Positive Feedback Loops: The Cause of Everything Interesting

by Jasper Gilley

One of the key things about human civilization is that technological progress isn’t linear. Progress is made in intense, sudden bursts that are hard to foresee and harder to predict the results of. If one were to graph the progress of a particular industry as it underwent one of these bursts, it would be exponential, like this:

Generally, exponential progress leads to interesting things in history. This curve (sometimes known as a J-curve) can be found during the Industrial Revolution, the late 20th century IT Revolution, and the Agricultural Revolution (the first one, in 10,000 BC).

The thing is, one’s metric of progress doesn’t matter. These three revolutions revolutionized totally different sectors, yet they all exhibit the same curve. In the Industrial Revolution, one might have measured progress by the inverse cost of clothing. In the IT Revolution, one might measure progress by the number of transistors on a given area of microchip. In the Agricultural Revolution, one might have measured progress by the total human population. All three yield the same curve.

This is kind of suspicious. Three major revolutions in three totally different times with totally different effects yielding the same J curve is nice. History isn’t supposed to be nice. Usually, there is a reason that nice things are nice.

To find the reason, we have to look at why humans exist. There is a surprising lack of literature on this subject. The Wikipedia page for Human will tell you plenty about how humans got to be the way they are, but very little about why. Though it’s very much still an open question, we know that a large part of its answer lies in natural selection. Early humans had somewhat of an advantage over others if they were smarter than average: the smart ones could find more food, design better weapons, and more connivingly manipulate the social order to their benefit. As a result, they died less and reproduced more, which is all natural selection really cares about.

As time went on, early humans as a species kept getting smarter and smarter, and as their intelligences further diverged from those of other animals, intelligence became ever more of a hot commodity. The end result (or rather, the beginning result, from our perspective) was what the distant descendants of these proto-humans know as a positive feedback loop:

Effectively, rising intelligence caused intelligence to be more desired (top arrow), which raised the overall levels of intelligence (bottom arrow). The end result was this:

A similar loop exists for every “revolution” in human history. Take the Agricultural Revolution, for example. As usual, there was a J-curve involved…

…and the cause of that J-curve was a positive feedback loop: as more humans settled in one spot and raised crops for food, they were better able to defend themselves from predators and other humans. More humans meant more need for food, which necessitated more agriculture. 12,000 years and 7 billion humans later, contemporary civilization is what you get.

Unfortunately, a J-curve can also be the first half of an S-curve:

For any individual technology, progress is initially made quickly, but soon plateaus. Every positive feedback triggers a negative feedback loop, giving rise to a long period of stagnation following the dramatic takeoff. In the Agricultural Revolution, for example, rising populations brought about their own amelioration, as urbanization gave rise to new problems like epidemics and large-scale warfare. It’s too early to say whether the Industrial Revolution has met a similar fate, but chances are that it will at some point.

It’d be easy to blame negative feedback for societal ills, except for the fact that they precede as well as succeed positive feedback. Each expanse of stagnation prepares the way for the next positive feedback loop, when it inevitably arrives.