What is Control? A historical Introduction Dr Warren Mansell

What is Control? A Historical Introduction

• Dr Warren Mansell

• 3rd Year Module

• University of Manchester

William James (1842-1910)

• American psychologist and philosopher

• Author of “The Principles of Psychology” (1890) – key publication

• Regarded psychology as the study of purpose

James (1890)

• “Romeo wants Juliet as the filings want the magnet; and if no obstacles intervene he moves towards her by as straight a line as they. But Romeo and Juliet, if a wall be built between them, do not remain idiotically pressing their faces against its opposite sides like the magnet and the filings with the card. Romeo soon finds a circuitous way, by scaling the wall or otherwise, of touching Juliet's lips directly. With the filings the path is fixed; whether it reaches the end depends on accidents. With the lover it is the end which is fixed, the path may be modified indefinitely.”

James (1890)

• “Suppose a living frog in the position in which we placed our bubbles of air, namely, at the bottom of a jar of water. The want of breath will soon make him also long to rejoin the mother-atmosphere, and he will take the shortest path to his end by swimming straight upwards. But if a jar full of water be inverted over him, he will not, like the bubbles, perpetually press his nose against its unyielding roof, but will restlessly explore the neighborhood until by re-descending again he has discovered a path around its brim to the goal of his desires. Again the fixed end, the varying means!”

James (1890)

• “The Pursuance of future ends and the choice of means for their attainment, are thus the mark and criterion of the presence of mentality in a phenomenon. We all use this test to discriminate between an intelligent and a mechanical performance. We impute no mentality to sticks and stones, because they never seem to move for the sake of anything, but always when pushed, and then indifferently and with no sign of choice. So we unhesitatingly call them senseless.”

Returning to History

• How does purpose work?

• What does an human, animal or machine do so that it reaches an end through variable means?

The Clepsydra – Water Clock

• Ktesibios c.200BC

• used a cone-shaped float to monitor the level of the water in its reservoir

• adjust the rate of flow of the water to maintain constant level of water in reservoir (‘goal’)

• neither overflowed nor was allowed to run dry.

• first artificial truly automatic self-regulatory device that required no outside intervention between the feedback and the controls of the mechanism

Homeostasis

Examples of homeostasis

• Temperatrue - thermoregulation

• Glucose levels – glucoregulation

• Hormone levels

• Salt and ion levels - osmoregulation

Control Engineering

Control System Examples

• Thermostat

• Cruise Control

• Automatic Pilot

• Telescope Guidance

• Guided Missiles

• Amplifiers

Cybernetics

• Greek word ‘cyber’, meaning steersman on a boat

• “the study of control and communication in the animal and the machine” - Weiner (1948)

• How do systems adjust their outputs to reach a fixed, internal goal?

• Negative feedback systems

Where did cybernetics go?

• Information theory – transmission of information over a noisy channel

• Cognitive psychology

• an input–transformation–output model of the mind
• Sequential, environmentally driven, digital

• 1966 Cybermen in Dr Who; 1970s computers; 1980s William Gibson – not the same meaning!

Perceptual Control Theory (PCT)

• Maintains cybernetic principles of feedback control

• Developed during the 1950s by a physicist/engineer – William T. Powers

• First published Powers, Clark & McFarland (1960)

• Formalised Powers (1973)

• Latest Edition 2005

• New book, with computer simulations, to be publisehd Spring 2007

Self-Regulation Theory

• Study of the control of behaviour and affect

• Behaviour Self-Regulation - Carver & Scheier (1982; 1998)

• Loss of control – Baumeister et al.

• Affect Regulation – Gross

• Not the same as Perceptual Control Theory – explores the control of perception

Summary

• Historical development of self-regulatory approaches

• Dilution of central principles over time

• Arguably, PCT adheres most closely to the original principles

• Further details to follow!