience and descriptive
theories.

PCT focuses on how we look at and experience things, and the way
these perceptions are compared with experiences we want. The
difference produces action and physiology. Thus PCT explains how
thoughts become actions, feelings and results, and its principles
can be applied to any activity involving human experience.

PCT helps us understand people as they naturally are, just as
engineers understand physical phenomena as they naturally are. PCT
is remarkably simple, but like any other applied science, it
requires an understanding of basic principles and practice in their
application.

Much of the discussion on CSG-L reflects the rigorous "engineering
science" discipline of PCT and HPCT. Those who apply PCT and HPCT
to issues of personal relationships, education and management are
applying the basic principles to areas where they have not yet been
proven with scientific rigor, but seem to work well indeed.

  INTRODUCTIONS TO PERCEPTUAL CONTROL THEORY

Here are introductions by Bill and Mary Powers:

                 * * * * * * * *

  There have been two paradigms in the behavioral sciences since
  the 1600's. One was the idea that events impinging on organisms
  make them behave as they do. The other, which was developed in
  the 1930's, is PERCEPTUAL CONTROL THEORY (PCT). Perceptual
  Control Theory explains how organisms control what happens to
  them. This means all organisms from the amoeba to humankind. It
  explains why one organism can't control another without physical
  violence. It explains why people deprived of any major part of
  their ability to control soon become dysfunctional, lose interest
  in life, pine away and die. It explains what a goal is, how goals
  relate to action, how action affects perceptions and how
  perceptions define the reality in which we live and move and have
  our being. Perceptual Control Theory is the first scientific
  theory that can handle all these phenomena within a single,
  testable concept of how living systems work.

           William T. Powers, November 3, 1991

                 * * * * * * * *

  While the existence of control mechanisms and processes (such as
  feedback) in living systems is generally recognized, the
  implications of control organization go far beyond what is
  generally accepted. We believe that a fundamental characteristic
  of organisms is their ability to control; that they are, in fact,
  living control systems. To distinguish this approach from others
  using some version of control theory but forcing it to fit
  conventional approaches, we call ours Perceptual Control Theory,
  or PCT.

  PCT requires a major shift in thinking from the traditional
  approach: that what is controlled is not behavior, but
  perception. Modelling behavior as a dependent variable, as a
  response to stimuli, provides no explanation for the phenomenon
  of achieving consistent ends through varying means, and requires
  an extensive use of statistics to achieve modest (to the point of
  meaningless) correlations. Attempts to model behavior as planned
  and computed output can be demonstrated to require levels of
  precise calculation that are unobtainable in a physical system,
  and impossible in a real environment that is changing from one
  moment to the next. The PCT model views behavior as the means by
  which a perceived state of affairs is brought to and maintained
  at a reference state. This approach provides a physically
  plausible explanation for the consistency of outcomes and the
  variability of means.

  The PCT model has been used to simulate phenomena as diverse as
  bacterial chemotaxis, tracking a target, and behavior in crowds.
  In its elaborated form, a hierarchy of perceptual control systems
  (HPCT), it has lent itself to a computer simulation of tracking,
  including learning to track, and to new approaches to education,
  management, and psychotherapy.

  Control systems are not new in the life sciences. However,
  numerous misapprehensions exist, passed down from what was
  learned about control theory by non-engineers 40 or 50 years ago
  without further reference to newer developments or correction of
  initial misunderstandings. References in the literature to the
  desirability of positive feedback and the assertion that systems
  with feedback are slower than S-R systems are simply false, and
  concerns about stability are unfounded.

  The primary barrier to the adoption of PCT concepts is the
  belief--or hope--that control theory can simply be absorbed into
  the mainstream life sciences without disturbing the status quo.
  It is very hard to believe that one's training and life work, and
  that of one's mentors, and their mentors, must be fundamentally
  revised. Therefore, PCT appeals to those who feel some
  dissatisfaction with the status quo, or who are attracted to the
  idea of a generative model with broad application throughout the
  life sciences (plus AI and robotics). There are very few people
  working in PCT research. Much of its promise is still simply
  promise, and it meets resistance from all sides. It is
  frustrating but also tremendously exciting to be a part of the
  group who believe that they are participating in the birth of a
  true science of life.

           Mary Powers, November 1992

                 * * * * * * * *

  THE EVOLUTION OF THE CONTROL PARADIGM

The PCT paradigm originates in 1927, when an engineer named Harold
Black completed the technical analysis of closed loop control
systems. He was working with the negative feedback amplifier, which
is a control device. This led to a new engineering discipline and
the development of many purposeful machines. Purposeful machines
have built-in intent to achieve specified ends by variable means
under changing conditions.

The explanation for the phenomenon of control is the first
alternative to the linear cause-effect perspective ever proposed in
any science.

The first discussion of purposeful machines and people came in 1943
in a paper called: Behavior, Purpose and Teleology by Rosenblueth,
Wiener and Bigelow. This paper also argued that purpose belongs in
science as a real phenomenon in the present. Purpose does not mean
that somehow the future influences the present.

William T. (Bill) Powers developed PCT, beginning in the mid-50's.
In 1973 his book called "Behavior: the Control of Perception."
(often referred to as B:CP) was published. It is still the major
reference for PCT and discussion on CSG-L.

B:CP spells out a suggestion for a working model of how the human
brain and nervous system works. Our brain is a system that controls
its own perceptions. This view suggests explanations for many
previously mysterious aspects of how people interact with their
world.

Perceptual Control Theory has been accepted by independently
thinking psychologists, scientists, engineers and others. The
result is that an association has been formed (the Control System
Group), several books published, this CSGnet set up and that
several professors teach PCT in American universities today.

  DEMONSTRATING THE PHENOMENON OF CONTROL

Few scientists recognize or understand the phenomenon of control.
It is not well understood in important aspects even by many control
engineers. Yet the phenomenon of control, when it is recognized and
understood, provides a powerful enhancement to scientific
perspectives.

It is essential to recognize that control exists and deserves an
explanation before any of the discourse on CSGnet will make sense.

Please download the introductory computer demonstrations,
simulations and tutorials, beginning with "demo1". See "Gopher and
World-Wide Web" below for obtaining files via FTP, Gopher, and WWW.

  THE PURPOSE OF CSGnet

CSGnet provides a forum for development, use and testing of PCT.

  CSGnet PARTICIPANTS

Many interests and backgrounds are represented here. Psychology,
Sociology, Linguistics, Artificial Intelligence, Robotics, Social
Work, Neurology, Modeling and Testing. All are represented and
discussed. As of March 20, 1995 there were 146 individuals from 20
countries subscribed to CSGnet.

  ASKING QUESTIONS

Please introduce yourself with a statement of your professional
interests and background. It will help someone answer if you spell
out which demonstrations, introductory papers and references you
have taken the time to digest.

  POST FORMAT

When you are ready to introduce yourself and post to CSG-L, please
begin each post with your name and date of posting at the beginning
of the message itself, as shown here:

[Dag Forssell (950212 1600)]

This lets readers know who sent the message, and when (sometimes
very different from the automated datestamp). It provides a
convenient reference for replies. When you respond to a message,
please use this reference and quote only relevant parts of the
message you comment on.

  THE CONTROL SYSTEMS GROUP

The CSG is an organization of people in the behavioral, social, and
life sciences who see the potential in PCT for increased
understanding in their own fields and for the unification of
diverse and fragmented specialties.

Annual dues are $20 for full members and $5 for students.

The Twelfth North American Annual Meeting of the CSG will held in
1996 from July 17 to 21 at Northern Arizona University in
Flagstaff, Arizona. Shuttle service from the Phoenix airport to
Flagstaff will be available. There will be seven plenary meetings
(mornings and evenings), with afternoons, mealtimes, and late night
free for further discussion or recreation. Full details will be
available on CSGnet or by mail after April 1, 1996. The Second
Meeting of the European Control Systems Group (ECSG) will also be
held in 1996. Details to be arranged and posted on this net.

For membership information write:
CSG, c/o Mary Powers, 73 Ridge Place CR 510, Durango, CO 81301-8136
USA or send e-mail to powers_w@fortlewis.edu.

  ACCESSING AND SUBSCRIBING TO CSGnet

CSGnet can also be accessed via Usenet where it is listed as the
newsgroup "bit.sci.purposive-behavior" (NOTE: You may have to set
your default news server to news.cso.uiuc.edu to read this group.)

To subscribe to the listserv version of CSGnet, and learn about
options & commands, subscribers and archives, send a message to

listserv@vmd.cso.uiuc.edu

Message: (Comments: Not part of your message)

Subscribe CSG-L Firstname Lastname Institution (Your OWN name)
help (Basic introduction to commands)
info refcard (Comprehensive reference of commands)
set CSG-L digest * (Deliver one day's worth every morning)
set CSG-L repro (Get copy of your own postings)
set CSG-L ack (Receive acknowledgements when posting)
query CSG-L (Your mail status & options)
review CSG-L countries (Subscribers & addresses, by country)
index CSG-L (List of archive files available to you)
get CSG-L LOG9502B (Get archive for second week of Feb 1995
                           --shown here as an example only).

* The alternatives are:
set CSG-L mail (Get messages as they are posted)
set CSG-L nomail (Stop the mail temporarily)

The Bitnet address for the list server is listserv@uiucvmd.

To remove yourself from the listserv version of CSGnet, send a
message as follows to listserv@vmd.cso.uiuc.edu

Unsub CSG-L

For the "unsub" command to work, the command must be sent with the
same return address used for the original "subscribe" command.

Messages to the entire CSGnet community should be addressed to
CSG-L@vmd.cso.uiuc.edu

For more information about accessing CSGnet, contact Gary Cziko,
the network manager, at g-cziko@uiuc.edu

  GOPHER AND WORLD-WIDE WEB

A number of documents as well as MS-DOS and Mackintosh computer
programs can be obtained via Gopher and the World-Wide Web
(currently under construction).

To use a Gopher browser, connect to gopher.ed.uiuc.edu and follow
the path:

Higher Education Resources/
Professional societies & journals/
Control Systems Group

or from your favorite Gopher server follow the path:

Other Gopher and Information Servers/
North America/
USA/
illinois/
University of Ill.--College of Education/
Higher Education Resources/
Professional societies & journals/
Control Systems Group

The WWW address for the CSG homepage (under construction) is
http://www.ed.uiuc.edu/csg/ (don't forget the final slash).

  ON-LINE DOCUMENTS

A large collection of extracts from CSGnet discussions can be found
at on the World Wide Web at
http://www.ed.uiuc.edu/csg/documents/docindex.html. In addition,
extracts from selected published works can be found among the
references list below.

  REFERENCES

Here are some selected books, papers and computer programs on
Perceptual Control Theory. For a very complete list of CSG-related
publications, get the file biblio.pct from the fileserver as
described above. See also the "PCT Introduction and Resource Guide"
and order forms below.

                 * * * * * * * *

Bourbon, WT, KE Copeland, VR Dyer, WK Harman & BL Mosely (1990). On
the accuracy and reliability of predictions by control-system
theory. Perceptual and Motor Skills, vol 71, 1990, 1331-1338.
  The first of a 20-year series demonstrating the long-term
  reliability and stability of predictions generated by the PCT
  model.

Bourbon, W. Tom (In Press). Perceptual Control Theory. In: HL
Roitblat & J-A Meyer (eds.). Comparative approaches to cognitive
science. Cambridge, MA: MIT Press.
  Chapter surveys applications of PCT modeling by Bill Powers and
  Greg Williams (pointing, from the ARM/LITTLE MAN program); by
  Rick Marken and Bill Powers (movement "up a gradient" by E.
  coli), by Bill Powers, Clark Mcphail and Chuck Tucker (social
  movement and static formations, from the GATHERINGS program), and
  by Bourbon (tracking). The PCT model is contrasted with some of
  the mainstream models and theories presented at the workshop.

Cziko, Gary A. (1992). Purposeful behavior as the control of
perception: Implications for educational research. Educational
Researcher, 21(9), 10-18, 27.
  Introduction to PCT and implications for educational research.

Cziko, Gary A. (1992). Perceptual control theory: One threat to
educational research not (yet?) faced by Amundson, Serlin, and
Lehrer. Educational Researcher, 21(9), 25-27.
  Response to critics of previous article.

Cziko, Gary. (1995). Without miracles: Universal selection theory
and the second Darwinian evolution. Cambridge: MIT Press/A Bradford
Book.
     See Chapter 8, "Adapted Behavior as the Control of Perception"

Ford, Edward E. (1989). Freedom From Stress. Scottsdale AZ: Brandt
Publishing. A self-help book.
  PCT in a counseling framework.

Ford, Edward E. (1987). Love Guaranteed; A Better Marriage In 8
Weeks. Scottsdale AZ: Brandt Publishing.

Ford, Edward E. (1994). Discipline for Home and School. Scottsdale
AZ: Brandt Publishing.
  Teaches school personnel and parents how to deal effectively with
  children.

Forssell, Dag C., (1993). Perceptual Control: A New Management
Insight. In Engineering Management Journal, 5(4), 17-25.

Forssell, Dag C., (1994). Perceptual Control: Management Insight
for Problem Solving. In Engineering Management Journal, 6(3),
31-39.

Forssell, Dag C., (1995). Perceptual Control: Leading
Uncontrollable People. In Engineering Management Journal, 7(1), 38-
45.

Forssell, Dag C., (1994). Management and Leadership: Insight for
Effective Practice.
  A collection of articles (shown above) and working papers in book
  form introducing and applying PCT in the context of business and
  industry.

Forssell, Dag C. (Ed.), (1995). PCTdemos and PCTtexts. Two DOS
disks 1.44 MB 3 1/2". May be freely copied. Also available at the
WWW site shown above.
  PCTdemos holds eight different tutorial, simulation and
  demonstration programs with documentation. PCTtexts holds 3+ MB
  of essays, explanation, and debate.

Gibbons, Hugh. (1990). The Death of Jeffrey Stapleton: Exploring
the Way Lawyers Think. Concord, NH: Franklin Pierce Law Center.
  A text for law students using control theory.

Hershberger, Wayne. (Ed.). (1989). Volitional Action: Conation and
Control (Advances in Psychology No. 62). NY: North-Holland.
  16 of 25 articles on or about PCT.

Judd, Joel. (1992). Second Language Acquisition as the Control of
Nonprimary Linguistic Perception: A Critique of Research and
Theory. Unpublished doctoral dissertation, University of Illinois
at Champaign-Urbana. Dissertation Abstracts International, 53, (7),
#9236495.

Marken, Richard S. (Ed.). (1990). Purposeful Behavior: The control
theory approach. American Behavioral Scientist, 34(1). (Thousand
Oaks, CA: Sage Publications).
  11 articles on control theory.

Marken, Richard S. (1992). Mind Readings: Experimental Studies of
Purpose. NC: New View.
  Research papers exploring control.

McClelland, Kent. 1994. Perceptual Control and Social Power.
Sociological Perspectives 37(4):461-496.

McClelland, Kent. On Cooperatively Controlled Perceptions and
Social order. Available from the author, Dept. of Sociology,
Grinnell College, Grinnell IOWA 50112 USA.

McPhail, Clark. (1990). The Myth of the Madding Crowd. New York:
Aldine de Gruyter.
  Introduces control theory to explain group behavior.

McPhail, Clark., Powers, William T., & Tucker, Charles W. (1992).
Simulating individual and collective action In temporary
gatherings. Social Science Computer Review, 10(1), 1-28.
  Computer simulation of control systems in groups.

Petrie, Hugh G. (1981). The Dilemma of Inquiry and Learning.
Chicago: University of Chicago Press.

Powers, William T. (1973). Behavior: The Control of Perception.
Hawthorne, NY: Aldine DeGruyter.
  The basic text.

Powers, William T., The Nature of Robots:
  1 Defining Behavior BYTE 4(6), June 1979, p132-144, 7 pages.
  2 Simulated Control System, BYTE 4(7), July, 134-152, 12p.
  3 A Closer Look at Human Behavior, BYTE 4(8), Aug, 94-116, 16p.
  4 Looking for Controlled Variables, BYTE 4(8), Sep 96-112, 13p.

Powers, William T. (1989). Living Control Systems: Selected Papers.
NC: New View.
  Previously published papers, 1960-1988.

Powers, William T. (1992). Living Control Systems II: Selected
Papers. NC: New View.
  Previously unpublished papers, 1959-1990

Richardson, George P. (1991). Feedback Thought in Social Science
and Systems Theory. Philadelphia: University of Pennsylvania Press.
  A review of systems thinking, including PCT.

Robertson, Richard J. and Powers, William T. (Eds.). (1990).
Introduction to Modern Psychology: The Control Theory View. NC: New
View.
  College-level text.

Runkel, Philip J. (1990). Casting Nets and Testing Specimens. New
York: Praeger.
  When statistics are appropriate; when models are required.

                 * * * * * * * *

  ORDER FORMS

  A free 20 page PCT Resource Guide with introductions and more
  detail on the references listed above and a few more --
  publishers, books, articles, videos, seminars, and the DOS
  demonstration disk -- may be obtained by sending a note to:

           PCT Introduction and Resource Guide
           Dag Forssell
           23903 Via Flamenco
           Valencia, California, 91355-2808 USA.

The PCT Introduction and Resource Guide is also available in ASCII
format from the WWW site shown above.

Order forms in the Guide are reproduced below without descriptions.
All prices current as of April, 1995.

···

------------------------------------------------------------------
Purposeful Leadership: Dag Forssell Telephone: (805) 254-1195
23903 Via Flamenco, Valencia, CA 91355-2808 USA Fax:(805) 254-7956

___ ea Management and Leadership: Insight for ... @ $20.00 ______
___ ea PCTdemos and PCTtexts. DOS. 3 1/2" disks. @ $10.00 ______
___ ea Rubber Band Demo. Video & Script 63 minutes @ $20.00 ______
___ ea PCT supports TQM. Video 117 minutes @ $20.00 ______
___ ea PCT @ AERA 1995. Video 120 minutes @ $10.00 ______
___ ea 1993 CSG conference. 3 videos, 18 hours. @ $30.00 ______
___ ea 1994 CSG conference. 3 videos, 16 hours. @ $30.00 ______
___ ea Freedom From Stress. Book by Ed Ford @ $10.00 ______
___ ea PCT Introduction and Resource Guide Free _N/C__
       California residents please add 8.25% sales tax ______
       Shipping & Handling (world wide) @ $5.00 _5.00_
       Prepaid: Check, money order Total ______

NAME _____________________________ Phone__________________________

ADDRESS __________________________________________________________

__________________________________________________________________

------------------------------------------------------------------
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10209 North 56th Street, Scottsdale, AZ 85253-1130 USA

___ ea Freedom From Stress, Book @ $10.00 _______
___ ea Love Guaranteed, Book @ $ 9.00 _______
___ ea Love Guaranteed, Video @ $20.00 _______
___ ea Discipline for Home and School, Book @ $10.00 _______
       Arizona residents please add sales tax, 6%. Tax _______
       Shipping & Handling (world wide) @ $3.50 _3.50__
       Prepaid: Check, money order Total _______

NAME______________________________ Phone__________________________

ADDRESS __________________________________________________________

__________________________________________________________________

-----------------------------------------------------------------

New View: Fred Good Telephone: (919) 942-8491
P.O. Box 3021 Chapel Hill, NC 27515-3021 USA Fax: (919) 942-3760

___ ea BEHAVIOR: THE CONTROL OF PERCEPTION @ $41.95 _______
___ ea INTRODUCTION TO MODERN PSYCHOLOGY @ $25.00 _______
___ ea LIVING CONTROL SYSTEMS @ $16.50 _______
___ ea LIVING CONTROL SYSTEMS II @ $22.00 _______
___ ea MIND READINGS @ $18.00 _______
___ ea PCT Introduction and Resource Guide Free _N/C__
       North Carolina residents add sales tax, 6%. Tax _______
       Shipping & Handling (see schedule below) _______
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NEW VIEW Shipping:

Up to $25 $4
$25.01-$50 $5
$50.01-$100 $6
Over $100 6% of subtotal
UPS second day $10 + 10% of subtotal

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and Mexico shipped air mail: $5 plus 10% of subtotal. All other
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Checks must be drawn in US funds.

------------------------------------------------------------------
Journal Marketing, Sage Publications Phone orders: (805) 499-0721
2455 Teller Rd, Newbury Park, CA 91320 USA Fax: (805) 499-0871

  American Behavioral Scientist, Volume 34, Number 1 Sept/Oct 1990
       Stock number 201238 Richard S. Marken, Editor
       Purposeful Behavior; The Control Theory Approach,
___ ea Price for individuals and companies: @ $11.20 _______
___ ea Price for institutions and libraries: @ $22.40 _______
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                            - END -

INTROCSG.NET

This file is posted every month to CSG-L.

       INTRODUCTION TO PERCEPTUAL CONTROL THEORY (PCT)
               THE CONTROL SYSTEMS GROUP (CSG)
    AND THE CONTROL SYSTEMS GROUP NETWORK (CSG-L or CSGnet)

          Prepared by Dag Forssell with Gary Cziko
                  Updated September 30, 1995

This is an introduction to Perceptual Control Theory (PCT), and the
discussion group CSG-L. CSG-L is listed on Usenet as the newsgroup
"bit.sci.purposive-behavior." This introduction is posted at the
beginning of each month for newcomers to CSG-L and the newsgroup.

A complementary, more detailed "PCT Introduction and Resource
Guide" is available from the WWW server shown below (file
RESOURCE.PCT, 75 KB), or by mail (20 pages) as shown in the section
on references and order forms. It features the book jacket for
_Behavior: The Control of Perception_; two short essays by Bill
Powers: _An essay on the obvious_ and _Things I'd like to say if
they wouldn't think I am a nut_, which deal with the requirements
for and consequences of applying physical science to the field of
psychology; the foreword for _Living Control Systems II_ by Tom
Bourbon and more; plus more detailed descriptions of PCT books,
videos, order forms etc.

This introduction provides information about:

   Perceptual Control Theory (PCT): What it is
   Introductions to Perceptual Control Theory
   The Evolution of the Control Paradigm
   Demonstrating the Phenomenon of Control
   The Purpose of CSGnet
   CSGnet Participants
   Asking Questions
   Post Format
   The Control Systems Group
   Accessing and Subscribing to CSGnet
   Gopher and World-Wide Web
   On-line documents
   References
   Order Forms

   PERCEPTUAL CONTROL THEORY (PCT): WHAT IT IS

PCT offers a clear explanation for the pervasive phenomenon of
control, which is also known as purposeful behavior. Hierarchical
PCT (HPCT) outlines a hierarchical arrangement as a likely
organization of multiple control systems, which can explain the
purposeful behavior of living organisms.

PCT and HPCT were developed by William T. Powers, and introduced in
his 1973 book _Behavior: The Control of Perception_. (See
references and order forms, below). Powers shows us that the
engineering concept of control helps improve our understanding of
behavior, conflict, cooperation, and personal relationships. Just
as the in-depth explanatory theories of modern physical science
have helped us understand inanimate objects better than was
possible with experience and descriptive theories alone, the
in-depth explanations of PCT help us understand living organisms
better than has been possible with experience and descriptive
theories.

PCT focuses on how we look at and experience things, and the way
these perceptions are compared with experiences we want. The
difference produces action and physiology. Thus PCT explains how
thoughts become actions, feelings and results, and its principles
can be applied to any activity involving human experience.

PCT helps us understand people as they naturally are, just as
engineers understand physical phenomena as they naturally are. PCT
is remarkably simple, but like any other applied science, it
requires an understanding of basic principles and practice in their
application.

Much of the discussion on CSG-L reflects the rigorous "engineering
science" discipline of PCT and HPCT. Those who apply PCT and HPCT
to issues of personal relationships, education and management are
applying the basic principles to areas where they have not yet been
proven with scientific rigor, but seem to work well indeed.

  INTRODUCTIONS TO PERCEPTUAL CONTROL THEORY

Here are introductions by Bill and Mary Powers:

                 * * * * * * * *

  There have been two paradigms in the behavioral sciences since
  the 1600's. One was the idea that events impinging on organisms
  make them behave as they do. The other, which was developed in
  the 1930's, is PERCEPTUAL CONTROL THEORY (PCT). Perceptual
  Control Theory explains how organisms control what happens to
  them. This means all organisms from the amoeba to humankind. It
  explains why one organism can't control another without physical
  violence. It explains why people deprived of any major part of
  their ability to control soon become dysfunctional, lose interest
  in life, pine away and die. It explains what a goal is, how goals
  relate to action, how action affects perceptions and how
  perceptions define the reality in which we live and move and have
  our being. Perceptual Control Theory is the first scientific
  theory that can handle all these phenomena within a single,
  testable concept of how living systems work.

           William T. Powers, November 3, 1991

                 * * * * * * * *

  While the existence of control mechanisms and processes (such as
  feedback) in living systems is generally recognized, the
  implications of control organization go far beyond what is
  generally accepted. We believe that a fundamental characteristic
  of organisms is their ability to control; that they are, in fact,
  living control systems. To distinguish this approach from others
  using some version of control theory but forcing it to fit
  conventional approaches, we call ours Perceptual Control Theory,
  or PCT.

  PCT requires a major shift in thinking from the traditional
  approach: that what is controlled is not behavior, but
  perception. Modelling behavior as a dependent variable, as a
  response to stimuli, provides no explanation for the phenomenon
  of achieving consistent ends through varying means, and requires
  an extensive use of statistics to achieve modest (to the point of
  meaningless) correlations. Attempts to model behavior as planned
  and computed output can be demonstrated to require levels of
  precise calculation that are unobtainable in a physical system,
  and impossible in a real environment that is changing from one
  moment to the next. The PCT model views behavior as the means by
  which a perceived state of affairs is brought to and maintained
  at a reference state. This approach provides a physically
  plausible explanation for the consistency of outcomes and the
  variability of means.

  The PCT model has been used to simulate phenomena as diverse as
  bacterial chemotaxis, tracking a target, and behavior in crowds.
  In its elaborated form, a hierarchy of perceptual control systems
  (HPCT), it has lent itself to a computer simulation of tracking,
  including learning to track, and to new approaches to education,
  management, and psychotherapy.

  Control systems are not new in the life sciences. However,
  numerous misapprehensions exist, passed down from what was
  learned about control theory by non-engineers 40 or 50 years ago
  without further reference to newer developments or correction of
  initial misunderstandings. References in the literature to the
  desirability of positive feedback and the assertion that systems
  with feedback are slower than S-R systems are simply false, and
  concerns about stability are unfounded.

  The primary barrier to the adoption of PCT concepts is the
  belief--or hope--that control theory can simply be absorbed into
  the mainstream life sciences without disturbing the status quo.
  It is very hard to believe that one's training and life work, and
  that of one's mentors, and their mentors, must be fundamentally
  revised. Therefore, PCT appeals to those who feel some
  dissatisfaction with the status quo, or who are attracted to the
  idea of a generative model with broad application throughout the
  life sciences (plus AI and robotics). There are very few people
  working in PCT research. Much of its promise is still simply
  promise, and it meets resistance from all sides. It is
  frustrating but also tremendously exciting to be a part of the
  group who believe that they are participating in the birth of a
  true science of life.

           Mary Powers, November 1992

                 * * * * * * * *

  THE EVOLUTION OF THE CONTROL PARADIGM

The PCT paradigm originates in 1927, when an engineer named Harold
Black completed the technical analysis of closed loop control
systems. He was working with the negative feedback amplifier, which
is a control device. This led to a new engineering discipline and
the development of many purposeful machines. Purposeful machines
have built-in intent to achieve specified ends by variable means
under changing conditions.

The explanation for the phenomenon of control is the first
alternative to the linear cause-effect perspective ever proposed in
any science.

The first discussion of purposeful machines and people came in 1943
in a paper called: Behavior, Purpose and Teleology by Rosenblueth,
Wiener and Bigelow. This paper also argued that purpose belongs in
science as a real phenomenon in the present. Purpose does not mean
that somehow the future influences the present.

William T. (Bill) Powers developed PCT, beginning in the mid-50's.
In 1973 his book called "Behavior: the Control of Perception."
(often referred to as B:CP) was published. It is still the major
reference for PCT and discussion on CSG-L.

B:CP spells out a suggestion for a working model of how the human
brain and nervous system works. Our brain is a system that controls
its own perceptions. This view suggests explanations for many
previously mysterious aspects of how people interact with their
world.

Perceptual Control Theory has been accepted by independently
thinking psychologists, scientists, engineers and others. The
result is that an association has been formed (the Control System
Group), several books published, this CSGnet set up and that
several professors teach PCT in American universities today.

  DEMONSTRATING THE PHENOMENON OF CONTROL

Few scientists recognize or understand the phenomenon of control.
It is not well understood in important aspects even by many control
engineers. Yet the phenomenon of control, when it is recognized and
understood, provides a powerful enhancement to scientific
perspectives.

It is essential to recognize that control exists and deserves an
explanation before any of the discourse on CSGnet will make sense.

Please download the introductory computer demonstrations,
simulations and tutorials, beginning with "demo1". See "Gopher and
World-Wide Web" below for obtaining files via FTP, Gopher, and WWW.

  THE PURPOSE OF CSGnet

CSGnet provides a forum for development, use and testing of PCT.

  CSGnet PARTICIPANTS

Many interests and backgrounds are represented here. Psychology,
Sociology, Linguistics, Artificial Intelligence, Robotics, Social
Work, Neurology, Modeling and Testing. All are represented and
discussed. As of March 20, 1995 there were 146 individuals from 20
countries subscribed to CSGnet.

  ASKING QUESTIONS

Please introduce yourself with a statement of your professional
interests and background. It will help someone answer if you spell
out which demonstrations, introductory papers and references you
have taken the time to digest.

  POST FORMAT

When you are ready to introduce yourself and post to CSG-L, please
begin each post with your name and date of posting at the beginning
of the message itself, as shown here:

[Dag Forssell (950212 1600)]

This lets readers know who sent the message, and when (sometimes
very different from the automated datestamp). It provides a
convenient reference for replies. When you respond to a message,
please use this reference and quote only relevant parts of the
message you comment on.

  THE CONTROL SYSTEMS GROUP

The CSG is an organization of people in the behavioral, social, and
life sciences who see the potential in PCT for increased
understanding in their own fields and for the unification of
diverse and fragmented specialties.

Annual dues are $20 for full members and $5 for students.

The Twelfth North American Annual Meeting of the CSG will held in
1996 from July 17 to 21 at Northern Arizona University in
Flagstaff, Arizona. Shuttle service from the Phoenix airport to
Flagstaff will be available. There will be seven plenary meetings
(mornings and evenings), with afternoons, mealtimes, and late night
free for further discussion or recreation. Full details will be
available on CSGnet or by mail after April 1, 1996. The Second
Meeting of the European Control Systems Group (ECSG) will also be
held in 1996. Details to be arranged and posted on this net.

For membership information write:
CSG, c/o Mary Powers, 73 Ridge Place CR 510, Durango, CO 81301-8136
USA or send e-mail to powers_w@fortlewis.edu.

  ACCESSING AND SUBSCRIBING TO CSGnet

CSGnet can also be accessed via Usenet where it is listed as the
newsgroup "bit.sci.purposive-behavior" (NOTE: You may have to set
your default news server to news.cso.uiuc.edu to read this group.)

To subscribe to the listserv version of CSGnet, and learn about
options & commands, subscribers and archives, send a message to

listserv@vmd.cso.uiuc.edu

Message: (Comments: Not part of your message)

Subscribe CSG-L Firstname Lastname Institution (Your OWN name)
help (Basic introduction to commands)
info refcard (Comprehensive reference of commands)
set CSG-L digest * (Deliver one day's worth every morning)
set CSG-L repro (Get copy of your own postings)
set CSG-L ack (Receive acknowledgements when posting)
query CSG-L (Your mail status & options)
review CSG-L countries (Subscribers & addresses, by country)
index CSG-L (List of archive files available to you)
get CSG-L LOG9502B (Get archive for second week of Feb 1995
                           --shown here as an example only).

* The alternatives are:
set CSG-L mail (Get messages as they are posted)
set CSG-L nomail (Stop the mail temporarily)

The Bitnet address for the list server is listserv@uiucvmd.

To remove yourself from the listserv version of CSGnet, send a
message as follows to listserv@vmd.cso.uiuc.edu

Unsub CSG-L

For the "unsub" command to work, the command must be sent with the
same return address used for the original "subscribe" command.

Messages to the entire CSGnet community should be addressed to
CSG-L@vmd.cso.uiuc.edu

For more information about accessing CSGnet, contact Gary Cziko,
the network manager, at g-cziko@uiuc.edu

  GOPHER AND WORLD-WIDE WEB

A number of documents as well as MS-DOS and Mackintosh computer
programs can be obtained via Gopher and the World-Wide Web
(currently under construction).

To use a Gopher browser, connect to gopher.ed.uiuc.edu and follow
the path:

Higher Education Resources/
Professional societies & journals/
Control Systems Group

or from your favorite Gopher server follow the path:

Other Gopher and Information Servers/
North America/
USA/
illinois/
University of Ill.--College of Education/
Higher Education Resources/
Professional societies & journals/
Control Systems Group

The WWW address for the CSG homepage (under construction) is
http://www.ed.uiuc.edu/csg/ (don't forget the final slash).

  ON-LINE DOCUMENTS

A large collection of extracts from CSGnet discussions can be found
at on the World Wide Web at
http://www.ed.uiuc.edu/csg/documents/docindex.html. In addition,
extracts from selected published works can be found among the
references list below.

  REFERENCES

Here are some selected books, papers and computer programs on
Perceptual Control Theory. For a very complete list of CSG-related
publications, get the file biblio.pct from the fileserver as
described above. See also the "PCT Introduction and Resource Guide"
and order forms below.

                 * * * * * * * *

Bourbon, WT, KE Copeland, VR Dyer, WK Harman & BL Mosely (1990). On
the accuracy and reliability of predictions by control-system
theory. Perceptual and Motor Skills, vol 71, 1990, 1331-1338.
  The first of a 20-year series demonstrating the long-term
  reliability and stability of predictions generated by the PCT
  model.

Bourbon, W. Tom (In Press). Perceptual Control Theory. In: HL
Roitblat & J-A Meyer (eds.). Comparative approaches to cognitive
science. Cambridge, MA: MIT Press.
  Chapter surveys applications of PCT modeling by Bill Powers and
  Greg Williams (pointing, from the ARM/LITTLE MAN program); by
  Rick Marken and Bill Powers (movement "up a gradient" by E.
  coli), by Bill Powers, Clark Mcphail and Chuck Tucker (social
  movement and static formations, from the GATHERINGS program), and
  by Bourbon (tracking). The PCT model is contrasted with some of
  the mainstream models and theories presented at the workshop.

Cziko, Gary A. (1992). Purposeful behavior as the control of
perception: Implications for educational research. Educational
Researcher, 21(9), 10-18, 27.
  Introduction to PCT and implications for educational research.

Cziko, Gary A. (1992). Perceptual control theory: One threat to
educational research not (yet?) faced by Amundson, Serlin, and
Lehrer. Educational Researcher, 21(9), 25-27.
  Response to critics of previous article.

Cziko, Gary. (1995). Without miracles: Universal selection theory
and the second Darwinian evolution. Cambridge: MIT Press/A Bradford
Book.
     See Chapter 8, "Adapted Behavior as the Control of Perception"

Ford, Edward E. (1989). Freedom From Stress. Scottsdale AZ: Brandt
Publishing. A self-help book.
  PCT in a counseling framework.

Ford, Edward E. (1987). Love Guaranteed; A Better Marriage In 8
Weeks. Scottsdale AZ: Brandt Publishing.

Ford, Edward E. (1994). Discipline for Home and School. Scottsdale
AZ: Brandt Publishing.
  Teaches school personnel and parents how to deal effectively with
  children.

Forssell, Dag C., (1993). Perceptual Control: A New Management
Insight. In Engineering Management Journal, 5(4), 17-25.

Forssell, Dag C., (1994). Perceptual Control: Management Insight
for Problem Solving. In Engineering Management Journal, 6(3),
31-39.

Forssell, Dag C., (1995). Perceptual Control: Leading
Uncontrollable People. In Engineering Management Journal, 7(1), 38-
45.

Forssell, Dag C., (1994). Management and Leadership: Insight for
Effective Practice.
  A collection of articles (shown above) and working papers in book
  form introducing and applying PCT in the context of business and
  industry.

Forssell, Dag C. (Ed.), (1995). PCTdemos and PCTtexts. Two DOS
disks 1.44 MB 3 1/2". May be freely copied. Also available at the
WWW site shown above.
  PCTdemos holds eight different tutorial, simulation and
  demonstration programs with documentation. PCTtexts holds 3+ MB
  of essays, explanation, and debate.

Gibbons, Hugh. (1990). The Death of Jeffrey Stapleton: Exploring
the Way Lawyers Think. Concord, NH: Franklin Pierce Law Center.
  A text for law students using control theory.

Hershberger, Wayne. (Ed.). (1989). Volitional Action: Conation and
Control (Advances in Psychology No. 62). NY: North-Holland.
  16 of 25 articles on or about PCT.

Judd, Joel. (1992). Second Language Acquisition as the Control of
Nonprimary Linguistic Perception: A Critique of Research and
Theory. Unpublished doctoral dissertation, University of Illinois
at Champaign-Urbana. Dissertation Abstracts International, 53, (7),
#9236495.

Marken, Richard S. (Ed.). (1990). Purposeful Behavior: The control
theory approach. American Behavioral Scientist, 34(1). (Thousand
Oaks, CA: Sage Publications).
  11 articles on control theory.

Marken, Richard S. (1992). Mind Readings: Experimental Studies of
Purpose. NC: New View.
  Research papers exploring control.

McClelland, Kent. 1994. Perceptual Control and Social Power.
Sociological Perspectives 37(4):461-496.

McClelland, Kent. On Cooperatively Controlled Perceptions and
Social order. Available from the author, Dept. of Sociology,
Grinnell College, Grinnell IOWA 50112 USA.

McPhail, Clark. (1990). The Myth of the Madding Crowd. New York:
Aldine de Gruyter.
  Introduces control theory to explain group behavior.

McPhail, Clark., Powers, William T., & Tucker, Charles W. (1992).
Simulating individual and collective action In temporary
gatherings. Social Science Computer Review, 10(1), 1-28.
  Computer simulation of control systems in groups.

Petrie, Hugh G. (1981). The Dilemma of Inquiry and Learning.
Chicago: University of Chicago Press.

Powers, William T. (1973). Behavior: The Control of Perception.
Hawthorne, NY: Aldine DeGruyter.
  The basic text.

Powers, William T., The Nature of Robots:
  1 Defining Behavior BYTE 4(6), June 1979, p132-144, 7 pages.
  2 Simulated Control System, BYTE 4(7), July, 134-152, 12p.
  3 A Closer Look at Human Behavior, BYTE 4(8), Aug, 94-116, 16p.
  4 Looking for Controlled Variables, BYTE 4(8), Sep 96-112, 13p.

Powers, William T. (1989). Living Control Systems: Selected Papers.
NC: New View.
  Previously published papers, 1960-1988.

Powers, William T. (1992). Living Control Systems II: Selected
Papers. NC: New View.
  Previously unpublished papers, 1959-1990

Richardson, George P. (1991). Feedback Thought in Social Science
and Systems Theory. Philadelphia: University of Pennsylvania Press.
  A review of systems thinking, including PCT.

Robertson, Richard J. and Powers, William T. (Eds.). (1990).
Introduction to Modern Psychology: The Control Theory View. NC: New
View.
  College-level text.

Runkel, Philip J. (1990). Casting Nets and Testing Specimens. New
York: Praeger.
  When statistics are appropriate; when models are required.

                 * * * * * * * *

  ORDER FORMS

  A free 20 page PCT Resource Guide with introductions and more
  detail on the references listed above and a few more --
  publishers, books, articles, videos, seminars, and the DOS
  demonstration disk -- may be obtained by sending a note to:

           PCT Introduction and Resource Guide
           Dag Forssell
           23903 Via Flamenco
           Valencia, California, 91355-2808 USA.

The PCT Introduction and Resource Guide is also available in ASCII
format from the WWW site shown above.

Order forms in the Guide are reproduced below without descriptions.
All prices current as of April, 1995.

···

------------------------------------------------------------------
Purposeful Leadership: Dag Forssell Telephone: (805) 254-1195
23903 Via Flamenco, Valencia, CA 91355-2808 USA Fax:(805) 254-7956

___ ea Management and Leadership: Insight for ... @ $20.00 ______
___ ea PCTdemos and PCTtexts. DOS. 3 1/2" disks. @ $10.00 ______
___ ea Rubber Band Demo. Video & Script 63 minutes @ $20.00 ______
___ ea PCT supports TQM. Video 117 minutes @ $20.00 ______
___ ea PCT @ AERA 1995. Video 120 minutes @ $10.00 ______
___ ea 1993 CSG conference. 3 videos, 18 hours. @ $30.00 ______
___ ea 1994 CSG conference. 3 videos, 16 hours. @ $30.00 ______
___ ea Freedom From Stress. Book by Ed Ford @ $10.00 ______
___ ea PCT Introduction and Resource Guide Free _N/C__
       California residents please add 8.25% sales tax ______
       Shipping & Handling (world wide) @ $5.00 _5.00_
       Prepaid: Check, money order Total ______

NAME _____________________________ Phone__________________________

ADDRESS __________________________________________________________

__________________________________________________________________

------------------------------------------------------------------
Brandt Publishing: Edward E. Ford Telephone & Fax: (602) 991-4860
10209 North 56th Street, Scottsdale, AZ 85253-1130 USA

___ ea Freedom From Stress, Book @ $10.00 _______
___ ea Love Guaranteed, Book @ $ 9.00 _______
___ ea Love Guaranteed, Video @ $20.00 _______
___ ea Discipline for Home and School, Book @ $10.00 _______
       Arizona residents please add sales tax, 6%. Tax _______
       Shipping & Handling (world wide) @ $3.50 _3.50__
       Prepaid: Check, money order Total _______

NAME______________________________ Phone__________________________

ADDRESS __________________________________________________________

__________________________________________________________________

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New View: Fred Good Telephone: (919) 942-8491
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Journal Marketing, Sage Publications Phone orders: (805) 499-0721
2455 Teller Rd, Newbury Park, CA 91320 USA Fax: (805) 499-0871

  American Behavioral Scientist, Volume 34, Number 1 Sept/Oct 1990
       Stock number 201238 Richard S. Marken, Editor
       Purposeful Behavior; The Control Theory Approach,
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