Behaviour is subjected to various controls and regulations during its demonstration. The .subject of this article is the problem of how these controls and regulations are brought into effect.
It has been stated that, for behaviour to be controlled and regulated during its demonstration, the central nervous system must be aware of behaviour itself as well as of the situations and of the changes in the incoming stimuli. Then the elements present in a feed-back system have been described and the two kinds of feed-back have been explained.