GROWING A SOCIETY :

Seeing Around Corners : The new science of artificial societies suggests that real ones are both more predictable and more surprising than we thought. Growing long-vanished civilizations and modern-day genocides on computers will probably never enable us to foresee the future in detail--but we might learn to anticipate the kinds of events that lie ahead, and where to look for interventions that might work (Jonathan Rauch, April 2002, Atlantic Monthly)

Growing artificial societies on computers--in silico, so to speak--requires quite a lot of computing power and, still more important, some sophisticated
modern programming languages, so the ability to do it is of recent vintage. Moreover, artificial societies do not belong to any one academic discipline, and their roots are, accordingly, difficult to trace. Clearly, however, one pioneer is Thomas C. Schelling, an economist who created a simple artificial neighborhood a generation ago.

Today Schelling is eighty years old. He looks younger than his age and is still active as an academic economist, currently at the University of Maryland. He and his wife, Alice, live in a light-filled house in Bethesda, Maryland, where I went to see him one day not long ago. Schelling is of medium height and slender, with a full head of iron-gray hair, big clear-framed eyeglasses, and a mild, soft-spoken manner. Unlike most other economists I've dealt with, Schelling customarily thinks about everyday questions of collective organization and disorganization, such as lunchroom seating and traffic jams. He tends to notice the ways in which complicated social patterns can emerge even when individual people are following very simple rules, and how those patterns can suddenly shift or even reverse as though of their own accord. Years ago, when he taught in a second-floor classroom at Harvard, he noticed that both of the building's two narrow stairwells--one at the front of the building, the other at the rear--were jammed during breaks with students laboriously jostling past one another in both directions. As an experiment, one day he asked his 10:00 A.M. class to begin taking the front stairway up and the back one down. "It took about three days," Schelling told me, "before the nine o'clock class learned you should always come up the front stairs and the eleven o'clock class always came down the back stairs"--without, so far as Schelling knew, any explicit instruction from the ten o'clock class. "I think they just forced the accommodation by changing the traffic pattern," Schelling said.

In the 1960s he grew interested in segregated neighborhoods. It was easy in America, he noticed, to find neighborhoods that were mostly or entirely black or white, and correspondingly difficult to find neighborhoods where neither race made up more than, say, three fourths of the total. "The distribution," he wrote in 1971, "is so U-shaped that it is virtually a choice of two extremes." That might, of course, have been a result of widespread racism, but Schelling suspected otherwise. "I had an intuition," he told me, "that you could get a lot more segregation than would be expected if you put people together and just let them interact."

One day in the late 1960s, on a flight from Chicago to Boston, he found himself with nothing to read and began doodling with pencil and paper. He drew a straight line and then "populated" it with Xs and Os. Then he decreed that each X and O wanted at least two of its six nearest neighbors to be of its own kind, and he began moving them around in ways that would make more of them content with their neighborhood. "It was slow going," he told me, "but by the time I got off the plane in Boston, I knew the results were interesting." When he got home, he and his eldest son, a coin collector, set out copper and zinc pennies (the latter were wartime relics) on a grid that resembled a checkerboard. "We'd look around and find a penny that wanted to move and figure out where it wanted to move to," he said. "I kept getting results that I found quite striking." [...]

Schelling's model implied that even the simplest of societies could produce outcomes that were simultaneously orderly and unintended: outcomes that were in no sense accidental, but also in no sense deliberate. "The interplay of individual choices, where unorganized segregation is concerned, is a complex system with collective results that bear no close relation to the individual intent," he wrote in 1969. In other words, even in this extremely crude little world, knowing individuals' intent does not allow you to foresee the social outcome, and knowing the social outcome does not give you an accurate picture of individuals' intent. Furthermore, the godlike outside observer--Schelling, or me, or you--is no more able to foresee what will happen than are the agents themselves. The only way to discover what pattern, if any, will emerge from a given set of rules and a particular starting point is to move the pennies around and watch the results.

If segregation arises naturally but unintentionally in this manner, the question for integrationists becomes : is it possible to change human nature so that people won't want to have even just a few neighbors who are "like" themselves? And the question for the rest of us is do we want to so change human nature? Posted by Orrin Judd at April 23, 2002 3:16 PM