Negative Feedback Loops

# 8. The strength of negative feedback loops, relative to the impacts they are trying to correct against Now we're beginning to move from the physical part of the system to the information and control parts, where more leverage can be found.

Negative Feedback Loops are ubiquitous in systems. Nature evolves them and humans invent them as controls to keep important system states within safe bounds. A thermostat loop is the classic example. Its purpose is to keep the system state called "room temperature" fairly constant at a desired level. Any Negative Feedback loop needs a Goal (the thermostat setting), a Monitoring and Signaling device to detect excursions from the goal (the thermostat), and a Response Mechanism (the furnace and/or air conditioner, fans, heat pipes, fuel, etc.).

A complex system usually has numerous negative feedback loops that it can bring into play, so it can Self-Correct under different conditions and impacts. Some of those loops may be inactive much of the time. like the emergency cooling system in a nuclear power plant, or your ability to sweat or shiver to maintain your body temperature. They may not be very visible. But their presence is **critical to the long-term welfare of the system**.

One of the **big mistakes** we make is to strip away these "emergency" response mechanisms because they aren't used often and they appear to be costly. In the short term, we see no effect from doing this. In the long term, we drastically narrow the range of conditions over which the system can survive. One of the most heartbreaking ways we do this is in encroaching on the habitats of endangered species. Another is in **encroaching on our own time for rest, recreation, socialization, and meditation**.

The "strength" of a negative loop--its **ability to keep its appointed stock at or near its goal** depends on the combination of all its parameters and links--the accuracy and rapidity of monitoring, the quickness and power of response, the directness and size of corrective flows. Sometimes there are leverage points here.

Take Markets, for example, the negative feedback systems that are all but worshipped by economists--and they can indeed be marvels of self-correction, as prices vary to moderate supply and demand and keep them in balance. The more the price--the central piece of information signaling both producers and consumers--is kept clear, unambiguous, timely, and truthful, the more smoothly markets will operate. **Prices that reflect full costs** will tell consumers how much they can actually afford and will reward efficient producers.

Companies and governments are **fatally attracted** to the price leverage point, of course, all of them determinedly **pushing it in the wrong direction** with subsidies, fixes, externalities, taxes, and other forms of confusion.

These folks are trying to weaken the feedback power of market signals by **twisting information in their favor**. The real leverage here is to keep them from doing it. Hence the necessity of antitrust laws, truth-in-advertising laws, attempts to internalize costs (such as pollution taxes), the removal of perverse subsidies, and other ways to level market playing fields.

None of which get far these days, because of the weakening of another set of negative feedback loops: those of democracy. This great system was **invented to put self-correcting feedback between the people and their government**. The people, informed about what their elected representatives do, respond by voting those representatives in or out of office. The process **depends upon the free, full, unbiased flow of information back and forth between electorate and leaders**. Billions of dollars are spent by leaders to limit and bias that flow. Give the people who want to distort market price signals the power to pay off those leaders, get the channels of communication to be self-interested corporate partners themselves, and **none of the necessary negative feedbacks work well**. Market and democracy help each other erode.

The strength of a negative feedback loop is important relative to the impact it is designed to correct. If the impact increases in strength, the feedbacks have to be strengthened too. A thermostat system may work fine on a cold winter day, but open all the windows and its corrective power will fail. Democracy worked better before the advent of the brainwashing power of centralized mass communications. Traditional controls on fishing were sufficient until radar spotting and drift nets and other technologies made it possible for a few actors to wipe out the fish. **The power of big industry calls for the power of big government to hold it in check; a global economy makes necessary a global government.**

Here are some examples of **strengthening negative feedback controls** to improve a system's self-correcting abilities: • preventive medicine, exercise, and good nutrition to bolster the body's ability to fight disease • integrated pest management to encourage natural predators of crop pests; • the Freedom of Information Act to reduce government secrecy: • monitoring systems to report on environmental damage, • protection of whistleblowers: • impact fees. pollution taxes, and perfor- mance bonds to recapture the externalized public costs of private benefits