Many systems — animals, machines, even cities — self-regulate by using feedback about their own results, the same way a thermostat shuts off heat once it is warm enough.

Systems self-regulate by using feedback from the results of their own actions.

Wiener called the study of feedback loops cybernetics: a system measures the effect of its own action and adjusts its behavior based on that effect. A thermostat reads the temperature, compares it to the target, then turns heat on or off. Your body does the same when it shivers.

Why it matters This idea of continuous feedback underlies modern robots and the autopilot systems in aircraft.