Perceptual Control Theory
A Model for Understanding the
Mechanisms and Phenomena of Control

William T. Powers, Bruce Abbott, Timothy A. Carey, David M. Goldstein, Warren Mansell, Richard S. Marken, Bruce Nevin, Richard Robertson, & Martin Taylor

Perceptual Control Theory (PCT) provides a general theory of functioning for organisms. At the conceptual core of the theory is the observation that living things control the perceived environment by means of their behavior. Consequently, the phenomenon of control takes center stage in PCT, with the epiphenomena of behavior playing an important but supporting role. The first part of the paper explains how a negative feedback control system works. This explanation includes the basic equation from which one can see what is required for control to be possible. The second part of the paper describes demonstrations that the reader can download from the Internet and run, so as to learn the basics of control by experiencing and verifying the phenomenon directly. The third part of the paper shows the application of PCT to psychological research, learning and development, conflict, and psychotherapy. This summary of the current state of the field celebrates the 50th Anniversary of the first major publication in PCT (Powers, Clark & MacFarland, 1960).

Key words: Nature of control, Control theory, Control of perception, Negative Feedback, Computer Models, Conflict and control