As you might have guessed from several of my recent posts, I have been digging a lot into the literature on complexity science and chaos theory lately. You've probably heard of the so-called "Butterfly Effect" (see also the famous poem, whose author is unknown, "For want of a nail"), which I have posted about in the past (see "Butterflies"). In short, the MIT meteorologist Edward Lorenz stumbled on what has come to be called the "Butterfly Effect" while conducting a weather simulation in 1961. Lorenz had programmed an early computer (called a Royal McBee) using 12 mathematical equations to try to see if he could develop a model that would predict the weather. He surreptitiously stopped one of the trials of the simulation in the middle, replacing some of the normal six-digit variables with three-digit variables (he basically rounded) instead. To his surprise, this very small change in starting conditions produced dramatically different results. He metaphorically compared his discovery to a butterfly flapping its wings in Brazil and causing a tornado in Texas.
If you are interested in science fiction, I highly recommend a 1952 short story by Ray Bradbury called "A Sound of Thunder", which also involves a butterfly that ends up changing the course of history. With the "Butterfly Effect" in mind, I recently came across a book called, Flirting with Disaster: Why Accidents are Rarely Accidental by Marc Gerstein and Michael Ellsberg. There's a great chapter early in the book with a catchy title, "Butterfly wings and stone heads: How complexity influences catastrophe in policy decisions." The chapter's key take-home message is that in the world we live in today, i.e. a VUCAT world (one that is characterized by volatility, uncertainty, complexity, ambiguity, and turbulence), small changes in practice or seemingly minor decisions can sometimes have dramatic and often unintended consequences. The authors talk about a very well-known model in sociology called the Schelling Segregation Model developed by the economist Thomas Schelling (see the article, "The Math of Segregation" in the journal American Scientist for a great overview). While I may talk more about this model in the future, in today's post I want to cover one of the cases discussed in the second half of the chapter (I will talk about the second case in another post).
The first case (actually it was the second case mentioned in the chapter, but I want to cover this one first) involves Easter Island (also known as Rapa Nui - Dutch explorers gave the island its common name because it was "discovered" on Easter Sunday in 1722), an island in the southeastern Pacific that is a special territory of Chile. The island is most famous for its nearly 1,000 monumental stone statues, called moai, which were created by the early Rapa Nui people (one of the moai played a prominent role in the storyline of the 2006 film Night at the Museum).
The story behind the moai is absolutely fascinating! These monolithic human figurines were carved out of volcanic rock more than 500 years ago. While the tallest moai known is almost 10 meters high and weighs just over 80 tons, the average height and weight is about 4 meters and 14 tons, respectively. More than 900 of these stone statues exist, though statues are still being discovered even today. What is amazing is that the statues were carved in a quarry near the center of the island and then moved into position around the island's perimeter. These statues are often referred to as "Easter Island Heads" because of the disproportionate size of their heads and the fact that most of them were found buried up to the shoulders. Archaeologists today feel that the moai were a representation of the Rapa Nui's ancestors and deities. The heads actually face away from the ocean and "look" to the center of the island, keeping watch over the Rapa Nui villages and people.
Easter Island is one of the world's most remote inhabited islands (Chile is just over 2,100 miles to the East), and the nearest inhabited island is Pitcairn Island, with just about 50 residents in 2023 located 1,300 miles away (Pitcairn Island is most famous as the landing site for Fletcher Christian and the rest of the mutineers made famous in the Mutiny on the Bounty). Approximately 8,000 people live on the island as of 2023. Today, the island is mostly barren with few native species of birds, but that wasn't always the case. Easter Island was once home to lush and diverse forests, specifically a now extinct species of palm tree, and it was home to several large colonies of sea- and land-birds. The birds are long gone as well.
While scientists today can surmise how (and perhaps why) the moai were built, they still don't know for sure about what happened to the Rapa Nui people. Here is where things get a little interesting (and a little controversial). The American scientist and writer Jared Diamond claims in his book Collapse: How Societies Choose to Failor Succeed that the Rapa Nui society on Easter Island collapsed due to environmental damage caused by humans (he also blames environmental causes to the collapse of society on Pitcairn Island, but that may be a greater stretch). Some scientists blame the moai on the collapse of the Rapa Nui society. Building these large statues became somewhat of an obsession, with tribal chiefs competing with each other over who could build the largest and most complex moai. The Rapa Nui islanders used the palm trees that covered the island to create the logs, ropes, and sleds used to move these large statues from the quarries in the center of the island to their final positions. The palm trees took up to 100 years to reach adult height, and unfortunately the trees were cut down faster than they could be replaced. Without trees, the ecology collapsed. The loss of the trees led to the collapse of the bird population. No trees meant less rain (apparently tree growth and rainfall are mutually interdependent) and more soil erosion and greater water runoff. Crop yields tumbled. Without trees, the Rapa Nui no longer had wood for their cooking fires, canoes, and shelters. As food and water became more scarce, the different tribes of Rapa Nui started to fight. Soon, the entire society on Rapa Nui collapsed as well.
As Marc Gerstein and Michael Ellsberg write, "It would have been impossible to conceive that one day an islander would cut down the very last tree and, with that act, one thousand years of civilization would collapse soon thereafter." Diamond's theory (he calls it "ecocide") sounds a lot like the poem mentioned above, "For want of a nail". I have to point out that many scientists do not agree with his theory, claiming that the population of people on Rapa Nui slowly decreased over many years (see Terry Hunt's article, "Rethinking the Fall of Easter Island" that appeared in the journal American Scientist). The truth, as it usually does, likely falls somewhere in the middle of the two opposing theories.
Regardless of who is correct here, I really think that this story is yet another good example of the concepts I've been discussing in several of my recent posts on complexity theory and complex adaptive systems. The "Butterfly Effect" reminds us that every decision we make counts, regardless of its scale. Even the most insignificant choices can sometimes have profound consequences.
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