Punctuated equilibria in DNA, silicon and society

R.E.M.’s Cuyahoga has long been one of my favourite songs. It became more poignant to me in 2003, when I moved to the area it’s roughly about and learned how literal the lines about “burn[ing] the river down” and “where they walked, swam, hunted, danced and sang”, but this isn’t what I want to write about today. What’s on my mind right now are the optimistic lines the song starts with before going there:

Let’s put our heads together and start a new country up

Our father’s father’s father tried, erased the parts he didn’t like

I think it’s a wonderful distillation of something that I both admire and fear about U.S. culture. The admiration comes from a sense that this is still a place where people are often willing to strike out and make something new instead of settling for the unsatisfactory. I do think that’s in some way inherited from the successive waves of immigrants, since they’re a group self-selected for their willingness to try this, and that it’s one of the reasons a disproportionate amount of interesting innovation comes from here.

The fear comes from at least two angles. One is that “erased the parts” is so very literal: European settlers wiped out the cultures and most of the people who came before them, and seem to have done a great job of dropping even the good parts of the cultures they themselves came from – in contemporary U.S. reactions to Europe I still see a lot of babies being thrown out with bathwater. The other is that the willingness to move on and start anew also means an excessive readiness to give up on what already exists, and a continual need to find new spaces to colonise, which necessarily means more people being displaced and more resources wasted by every move. The trouble is that there hasn’t been a real terra nullius since at least the Polynesian migration, and it’s more obvious than ever that we can’t afford to keep throwing away resources by starting our settlements over.

That’s a lot of meaning for two lines of a song, but R.E.M. were often dense like that. Anyway, I’ve been thinking about this because last Thursday Joe Brewer put on one of his periodic “Innovation Salons“. The theme was how systems thinking can inform a region’s innovation process, and appropriately much of the discussion was around the human factors involved. Larry Swanson said something about the willingness of American cities to radically reinvent their infrastructure. This led me to what I’ve written about so far in this post, though I also felt the need to object that there are long periods of conservatism—even active change resistance and a “can’t-do” attitude that refuses to believe change is possible—in between the bursts of radicalism. That tension between short bursts of amazing radical energy and long interstitial periods of conservatism, has been much on my mind since.

I’ve tended to interpret this very negatively, seeing it as a sign that change is only possible when things get bad enough, whether “bad enough” meant famines and/or religious persecution in the old country, or the Great Depression. I’ve been seeing the partial success of the Occupy movement as a symptom of this: on the one hand they seem to have got far more traction and broader sympathy than the anti-WTO protests of the late 90s, because the state of the world is palpably worse than then, but on the other they’re meeting plenty of public distaste because things aren’t quite bad enough or obviously enough so. But there is a more optimistic way of looking at this, by analogy with punctuated equilibria in evolution.

The idea of punctuated equilibria is that change in species over time is not a constant, gradual process, but rather that long periods of comparative stability—equilibria—are punctuated by bursts of change. The fossil record seems to imply that this is how biological evolution has worked, and it’s certainly something that shows up over and over again in simulated evolution. In biology this manifests itself as long periods during which few new species emerge, with the appearance of new species seeming to get concentrated into bands of time, the most famous being the Cambrian Explosion. Computer simulations tend to look at the evolution of individual species, and because fitness can be precisely measured in a computer model we get charts like this:

Chart of fitness over time, showing plateaus between discrete jumps
Image by Inman Harvey, from Scholarpedia

Obviously models tend to be very much tidier than anything we can observe in evolution, but even so the horizontal lines are a bit misleading. Deeper analysis shows that plenty of change happens during those stable-looking periods – it’s just that none of those changes improve the fitness of the species. What seems to go on in these periods is that evolution is exploring a Neutral Network: a set of genetic changes that don’t affect fitness, most often because they don’t outwardly affect the species at all. This is important because it’s how a species retains its diversity, and ultimately that diversity is what allows the next burst of change, either by finding the next improvement in fitness, or by making the species better able to adapt when the environment changes.

We know that a similar process does happen in biological evolution, and we know that this makes communities of real organisms more robust to environmental change. I’m not sure how to test for it happening within human societies, given that we’re looking for subtler sorts of innovation than genetic drift, but it’s interesting to think that it might. This begs a lot of questions; here are a few:

  • Does this sound like a plausible explanation for a country that has periods of radical change in its past, but seems intensely change-resistant today?
  • How could we test for this phenomenon, instead of me just waving my hands and saying it might happen?
  • Could a failure to explore neutral networks explain the fall of once-mighty societies that went from innovative to rigidly conservative, such as the USSR, Mediæval China and the earlier Arab Caliphates? Or am I pushing the analogy too far here?
  • If this is what’s going on, how can we make sure our society does explore the neutral network so it’s able to change when needed? What about when vested interests push back hard against any change that might hurt them, such as Obamacare and carbon pricing?
  • At the same time, if we’re going to promote readiness to change and accept change, how do we constrain the process enough to rein in the tendency to be colonial, abusive and wasteful, without stopping it dead?

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