Start by Observing the World
Looking around, one finds humans more or less sorted into groups of similar
people. Most readily noticed when the sorting occurs in terms of racial
and ethnic features, there are all sorts of other ways that people also
cluster in terms of similar characteristics. It is unlikely that there
is a simple single cause for the sorting in any one case, much less that
there is the same, single, simple cause for all of them. At the same time,
it's curious that a similar phenomenon occurs in lots of different contexts,
and one wonders whether there might be something similar that is contributing
to all of them.
Ask A Question: Why Segregation?
An obvious possibility is that people have a preference for associating
with people like themselves. One might well suspect that this would by
itself lead to clustering, but the intuition is vague. In situations like
this, an explicit model can be helpful, not only to verify the intuition,
but to provide a way of addressing some further questions.
Thomas C. Schelling, an economist, was interested in the 1960's in patterns
of racial segregation and integration in American cities, and came up
with such a model. Schelling's model, published in 1971, led to conclusions
that surprised people at the time, and for this reason became one exemplar
of modeling as a way of exploration. At the time, Schelling could use
only paper, pencil, and objects to work out the outcomes of his assumptions
(for another example of a model developed before computers were available,
see Conway's Game of Life). Since
then, it has become possible to work out these consequences much more
rapidly.
Explore the Question
In this exhibit we provide a computer
implementation of Schelling's model and some modifications of it.
The model is quite simple and straightforward: five
easy steps. That's all you need to know to discover for yourself some
of the basic (and surprising) conclusions that Schelling, and others working
with the model, were able to reach. See what you discover. And if you
get interested, there's a more sophisticated
version of the model that will allow you to explore some other variations.
We've also provided a page that lists some
of the important conclusions that Schelling and others reached. But
don't look at that until you've done some exploring yourself, and reached
your own conclusions. Enjoy!

Ready to go? Click on the
Basic Model to get started. There you can learn about the basic structure of the model, get some tips for first using it and ... use the model to explore some initial questions:
Is there more clustering if peoples' preference for being with similar
people is greater?
What is the relation between the strength of preference and and the amount
of clustering?
How dependent are the answers to these questions on population density?
What happens if people prefer to be around people different from instead
of similar to themselves?
Then you can go on to
Some Implications of the Model
(Warning: Partial Spoiler! Play before you Look, and then play some
more, and then think about what you've seen, and THEN look to see what other people saw and whether its the same of different)
Some Tips for Further Exploration and Drawing Conclusions
An Advanced Model
Some Useful References
Online Forum For
Posting
Results and Comments
