SATM 4.7.2 Negative Feedback

Exceedingly complex probabilistic systems have to be controlled through self-regulation. The understanding of self-regulation that cybernetics can provide is important to managers for two reasons. First, it is the existence of mechanisms bring about self-regulation that gives a degree of stability to the environment of organizations. Second, if managers understand the nature of self-regulation they may be able to induce it in the organizations they manage.

The work of winer (1948, Cybernetics, Wiley, NY.) has established that the way to ensure self-regulation is through the negative feedback mechanism. It operates by the continuous feedback of information about the output of the system. This output is then compared with predetermined goal, and if the system is not achieving its goal, then the margin of error (the negative feedback) becomes the basis for adjustments to the system designed to bring it closer to realizing the goal.

A feedback system to work properly, four elements are required:

• A desired goal, which is conveyed to the comparator from outside the system
• A sensor (a means of sensing the current state of the system)
• A comparator, which compares the current state and the desired outcome
• An activator (a decision-making element that responds to any discrepancies discovered by the comparator in such a way as to bring the system back toward its goal)

Homeostasis in the body is achieved by negative feedback, so that the body is able to maintain stability in spite of extensive shifts in outside circumstances.

In designing feedback control systems, it is important that managers ensure that there is rapid and continuous comparison of actual performance against the desired goal, and similarly rapid and continuous taking of corrective action if necessary. If there are delays of lags in the system, attempted adjustments may only add to instability.

(Jackson, 2000, Systems Approached to Management, Klumer Academic / Plenum Publishers, NY. p71~71)