When Excessive, Feedback Can Be Upsetting
For many years, I drove around with a bumper sticker on my car that read: Stop complementary schismogenesis!
It probably did more to stop traffic than halt the escalating arguments to which it refers, but I liked the sentiment anyway. I stole the phrase from linguist Deborah Tannen, who uses the term to describe those little linguistic misfires that can so easily spiral out of control: Genesis, for beginning. Schismo, for rift. Complementary for actions and reactions that feed on each other. A relativity minor misunderstanding between men and women (or different nations) explodes into divorce (or war).
It is a typical example of what is commonly called a feedback loop: One thing pushes on another, which in turn pushes back on the first, which in turn causes the first to push back again, and so on and so forth, often with ever-increasing force.
Examples of such phenomena pervade the physical world as well. Consider stars. A star is born when a huge cloud of gas collapses under its own weight and the center heats up enough to ignite a nuclear fire. The fusion of hydrogen into helium releases enormous amounts of energy, which pushes back on gravity, halting the collapse.
This state of near equilibrium can last for a long time (our sun has been doing this for billions of years) but not forever. Eventually, the star runs out of hydrogen to burn. The core collapses, heating up this time enough to fuse helium into carbon and oxygen--a much more violent reaction. The star expands suddenly in what is known as a “helium flash.”
Now the argument between the inward pull of gravity and the outward push of nuclear energy gets truly heated. And things speed up. If the star is big enough, the core collapses again, this time burning carbon and oxygen into heavier elements still. And so it goes, hotter and hotter, faster and faster, schismogenesis run amok.
By the time the star collapses entirely and explodes as a supernova, the whole process takes place in a matter of seconds.
The key to a feedback system is that whatever happens responds to what came before, over and over again.
A predator gets so good at hunting down its prey that the prey population plummets. The predator goes hungry. The prey rebounds.
Or not.
Feedback systems are tricky. For example, overfishing along the Pacific Northwest left killer whales with not enough to eat, so they started going after sea otters. Sea otters eat sea urchins. With fewer otters to gobble them up, the urchin population exploded. Urchins eat kelp, and so in turn gobbled up the kelp forests. Fish depend on kelp for both food and shelter, so fish lose out at both ends of the chain.
The complexity of feedback systems explains why climate, for example, is so difficult to understand. Global warming means the muggy air can hold more water vapor, which absorbs heat, warming the atmosphere even more. But more water vapor means more clouds, which could reflect the light of the sun back into space, cooling things down.
Alas, as feedback cycles speed up, things may happen too fast for effective intervention. Like stars, ecosystems and climate systems can rapidly collapse.
Not that all feedback leads to bad ends. Quite the contrary. The collapse and explosion of stars seeds the universe with the elements that go into making, among other things, us.
Thermostats and flywheels are feedback systems. So is your body. If it gets too hot, it sweats, which cools you down. If it gets too cold, it shivers, which heats you up. If it runs out of fuel, it gets hungry, and you eat. If you get too full, you stop (chocolate, of course, doesn’t count). Even the simple act of standing up requires constant feedback to keep you from falling over.
Science is a self-correcting system because it thrives on feedback from peers. Democracy is a solid form of government because of feedback from elections, polls and a strong, free press.
We even invent social feedback systems to smooth our daily lives--like that little wave drivers give to other drivers kind enough to let them into a crowded lane, which encourages similar kindness down the line. Or so I like to think.
Feedback systems are destructive when they go too far, too fast. Like exit polling that influences elections, autopilots that overcorrect, politicians who lurch from one policy to another. Or nations that respond to attacks with ever-increasing counterattacks.
Wouldn’t it be nice if someone could invent a fuse for complementary schismogenesis that temporarily shuts down runaway feedback the way electrical fuses stop overheated circuits from melting down?
It would do a lot more good than my bumper sticker.
