A concept that is central to all systems is feedback. Every object or organism within a system is influenced by its own actions as well as its surrounding environment. Many phenomena in nature correspond to the feedback model. One example is thermoregulation in warm-blooded animals. Cooling of the blood stimulates certain centers in the brain which "turn on" heat-producing mechanisms in the body. The body temperature is then monitored back to the center so that temperature is maintained at a constant level.

In fish schooling, the pressure sensitive lateral line and the eyes of a fish sense the proximity of its nearest neighbors. The fish's feedback mechanism performs any necessary corrections in navigation. Fish schooling is an example of emergent behavior where the real feedback mechanism is contained in the individual fish even though it appears that the fish school has a feedback mechanism.

The feedback metaphor is shown in the following diagram. Here, some input value, such as the fish's current swimming speed becomes the input value. The fish's eyes and lateral lines sense distances to nearest neighbors. This information becomes the environmental values received by the fish's internal processor. Based on the input values, the processor causes corrections to be made to the swimming speed and direction values. These values become the new swimming speed inputs in the feedback machine.

The term cybernetics derives from a Greek word which means "steersman", and which is the origin of English words such as "govern". Cybernetics is the study of feedback and derived concepts such as communication and control in living organisms, machines and organizations. Cybernetics focuses on how anything (digital, mechanical or biological) processes information, reacts to information, and changes or can be changed to better accomplish the first two tasks.

This document is a draft of work in progress. Please post your comments, thoughts, and suggestions:

Comments powered by Website Comments System ® v1.0