Geology Reference
In-Depth Information
Figure 8. Two kinds of couplings.
In our simple negative feedback, if hunger increases then food consumption increases,
which then reduces hunger. The feedback has therefore counteracted an initial increase
in hunger by triggering food consumption. Let's flow around the loop a few more times
in order to explore its longerterm behaviour. Now that hunger has been reduced, food
consumption will go down, which eventually will increase hunger, bringing us back to
the situation at the beginning. No matter how long we flow around the loop, hunger and
food consumption will oscillate around average values, and will never increase or de-
crease without limit. This loop, like all negative feedbacks, is self-regulatory.
The other basic cybernetic relationship is positive feedback
(Figure 9)
Here is a dia-
gram of a simple system of this kind.
Figure 9:A system with simple positive feedback.
