Parable of the Polygons – a playable post on the shape of society

I enjoyed playing with the graphs and everything, but I question whether this model has much relevance to the real world. Is there a strong reason to believe that these effects would survive a model of "I want to move" that is not solely based on "too many people unlike me live near by" and/or "not enough people unlike me live near by"? Indeed, is there a strong reason to believe that a binary modality of "I'm happy/unhappy," (the post gestures in the direction of a third mode, "I'm neither happy nor unhappy," but in fact in their simulations that third mode is indistinguishable from "happy") is a good abstraction of people's moving decisions?

The data paper they posted a link to suggests that there is unlikely to be an equilibrium, contra the message of this post.

It seems like it's more an explanation of a mathematical model and a prescriptive political position, rather than a description of anything real in society.

Sociological studies have found this to happen pretty often. A (very readable) study of tipping points can be found in There Goes the Neighborhood (http://www.amazon.com/There-Goes-Neighborhood-Tensions-Neigh...).

Certainly it's a model but you can work up to more complex models. Check out NetLOGO, which comes with a huge library of simulations and a fairly friendly IDE for creating your own agent-based simulations.

There's no particular reason to desire an equilibrium, though. Actual desires should shift, which will naturally disrupt any equilibrium that appears, and this will probably happen faster than any equilibrium could be approached.

I think that as it's presented, the authors are suggesting that it's a model that is necessary and on some level sufficient to understand the dynamics of self-segregation in housing.

They subtitle the post "This is a story of how harmless choices can make a harmful world." Reading it, I get the powerful impression that the authors think that this model has the basic answers for all self-segregation in housing.

But obviously an even slightly more complicated model undermines many of their points. Like, they make a big deal of the idea that if you have a fairly high level of "shapism" and thus get a fairly segregated society, and then you lower the level of "shapsim," nothing changes unless you actively reverse your bias and move if your neighborhood is not diverse enough.

But clearly people don't only ever move for diversity reasons. Sometimes you move because you got a job or a SO that's far away. Sometimes you move because you can afford more or less living space. Sometimes you move because you have a child now and want to get into a good school zone. Or whatever. And if your preferences are now, compared to when you last moved, more tolerant, that WILL reduce the level of segregation of your society.

In fact, people probably move for economic or family reasons far MORE often than they move for diversity reasons.

I mean, that's not a small difference from their model. It's one of their major points! That, once segregated, societies won't become less segregated unless people actively work on it.

And, honestly, I don't think that the model holds at all unless you understand that people probably mostly use economic proxies for race over primarily making decisions based on race. For the most part, I don't think people are saying, "I don't want to move there, there's too many black people." They're saying, "I don't want to move there, it's too poor or too crime-ridden" or whatever. And yes, they may be exaggerating the extent to which it is poor or crime-ridden because they have internalized racist ideas about whether majority-black neighborhoods are poor or crime-ridden. But the point is, you can't really address this segregation by telling people to prefer mixed neighborhoods: you need to address the complex relationships of economics and race and how economic class affects neighborhoods and whatever.

Yes, but a major point of the article is that a durable equilibrium is reached and then that equilibrium does not shift as attitudes shift. If it's not true that an equilibrium is reached, then one of their three major wrapping-up points is not true.

That's not a conclusion I draw from it.

Which one of their three wrapping-up points wouldn't be true? #1 simply asks you not to be offended. #2 states that it's always a work-in-progress. #3 is a call to action.

Perhaps you're misreading #2?

It's #2, and I'm not misreading it.

I mean, let's be clear: you can very reasonably hold the belief that one needs to actively work to overcome past bias. But in #2, they're calling out to their model, and specifically this part of this post:

"See what doesn't happen? No change. No mixing back together. In a world where bias ever existed, being unbiased isn't enough! We're gonna need active measures."

But that's only true because their model includes an easily-reached equilibrium (and also because it doesn't include non-diversity-based reasons to move). If it didn't, then past bias would not cause future segregation -- the (in that case never-stable) present state of the world would reflect current biases, not long-past one.

And this is what I'm saying: they have a very simple model. They have a few fairly laudable (though perhaps not actually very effective) personal and political prescriptions. But if the personal and political prescriptions do apply to the real world, they don't do so through the agency of that model.

But they're not saying that people only move for diversity reasons. They're saying that one simple metric at a fairly low level could nevertheless give you drastic results, which is a counter-intuitive conclusion - most people expect output factors to be proportional to input factors.

Don't get hung up on the explanatory power of the model for real conditions - for the same reason you would not get hung up on the simplistic assumptions of most economic models, which often involve two variables and all other factors being held equal ('ceteris paribus'). People sometimes dismiss all economics because micro starts out from these extremely simple foundations rather than being fully reflective of the real world, but that's a bit like dismissing math because arithmetic is so basic.

So, if I've understood your point correctly, you're saying that the segregated state is the "easily-reached equilibrium", and that such a state is "unlikely" to come to pass in the real world? That doesn't sound right; I think I'm still misunderstanding you.

I agree with the last paragraph of what you've written here: models are always simplistic and they're definitely too hasty in their prescriptions: but I'm having trouble parsing the rest of what you're saying.

(Also, unrelated, how the fuck am I submitting too fast when I not only waited an hour but also changed computers and IPs in between comments? Is having a conversation no longer allowed on these fucking threads?)

The point of the model is to demonstrate that all else being equal, very tiny biases can explain continued segregation.

It's mainly a counter to the idea that enough people not caring about the racial makeup of where you live will lead to diversity in the face of even tiny amounts of bias in other parts of the population. If people want diversity, the only way it will happen is to actively promote it.

Of course other effects come into play too.

Yes, the segregated state is the easily-reached equilibrium (you can tell it's an equilibrium because people stop moving). And, to be clear, it's an equilibrium because people have actually stopped moving -- you could imagine a dynamic state of constant move where at any given time it's still very segregated.

And indeed, that is what the data paper that the article links at the bottom (http://smg.media.mit.edu/library/Clark.ResidentialSegregatio...) suggests is true: Because in the real world, diversity preferences are not symmetric. That is, "triangles" may want to live with 3+ other "triangles" around them, but "squares" don't also want 3+ other "squares," they want, say, 1+, or indeed they want 3+ "triangles." That prevents the static equilibrium that the simpler model predicts, and means that people keep moving. The dynamic "everyone's always moving" may still be segregated, but the point is, it does not have the same property that the article highlights of "everyone moved to a state they can live with, and now even if they would be comfortable with a more diverse neighborhood, nobody's moving and so no diverse neighborhood ever happens." Because they are still moving.

I don't have the expertise necessary to critique the data collection or manipulation of that paper, so perhaps it's wrong, but I'm taking it as provisionally true that they are correct that no equilibrium exists.