Experiment № 044 · The story
Schelling's Segregation
Why I picked it
Almost everything in this collection so far grows out of physics or geometry — spins, waves, sand, fractals. I wanted one built out of people instead, and this is the most quietly unsettling result I know. In 1971 the economist Thomas Schelling asked a simple question: what would it take for a perfectly mixed neighbourhood to sort itself into separate blocks? He assumed you'd need real hostility. The answer he found — work later folded into a Nobel Prize — was the opposite, and it has stuck with me for years. I wanted to be able to drag the slider myself and watch it happen.
What I enjoy about it
The tolerance slider. Every agent here is remarkably easygoing: set it to 33% and each one is perfectly content to be a minority, outnumbered two-to-one by the other colour, and only twitches if it drops below that. Nobody wants segregation. Yet let it run and the salt-and-pepper mixture curdles into big single-colour continents anyway — and the “segregation” meter climbs to 70, 80%. Crank the slider up toward wanting a majority and it doesn't get gently worse; it collapses. Push it down to near-zero and the mixture holds its ground. There's a threshold in there you can feel with your thumb.
Something you might take away
A pattern in a crowd is not proof of a matching intention behind it. The final map looks like the work of people who desperately wanted to be apart — but the only rule in the model is “don't be too outnumbered,” and that mild, individually reasonable wish is enough, all on its own, to sort the whole world. Before reading a collective outcome as a collective desire, it's worth asking what the smallest individual preference is that would produce the very same picture. Surprisingly often, it's far smaller than the picture makes it look.