Cybernetics

Cybernetics, interdisciplinary science dealing with communication and control systems in living organisms, machines, and organizations. The term, derived from the Greek word kybernētēs (“steersman” or “governor”), was first applied in 1948 to the theory of control mechanisms by the mathematician Norbert Wiener.

Cybernetics developed as the investigation of the techniques by which information is transformed into desired performance. The science arose out of problems that were encountered during World War II in the development of so-called electronic brains and automatic-control mechanisms for military apparatuses such as bombsights.

Systems of communication and control in living organisms and those in machines are considered analogous in cybernetics. To achieve desired performance from human organs or from mechanical devices, information concerning the actual results of intended action must be made available as a guide for future action. In the human body, the brain and nervous system function to coordinate the information, which is then used to determine a future course of action; control mechanisms for self-correction in machines serve a similar purpose. The principle is known as feedback, which is the fundamental concept of automation.

According to information theory, one of the basic tenets of cybernetics is that information is statistical in nature and is measured in accordance with the laws of probability. In this sense, information is regarded as a measure of the freedom of choice involved in selection. As the freedom of choice increases, the probability that any particular message will be chosen decreases. The measure of probability is known as entropy. According to the second law of thermodynamics, in natural processes the tendency is towards a state of disorganization, or chaos, occurring without assistance or control. Thus, according to the principles of cybernetics, order (lowering of entropy) is least probable and chaos (increased entropy) is most probable. Purposive behaviour in humans or in machines requires control mechanisms that maintain order by counteracting the natural tendency towards disorganization.

Cybernetics has also been applied to the study of psychology, artificial intelligence, servomechanisms, economics, neurophysiology, systems engineering, and the study of social systems. The term cybernetics is no longer much used to describe a separate field of study, and most of the research activity in the field now focuses on the study and design of artificial neural networks.