How Perceptual Control Theory Began:

A Personal History
Mary A. Powers

    The beginnings of PCT lie in two major developments of the 1920s and 1930s:  H. S. Black's concept of negative-feedback control in electronics and Walter B. Cannon's concept of homeostasis in biology.  These were brought together in the early 1940s, primarily by Norbert Wiener, a mathematician, Julian Bigelow, an engineer, and Arturo Rosenblueth, a co-worker with Cannon.  In 1943, they published the first paper relating engineering control theory to neurophysiology.

    Although Wiener called his 1948 book Cybernetics, or Control and Communication in the Animal and the Machine and believed in the importance of control theory as a key to explaining some phenomena of living systems, he was far more interested in communication engineering and information theory.  This bias was shared by the participants in the 10 Macy Conferences that preceded and followed the 1948 publication of Cybernetics.  Many of the people who attended these conferences were prominent figures in the life, social, and behavioral sciences, mathematics, physics, and philosophy.  Though officially titled "Cybernetics:  Circular Causal and Feedback Mechanisms in Biological and Social Systems," the meetings were primarily concerned with issues of information and communication.

    Enter Bill Powers, an ex-Navy electronic tech and college physics major in his 20s (hardly the sort of person who got invited to the Macy Conferences) who had then what he has now:  an irresistable urge, when confronted with something unfamiliar but interesting, to grab a pencil and a piece of paper and start figuring it out.  What was interesting to him in Cybernetics was not communication, but rather the idea that the nervous system seemed to be a control system.  He thought this was an enormously exciting idea, and he couldn't wait to see where the big scientific guns and gurus would carry it.  Because he couldn't wait, he started figuring it out for himself, but he was sure for many years that someone far more competent than he would be coming along with a more extensive and profound analysis.  That someone, we now know with 20-20 hindsight, turned out to be himself, 20,30, and now 40 years later.

    Why Bill Powers?  My purpose here is to suggest a few of the variety of characteristics and circumstances that made him uniquely the person to develop PCT.  Since he is a private person, I intend to avoid getting too personal, with the one exception that for the rest of this paper I'm going to call him Bill.

    One place to begin is with the satisfaction Bill has always found in figuring out how things work, as mentioned above.  This contributed to a professional career at a technical level, with little aspiration to rise beyond the actual hands-on design and construction of control systems and development of computer software into the heady realms of administration and paperwork.  And his real career lay elsewhere—since working at the lower levels of an organization means, usually, being able to walk out the door at five o'clock and leave it all behind, the evenings and weekends that others might have spent furthering their professional ambitions were free for PCT.

    But sticking to the technical level also meant looking at a lot of emperors and finding them naked.  There is a good deal of difference between talking about control systems metaphorically, philosophically, and theoretically, and dealing with them on a practical basis, when you're in there soldering wires and making the damned things work.  And Bill made a number of control systems work very nicely indeed.

    While this sort of experience contributed to the solidity of the foundations of PCT, PCT at the same time contributed to Bill's successful design of control systems:  he would imagine "taking the point of view" of the control system he was designing—if I were this system, what would I be able to perceive, what would I need to perceive, what would "really" be going on?  This worked so well that he was convinced he was cheating, fudging over gaps in his technical expertise by using control theory as he was developing it to explain living systems (of course one person's cheating is another person's insight).

    Another circumstance fostering Bill's approach to living control systems was his coming of age in the era of analog computers.  The digital computer as a metaphor for the workings of the nervous system was immediately more attractive to many than the telephone switchboard it replaced, but in Bill's eyes, it is false at its base.  His programs, although digital, are designed to simulate the actual analog functions of the brain, not, as in Artificial Intelligence, to produce brain-like results by whatever means.  The contributions his analog models might make to neuroscience have yet to be explored.

    While Bill wanted his model to be plausible and workable from the physiological ground up, his main interest was psychology.  What he knew of psychology when he began was whatever was taught in undergraduate courses around 1950.  Behaviorism held the high ground as far as psychology as a science was concerned.  The therapeutic community was largely Freudian, with a dash of humanistic psychology—Carl Rogers and Fritz Perls, and later Abraham Maslow.  The treatments available for psychosis were lobotomies and electric shock.  Bill was interested in psychology for personal reasons, as almost everyone is, and like many young engineers and other technically inclined people, he discovered what seemed to be a far more fruitful approach in the pages of what for many of us was our favorite magazine, Astounding Science Fiction.  Many people were drawn to Dianetics because, unlike behaviorism, it didn't try to do away with the mind; in fact, all the action was in the mind, accessing and dealing with memories, in a very straightforward and routinized manner.  There was an appealing technical flavor to it.  Like others who went into Dianetics, Bill got out when L. Ron Hubbard's grandiosity, greed, and paranoia turned off youthful enthusiasm, and when it seemed that this "new science of the mind" was not all that it was cracked up to be.

    Soon, the first wave of disillusioned Dianetikers went back to work or school and went on with their lives (I kept running into them at the University of Chicago in the early '50s, and there are four—that I know of—alive and well in the CSG).  Bill, who had read Cybernetics by that time and thought it to be a much more promising approach than Dianetics had turned out to be, went to work as a medical physicist, and he discovered to his delight that his bosses knew about, used, designed, and could teach him about control systems.  This means he did not approach the subject of living systems from the point of view of a control engineer, but rather as a student of control theory, applying what he was learning to both artificial and living systems at the same time.  This, I think, is the source of his realization that the reference signal, which in artificial systems is set externally to the system and labelled "input," is, in living systems, internal, and not an externally accessible input at all.

    Together with Bob Clark, another physicist, and later Bob McFarland, a psychologist, the first model of hierarchical living control systems was worked out.  It was published in 1960 as "A General Feedback Theory of Human Behavior," which presented a six-level hierarchical model.  By this time, Bill had left his job and begun graduate work in psychology at Northwestern University, and the association with Clark and McFarland ended.  The graduate work ended after one year, done in by total incomprehension on the part of the faculty as to what on earth Bill's master's thesis proposal was about, by wifely financial panic, and by an appealing job offer from the Northwestern astronomy department.

    "Feedback theory" was the name of the game for many more years, as a book slowly took shape, was dropped into the wastebasket, was written again, and then again.  As this went on, the emphasis shifted from the one immediately obvious component that makes control systems unique, namely feedback, to the overall system of which feedback is a part, and ultimately to that aspect of a living control system that makes it so radically different and so difficult to understand, the control of perception.  The only possible way to know what is happening, or what one is doing, or the effects of either on the other, is by perception.

    How does a person entirely alone develop a science, without money, a lab, or colleagues?  One answer, of course, is that all the equipment was readily at hand.  Between children, a dog, a clunky computer, and above all, himself, there was more than enough to observe and think about.  The nature of much of that observation was unique, however, and involved a form of introspection in which one does not think about thoughts, but about what one is seeing:  What perceptions are necessary to see an object, or movement?  From what perceptions does logic emerge, or principles?  Thus the six levels of 1960 became nine by 1972, and they now number 11.  Bill is the first to admit that the levels he sees are personal, and possibly idiosyncratic, and it is with some dismay that he sees them taken as a final word on the subject, copied down and memorized.  But the main point here is that the levels, and much else about PCT, were derived from experience; the theory had to explain not just the performance of subjects, of others, but how the world looks from the only point of view available to anyone, from the inside.

    The main thing that Bill has been able to bring to his work, then and now, is a mind with no strings attached except his own initial feeling that control theory could answer some of his questions.  It is from that stance that he has read books, taken courses, and otherwise absorbed what was already available in the life sciences.  Learning what other people have done has never meant accepting either their premises or their conclusions.  As an outsider, he has never had to conform to any particular school of thought or please any particular community of scholars.  When confronted with such pressure (as with his master's thesis), he has simply walked away and continued on his own path.

    I think it took many years for Bill, and for the other people who have become committed to PCT, to fully realize how radically different control theory is from the rest of the behavioral sciences.  There is something about PCT that offends just about every point of view:  behaviorists, cognitive scientists, dynamic systems analysts, roboticists, cyberneticists, and even control engineers seem equally unimpressed, or baffled, or annoyed.  Well-meaning attempts to integrate control theory into the mainstream have succeeded only in confusing the issue with inaccuracies and gratuitous embellishments.  The concept of PCT is expressed as principles which contradict many fundamental assumptions:  that behavior is the end point in a chain of events, that the braincalculates necessary outputs, that the concept of purpose is unnecessary to explain behavior, that reference signals (if they exist at all) can be imposed from outside, that feedback can be given or withheld, that self-regulation is a conscious process only and has nothing to do with homeostasis, and so on, and on.

    In 40 years, Bill and his colleagues have developed a rich and comprehensive theory which encompasses and resolves many issues in the behavioral sciences.  I will never forget the astonishment, joy, and relief on Bill's face as he looked around at the people gathered at the first CSG meeting in 1985, when he really felt for the first time that control theory was not a lonely and eccentric obsession, but rather a shared enterprise that might, just might, change the behavioral sciences forever.  That hope, unfortunately, is still discouragingly far from being fulfilled, but at least it is clear that PCT no longer exclusively depends on the unique life, talents, and circumstances of a single person.