Negative feedback arises out of balances between forces and factors that mutually influence each other. To illustrate several of its important characteristics, we can regard a car and its driver as a unified, complex, homeostatic or "goal-seeking" system--a cyborg, or "cybernetic organism," in that it seeks to keep the car moving on track. The driver does not steer by holding the wheel in a fixed position but keeps turning the wheel slightly to the left and right, seeking the wheel positions that will bring the naturally meandering car back on track. Disturbance, or departure from equilibrium, is every bit as important as negative feedback: Systems cannot correct themselves if they do not stray.
Oscillation is a common and necessary behavior of many systems. If the car skids, the driver automatically responds by quickly steering in the opposite direction. Such abrupt negative feedback, however, usually over-corrects, causing the car to move toward the other side of the road. A negative feedback, if it is as large as the disturbance that triggered it, may become an impressed change in the direction opposite to that of the original disturbance. The car and driver recovers from the skid by weaving from side to side, swerving a little less each time. In other words, each feedback is less than the last departure from the goal, so the oscillations "damp out." Negative feedback takes time and such a time lag is an essential feature of many natural systems. This may set the system to oscillating above and below the equilibrium level.