Understanding PCT

Understanding Purposeful Behavior

Perceptual Control Theory (PCT) gives an intuitively satisfying explanation for purposeful human behavior, where purposeful behavior is also known as control.

Hierarchical PCT (HPCT) outlines a hierarchical arrangement of multiple control systems as a testable explanation that allows for the complexity of our experience.

PCT focuses on how we look at and experience things, and the way these perceptions are compared with experiences we want. PCT explains how thoughts become actions and feelings and why stimuli appear to cause responses.

PCT improves our understanding of human interpersonal behavior, including conflict, cooperation and leadership in families , education, business and society.

Look Under the Hood or Take a Test Ride?

To illustrate, think of people as cars directed by voice commands. The cars sometimes respond the way you want them to, sometimes not. No-one has been able to peek under the hood and figure out what makes them tick, but "theories" abound, are widely accepted and have become engrained in our language. PCT describes a physical mechanism you can test and use to visualize the internal structure at work in purposeful behavior. This means that PCT lays the foundation for a new science which explains -- in terms of physical processes, not word pictures -- how living systems function at all times. To look under the hood, proceed to other books and programs in this guide.

If you would rather begin with a test ride, to get a feel for a PCT-inspired approach to understanding human relationships, I suggest you read Freedom From Stress by Edward E. Ford. Watch as Ed takes you on a test drive using PCT to show how people cause their own problems. This easy-to-read counseling story deals with relationships at work, with spouses and with children.

What PCT Is

(See also PCT in a nutshell and The Nature of HPCT).

Let me relate PCT and HPCT to "reverse-engineering."

Suppose you manufacture electronic products and your competitor has just introduced a marvelous product of unknown design. It is difficult to figure out how the new device was made, because it is made up of millions of components. To "reverse-engineer" it you:

1) describe what the device does (how it behaves) in some detail,

and

2) suggest physical explanations.

Based on these, you design and test a circuit or mechanism which performs just like the unknown product in all circumstances.

Now you can claim that you understand at least one way the unknown device might actually work -- and you are probably certain of many ways that cannot work.

PCT proposes an organization or physical model of the nervous system. We can test the PCT model by letting it behave by itself, and compare the result with the behavior of the real thing -- people.

Since it is ourselves we reverse-engineer, we naturally require that the explanation and model we come up with feels right; that it intuitively makes sense to us when we are told how we work.

Simulations and personal experience indicate that PCT is a valid model. PCT appears to be the first approach to explaining human behavior that holds up to critical scientific scrutiny and is worth refining.

PCT proposes a physical structure or architecture of the human nervous system, observable both at the macro level of major action and at the micro level of individual muscle fibers. This comprehensive proposal is grounded in the physical sciences and is detailed and universal enough to allow anyone interested to carry out the basic experiments that illustrate how purpose works, resulting in the human behavior we observe in ourselves and people all around us, all the time.

Applying PCT

To drive a car, it is important to know how the controls work, but it is not necessary to understand how the controls are designed in detail -- you can leave that to the engineers.

To apply PCT in daily life, it is important to understand the basic concept -- why the controls work the way they do -- but it is not necessary to understand all the technical details -- you can leave that to the PCT researchers.

When you understand the basic concept of PCT, you will observe yourself and others and at the same time visualize the internal mechanism in action. Your understanding of the internal mechanism will give you greater ability to enjoy your ride through life and to show others how to enjoy theirs, too.

Where PCT Comes From

PCT is the creation of one man's background, curiosity and determination. William T. (Bill) Powers learned about control systems and analog computers -- key for the development of PCT. He studied physics and other applied physical sciences necessary to reverse-engineer the human nervous system.

Bill's seminal book Behavior: The Control of Perception, published in 1973, is still in print and is must reading for the serious PCT student. When you order it, you will no longer get a jacket, so I have reproduced the original book jacket (now a separate article). Note comments by Russell L. Ackoff, Carl R. Rogers, and Thomas S. Kuhn among others. A prolific, lucid writer, Bill has also collaborated in the creation of a college text. Living Control Systems I and II are collections of his papers.

Seeing how control works is better than reading about it. For demonstration programs simulating an analog control system on a digital PC with tutorials, simulations, explanations and discussions, see PCT demos and PCT texts.

Welcome to PCT!

Dag C. Forssell
Valencia, California
Dec, 1996