Georg Ivanovas From Autism to Humanism - systems theory in medicine

4. Systemic Basics

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4.4 Cybernetic Cycles

A cybernetic cycle is nothing else than a refined version of a recursive process creating a stable state. The foundations of cybernetics through Norbert Wiener and his important book Cybernetics – or Control and Communication in the Animal and the Machine (1948) is well documented.

The classic cybernetic cycle is depicted in many different ways. Here I use a basic diagram how it could be found in a central heating. The set point is the aimed temperature in the room: Then there is a sensor for the actual temperature and a controller to compare the actual temperature with the set point. If the room is cooler than it should be the controller activates the heater (effector) which warms up the room (state of affaires). If it is warm enough the controller switches the heater off. Cold air coming from outside and losses through walls and windows are the sources of disturbance.


Likewise is the thermoregulation in the honey bees’ nests. The temperature in the nest ranges between 32 and 36 degrees. If it is getting warmer the bees ventilate with their wings until the set point is reached again. In genetically uniform colonies the bees tend to start with ventilation about the same time producing more temperature fluctuations, whereas temperature in genetically diverse colonies is more stable (Jones et al 2004), something that can be seen as an advantage of biodiversity.

Most, if not all, physiological and biochemical process are integrated in several cybernetic cycles, as seen here with the regulation of the thyroid gland.

The cybernetic model soon attracted the attention of the Mental Research Institute in Palo Alto. The researchers found that also behaviour can be described in this terms (Haley 1963).

An example for a cybernetic cycle in the human behaviour is the noise at meals. Each meal has its own set point.(in the family circle, with friends, at marriages, at obsequies). If it is too silent someone will take the initiative to talk and if it is too loud, someone will be active to calm everything down (verbally or nonverbally). At first, it does not matter who starts and what is talked about. Important is that the set point is attained. Of course, these set points are different in different cultures. The film My big fat Greek wedding shows the tremendous difference between an extended Greek tribal-family and an American WASP nuclear family.

This rather simple example reveals already a lot of important characteristics of a ‘complex adaptive system’ (chap. 2.8) which are likewise found in physiological and biochemical processes. For example, these systems are nonlinear, unpredictable, have a distributed control, show equifinality and goal-orientation. In terms of information theory it is also interesting that a cybernetic system in equilibrium doesn’t seem to be active. Only in the case of an imbalance signals are sent, at least in this simple model.


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