PCT Home
Perceptual Control and Human Data Fusion
 

1. Introduction

2. Modes of Perception

3. Perceptual Control Introduction

4. Perceptual Control and imagination

5. Hierarchic Perceptual Control

6. Multiple data sources

7. Learning and Conflict

8. The Bomb in the Hierarchy

9. Degress of Freedom in the individual

10. Degrees of Freedom in the organization

11 Modes of Perception (Reprise)

12. Side Effects and Military intelligence

13. Communication

Learning

  • Reorganization: Changing the connections in the hierarchy. Can change the nature of what is being perceived. Can lead to dramatic and possibly dangerous changes if it affects a perception under active control.
  • Modification: Continuous, smooth changes in weights of connections either of perceptual functions (what should I be perceiving) or of action–reference connections (how should I be controlling).

The term "Reorganization" is sometimes used in Perceptual Control Theory for all types of learning, whether random or directed. Modification is often done by gradient search—incremental improvement.

The control hierarchy does not appear full-blown and functioning from nowhere. It must be developed, and must adapt to changing situations. In PCT, the generic term for alterations in the hierarchy is "reorganization," though this term might better be limited to alterations in the organization of the hierarchy such as the structure of the interconnections among ECSs.

Learning may be through gradual modification of the parameters in the Perceptual Input Functions or the reference signal collection functions. Since the interconnections of the PIFs is exactly that of the nodes in a multilayer perceptron (MLP), and a PIF may have the structure of a MLP node, any learning algorithm appropriate to that kind of a neural network can be applied to the ECS hierarchy.

Reorganization often applies to changes in the sign of outputs, to ensure negative feedback, or to the generation of new ECSs to control some new CEV. It can, however, refer to changes in any aspect of the connectivity of the multitudinous ECSs in a hierarchy. It can have drastic effects if it occurs during active perceptual control.

In "conventional" Perceptual Control Theory, the likelihood of reorganization on the neighbourhood of a particular ECS depends on how well that ECS is controlling. The better it controls, the lower the likelihood of reorganization in its neighbourhood.

Possible conflict in a portion of a network

ECSs normally control their perceptions by sending their outputs as reference signals to lower ECSs, which return perceptual signals that should conform to the references as inputs to the higher PIFs. It is normal that several different higher ECSs may use a common lower one as part of their control loop. In the figure, the ECS on the shaded background is used by both higher ECSs, and each of the higher ones also uses another lower ECS as part of its support structure. Usually, the sharing causes no difficulty, because although neither of the higher ECSs will necessarily get the percept it wants from the shared one, the difference can normally be made up through the independent supporting ECS. But if the action of the independent one is blocked, then the behaviour of the shared one becomes more important, and the fact that it is shared may lead to conflict, a situation in which two ECSs cannot simultaneously bring their perceptual signals to the corresponding reference values.

This kind of conflict can lead to Reorganization, in which either or both of the higher-level ECSs reduce their dependence on the conflicted one.