William T. Powers'
Perceptual Control Theory

Perceptual Control Theory, or PCT, asserts that the function of behavior is the control of perception. Perceptions are controlled when they are brought to and kept near dynamically specified internal reference levels despite the effects of other variables that tend to disturb those perceptions. Control systems behave purposefully, setting goals, taking action to bring about those goal states, and taking further action to maintain those states against opposing forces. On this site you can learn about perceptual control theory and access links to related web sites.

About Perceptual Control Theory

• Synopsis of PCT
  A brief description of perceptual control theory (PCT) and hierarchical perceptual control theory (HPCT).

CSG Robotics Lab Projects

The Control Systems Group has provided seed money to begin developing robotic agents that will serve as testbeds for architectures based on Perceptual Control Theory (PCT). Our initial project is a hexapod robot to provide an embodied, situatated version of the " Archy" bug computer simulation by Richard Kennaway. Other projects may follow (e.g., a robotic "little-man" demo similar to Rodney Brooks' "Cog").

• PCT Hexapod Robot Project

Examples of Control in the Operant Literature

• Stein and Ray (1959)
  Two rats were given control over the intensity of reinforcing brain-stimulation.
• Weiss and Laties (1961)
  These rats worked in a cold environment for brief bursts of heat from an overhead heat lamp, and succeeded in maintaining a nearly constant sub-dermal skin temperature.

Related Reading

• My notes on W. Ross Ashby's An Introduction to Cybernetics

Off-Site Links

• Control Systems Group (CSG) website
  CSG is a non-profit organization dedicated to the promotion of perceptual control theory research and application.
• CSGnet Archive
  CSGnet is the official electronic discussion list for CSG. At this link you can access the archived posts to CSGnet from one year in the past up to the present.
• Journal on Perceptual Control Theory
  JPCT is an electronic outlet for research on perceptual control. [Note: It has been inactive since the posting of its first edition in Spring 1999.]