Suppose that you have 100 people working for you and you decide never to hire anyone again. Your average worker hangs around for 10 years. What will happen to your workforce? This is an example of a first order negative feedback loop.
The number of workers will decrease, very quickly at first and then more slowly. This is the opposite of exponential growth where changes was slow at first and then quick and there is a similar constancy in exponential decay. If it takes, as it does here, about seven years for half the workers to leave, it will take another seven for half of those that remain to leave. It is interesting to experiment and see the relationship between average tenancy and the time it takes half the workers to leave.
The important thing about exponential decay is that if you move the goal away from zero, you get the same behavior. Suppose you have a house at 10 degrees and you put it into a 40 degree neighborhood, what happens to the house temperature?
