Perceptual control theory

Perceptual control theory (PCT) is a psychological theory of animal and Human behavior originated by unaffiliated scientist William T. Powers. In contrast with other theories of psychology and behavior, which assume that behavior is a function of perception — that perceptual inputs determine or cause behavior — PCT postulates that an organism's behavior is a means of controlling its perceptions. In contrast with engineering control theory, the reference variable for each negative feedback control loop in a control hierarchy is set from within the system (the organism), rather than by an external agent changing the setpoint of the controller. PCT also applies to nonliving autonomic systems.

Introduction

Perceptual control theory is a testable, comprehensive model of the psychological processes occurring within living beings, including humans, which centers on the concept that animals are goal-driven, purposeful entities rather than automata repeating conditioned responses to external stimuli. Behavior is the means by which the animal controls its perceptions.

Familiar examples of a simple negative feedback control system include a thermostat and a cruise control system. Cruise control has a sensor which "perceives" the speed of the automobile (the speedometer) and an internal, preset 'goal' (the set speed). The sensed input is continuously compared against the goal by a comparator function, which subtracts the sensed input value from the goal value. T The difference (the error signal) determines the throttle setting (the accelerator), so that the engine output is continuously varied to counter variations in the speed of the car. If the speed of the car is lower than the goal, for example when climbing a hill, the engine output increases and then gradually declines as the speed approaches the goal; if the speed exceeds the goal, e.g. when going down a hill, the engine is throttled back so as to act as a brake, and then as the car slows toward the set speed the engine output is gradually increased. The result is that the cruise control system maintains a speed close to the goal as the car goes up and down hills, and as other disturbances such as wind affect the car's speed.

The same principles of negative feedback control apply to living control systems. Animals and people do not control their behavior, rather, their behavior is their means for controlling their perceptions. This means that perceptions and goals drive the system or organism, not preset behavior patterns as implied by early theories of Behaviorist Psychology. Perceptions are constructed in a hierarchy. For example, visual perception of an edge is constructed from differences in light intensity, perception of the configuration of an object is constructed from edges, and so on, up to the most abstract philosophical and theoretical constructs. Any perception may be brought under control, to maintain it in preferred states. In a hierarchy of control systems, higher levels adjust the goals of lower levels as their means of approaching their own preset goals. Of course a control system has output behaviors that it uses to attempt to control its input perceptions, but these are theorized to be selected for and controlled by a parallel system within the hierarchy, the reorganization system. This changes behavioral outputs of the control systems when the outputs are no longer reducing the 'error' being perceived by the control systems, and it seemingly does this randomly to test and select as many options as possible until a new behavior produces a reducing error signal. Reorganization may occur at any level when control at that level causes error at levels above them. This is the mechanism that is involved in learning. It closely parallels within the individual the processes of evolution by natural selection in the species.

In a hierarchy of interacting control systems conflicting outputs and perceptions are possible. When two systems are controlling the same variable with different goals, they are in conflict. When two opposing systems are locked into a static pattern, it is a source of psychological distress. Higher level control systems may seek perceptions that don't produce the conflict. Normally, this takes place without notice. If the conflict persists, the "problem solving" by higher systems comes to awareness, and if it fails the reorganisation system may find new systems that bypass the conflict or may construct new reference signals (goals) that are not in conflict. New perceptual constructs and new means of controlling the perceptions involved may also result from reorganization. The reorganization process is to vary things until something works, at which point we say that the organism has learned.

Perceptual control theory identifies a hierarchy of at least 11 levels of control systems in the human mind and neural architecture. These are: intensity, sensation, configuration, transition, event, relationship, category, sequence, program, principle, and system concept. Diverse perceptual signals at a lower level (e.g. visual perceptions of intensities) are combined in an input function to construct a single perception at the higher level (e.g. visual perception of an edge). Partial input may suffice to construct the higher-level perception (e.g. partial occlusion of the edge by a shadow). The perceptions that are constructed and controlled at the lower levels are passed along as the perceptual inputs at the higher levels. The higher levels in turn control what the lower levels "want" to perceive, that is, they preset the reference levels (goals) of the lower levels.

This setting of goals or expectations for perceptions that are constructed from diverse inputs at lower levels is a plausible cause of many common optical illusions and cognitive flaws in which expectations influence what is perceived in a situation when sensory input is only partial. A PCT interpretation of recent evidence for "grandmother neurons" storing individual memories in the brain's cortex suggests that a partial stimulation of a memory should produce a 'goal' or expectation of a full perception. An example is when we partially see a face and momentarily perceive it as a familiar face until enough sensory information is received to falsify that expectation and disclose it as a stranger.

History

See interviews with William T. Powers under "External links" below.

Research and applications

Selected readings

• Marken, R.S. (2002). More Mind Readings: Methods and Models in the Study of Purpose. St. Louis: newview. ISBN 0-944337-43-0
• Powers, W. T. (1988). Making sense of behavior: The meaning of control. New Canan, CT: Benchmark Publications. ISBN 0964712156
• Runkel, Philip J. (2003). People as living things. Hayward, CA: Living Control Systems Publishing. ISBN 0-9740155-0-4

References

• Carey, T.A. (2005). The method of levels. Hayward, CA: Living Control Systems Publishing.
• Goldstein, D.M. (1989a). Q methodology and control systems theory. Operant Subjectivity, 13, 8-14.
• Goldstein, D.M. (1989b). Control theory applied to stress management. In WA. Hershberger (Ed.), Volitional action (pp. 481-491). Amsterdam: Elsevier.
• Goldstein, D.M. (1990). Clinical applications of control theory. In R.S. Marken (Ed.), Purposeful behavior: the control theory approach (Theme). American Behavioral Scientist, 34, 2.
• Goldstein, D.M. (1991). Q methodology and control theory: II. general considerations. Operant Subjectivity, 14, 61-74.
• Goldstein, D. M. & Goldstein, S. E. (in press). Q Methodology Study of a Peron in Individual Therapy. Clinical Case Studies.
• Mahrer, A.R. (1989) . The integration of psychotherapies. New York: Human Sciences Press.
• Marken, R.S. (Ed.). (1990). Purposeful behavior: the control theory approach (Theme) . American Behavioral Scientist, 34, 2.
• Powers, W.T. (1973). Behavior: The control of perception. Chicago: Aldine.
• Powers, W.T. (1989). Living control systems: Selected papers of William T. Powers. Gravel Switch, KY: Control Systems Group.
• Robertson, R.J. & Powers, W.T. (1990). Introduction to modern psychology: the control-theory view. Gravel Switch, KY: Control Systems Group.
• Robertson, R. J., Goldstein, D.M., Mermel, M., & Musgrave, M. (1999). Testing the self as a control system: Theoretical and methodological issues. Int. J. Human-Computer Studies, 50, 571-580.

Sociology

• McClelland, Kent. (1994). Perceptual Control and Social Power. Sociological Perspectives, 37, 461-496.

• McClelland, Kent. (2004). The Collective Control of Perceptions: Constructing Order from Conflict. International Journal of Human-Computer Studies, 60, 65-99.

• McClelland, Kent and Thomas J. Fararo, eds. (2006). Purpose, Meaning, and Action: Control Systems Theories in Sociology. New York: Palgrave Macmillan.

General references

• Cziko, Gary. (1995). Without miracles: Universal selection theory and the second Darwinian revolution. Cambridge, MA: MIT Press (A Bradford Book). ISBN 0-262-53147-X (Online)
• Cziko, Gary. (2000). The things we do: Using the lessons of Bernard and Darwin to understand the what, how, and why of our behavior. Cambridge, MA: MIT Press (A Bradford Book). ISBN 0-262-03277-5 (Online)
• Marken, Richard S. (1992) Mind readings: Experimental studies of purpose. Benchmark Publications: New Canaan, CT.
• Marken, Richard S. (2002) More mind readings: Methods and models in the study of purpose. Chapel Hill, NC: New View.
• Powers, William T. (1973). Behavior: The control of perception. Chicago: Aldine de Gruyter. ISBN 0-202-25113-6
• Powers, William T. (1998). Making sense of behavior: The meaning of control. New Canaan, CT: Benchmark Publications. ISBN 0964712156

• Runkel, Philip J. (2003). People as living things. Hayward, CA: Living Control Systems Publishing. ISBN 0-9740155-0-4

External links

• Articles
  • Web articles on PCT
  • PCT for the Beginner by William T. Powers (2007)
  • The Dispute Over Control theory by William T. Powers (1993)
  • Demonstrations of perceptual control by Gary Cziko (2006)
• Audio
  • Interview with William T. Powers on origin and history of PCT (Part One - 20060722 (58.7M)
  • Interview with William T. Powers on origin and history of PCT (Part Two - 20070728 (57.7M)
• Websites
  • The Control Systems Group
  • Living Control Systems Publishing - resources and books about PCT
  • William T. Powers' website
  • Mind Readings - Rick Marken's website on PCT