Bill Powers

An Introduction to Perceptual Control Theory— Standing at the Crossroads

Many people have some sense of what control is about, but very few understand clearly how control works and even fewer (including control engineers) understand clearly what a control systems controls: Not “output” or “action” but perception of whatever is being controlled; that which action accomplishes. When you stop to think about it, you realize that a control system knows nothing about output or actions; it “knows” only what it senses. The distinction may seem trivial, but the consequences are profound. Bill Powers puts it all in context. […]

I control therefore I am therefore I control
Introduction

Once around the loop

Elements of the control loop have been labeled slightly different by different people at different times and for different purposes, whether for a very plain explanation or for more mathematical treatment of the physical functions.  […]

Geese flying
Introduction

PCT in 11 steps

Control is a process of acting on the world we perceive to make it the way we want it to be, and to keep it that way. Examples of control: standing upright; walking; steering a car; scrambling eggs; scratching an itch; knitting socks; singing a tune. Extruding a pseudopod to absorb a nanospeck of food (all organisms control, not only human beings). The smallest organisms control by biochemical means, bigger ones by means of a nervous system. […]

Papers

The Rubber Band Demo

Dag Forssell This script and the accompanying video are designed to introduce and demonstrate the basic concept of PCT. The article Perceptual Control: Management Insight for Problem Solving, in the book: Management and Leadership: Insight […]

Books

People as Living Things. The Psychology of Perceptual Control

“I started reading your book to see whatever you have to say about systems. Then I really got fascinated by your book and read it from start to finish. Very impressive! And a feast of recognition where you say that integrating PCT into your thinking does not come overnight but takes years. Your knowledge of the psychological literature is enormous and the way you linked PCT thinking with that literature (or discussed it against the background of that literature) was very instructive to me.” —Frans X. Plooij, Director, International Research-institute on Infant Studies (IRIS), The Netherlandshen I really got fascinated by your book and read it from start to finish. Very impressive! And a feast of recognition where you say that integrating PCT into your thinking does not come overnight but takes years. Your knowledge of the psychological literature is enormous and the way you linked PCT thinking with that literature (or discussed it against the background of that literature) was very instructive to me.” —Frans X. Plooij, Director, International Research-institute on Infant Studies (IRIS), The Netherlands […]

PCT Websites

Allison Powers

Allison Powers established a Facebook page, WTPowersArchives, about Bill Powers’ personal archives at Northwestern University in Evanston, Illinois. Review and indexing of the materials is underway. Archivist: Kevin Leonard. […]