The papers have recently been full of stories about yet another interesting pattern that researchers have gleaned from the data collected in the Framingham heart study. You can get a taste for the result by watching this annimation. What is shows is a social network (genetic and friends) changing over time. The primary focus of attention is body fat, and over time the member of this community get fatter, a lot fatter.

The sound bite associated with this study is that fat is contagious; and indeed the study showed that friends of fat folk had a higher likelihood of becoming fat than other people. Social networks exhibit a tremendous amount of “birds of feather flock together.” If I buy an conditioner, take up bicycling, start wearing a hat, or take a particular political position it is likely that I am following the lead of some of my friends and that my choice will lead others to come along.

While all behavior is socially viral I am troubled by the way that lots of people have gotten the impression that this study proves that weight gain is viral; i.e. the association with fat people is effectively dangerous because becoming fat is dangerous. I have trouble seeing how that conclusion isn’t exactly like the presumption that association with poor people (think here of the local high school) is likely to make you poor. While both of these may well have a modicum of truth to them the puzzle is exactly how concerned about the risk should a person be?

Reading the paper I’m struck by the apparent absence of references to other work on how ideas, behaviors, and real viruses spread across social networks. I.e. there id no framing of exactly how contagious this effect is relative to other things.

I’d love to see similar animations for other behavioral affectations. For example people who own air conditioners, folks who drive large cars, eating out at chain restaurants. It is inconceivable that the modern marketing industry doesn’t have reams of data like that. The this study is looking at something with a strong health component colors how we think about this. If the same data showed internet usage, or cell phone adoption, then we would presume that the primary driver certainly as much or entirely techo-economic rather than dragging in questions of individual will and infection. Of course ideas like choice, memes, viral spread would remain interesting but the wouldn’t be so highly energized.

Causality is very complex stuff; but I don’t see how this study is a big help in getting at the root causes of obesity. If we had a similar drawing that showed the association with internet users substantially increased the chance of adopting becoming an internet user would we announce that it was contagious? What about gun ownership? What about being a Republican? This animation looks to me like a simple illustration of how a behavior gains market share; i.e. decreasing barriers to adoption enable increased market share. That adoption trickles across the social network seems mind bogglingly obvious and actually quite unexceptional.

I’ve thought and read about cities for decades so it is extremely cool to encounter a new idea.  I’m currently on vacation in Ithaca NY, and before hand I wandered into the Architecture library at work to pick up a book about the Finger Lakes region.    That book was a disappointment, but nearby was a big thick book confidently called City about New Haven Connecticut and as is my wont I picked it up too.  City: Urbanism and Its End by Douglas Rae adds two new, to me, pieces to the puzzle of what happened to the American cities.

My father used to tell a story about a scholarly study of what climate is most suited to civilization.  The scholars plotted latitude of the great civilizations down through the ages.  Fitting a curve to their data they showed conclusively that the current optimal location of a civilization was New Haven Connecticut.  Needless to say the scholars were at Yale.  I grabbed the book in the hope it would turn out my father’s story wasn’t entirely tongue and cheek.

Geography does shape civilizations of course.  The presumption that Yankee thrift and innovation is a consequence of the Puritan culture, to take a common example, is thrown into question by the story of how the Puritans who migrated to Central America at the same time  ended up being slave owning oligarchs.  In that case the distinguishing factor appears to be labor availability.  In New England labor was dear, land wasn’t; while in the Central America it was the other way around.  Dear and innovation go hand and hand.

The thesis of “City: Urbanism and Its End,” beautifully and delicately presented in the first chapter, states that cities, like New Haven, made sense as a coordinating device only for a short period, less than a century.  It’s conventional to say that the automobile killed the center cities and in models of that kind the primary driver of how concentrated our settlements are is the transportation system used to glue them together.  Old cities in Italy have narrow streets because they were used on foot while modern urban spaces care more about tractor-trailers than tricycles.

The usual complement to the transportation based models of city concentration are ones about endowment.  First there were the natural endowments, a good and defensible harbor or along an existing trade route for example early London or New York’s are examples of that.    Later cities became their own endowment; aggregating social networks, capital, functional governance, etc. etc.  San Jose, and Silicon Value, is a modern example and Venice or Amsterdam a older one.  This model of cities as aggregating increasing returns in their endowments is my preferred model for what shapes the concentration of populations into cities; in part because it seems to fit well the power-law distribution of city sizes.

In the years prior to the rise of cities like New Haven the population was concentrating into what he calls Fall Line Cities, i.e. cities build along a river that was rapidly descending so as to take advantage of water power.  Labor, capital, expertise, the whole complex knot needed to make industrialism work, had to migrated to the power source.  That changed with the advent of steam power, railroads, coal, etc.

So that’s new to me.  Energy was no longer dear, or at least no longer immovable,it could no longer command all the other elements of the party to show up where ever it happened to be.  Once energy stopped being the key endowment other factors became the hard thing coordinate.  The city became the party.  One consequence of that insight is to wake up to the key role that electricity plays in blowing apart the 20th century central city.  It is, possibly, just a critical to the story as the automobile.  Before electricity you wanted to be near a rail or flat water to get your coal, to run your steam engines.  This reminded me of another of my father’s stories.  He had a friend who started a company making fiber optics, and that factory was carefully sited to be adjacent to a high tension power line near a small New England town with a concentration of optics expertise.

But there is yet another part to the story that is new to me.  Some years ago I was shocked to watch how real estate interests in Massachusetts were able to override the governance of the states principle cities using a statewide proposition.  Rae highlights how cities are seriously handicapped in the US by how their governance is structured.  In 1907 the Supreme Court wrote: “The State .. at its pleasure may modify or withdraw all [city] powers, may take without compensation [city] property, hold it itself, or vest it in other agencies, expand or contract the territorial area, unit the whole or a part of it with another municipality, repeal the charter and destroy the corporation.  All this maybe done, conditionally or unconditionally, with or without the consent o the citizens, or even against their protest.  In all these respects the State is supreme.”

That’s why, for example, suburban and rural voters could pass a referendum over the objections of city dwellers in Massachusetts.  That’s why New York city can’t get it’s hands on a half a Billion dollars from the feds for congestion pricing without sharing a large portion of the money with the rest of New York state.  Why New York is attacked by terrorists and we send money not to cities but to states where it buys toys for rural police departments rather than improved harbor security.  It’s why when the automobile began to undermine the numerous endowments that cities has accumulated they had such a hard time fighting back; and it goes a long way toward explaining why European cities were more successful in tempering the displacement of those endowments.

Of all the endowments cities have the diversity and richness their social and knowledge networks are the ones I find most fascinating.  My father’s friend needed electricity and a pool of optics expertise he could draw upon.  I’ve thought that eBay and Google couldn’t have happened in any other situation; they desperately needed the pool of expertise that only the bay area could provide.  These endowments are the ones that Jane Jacob’s emphasises in her works.  By the time she was writing cities were created innovation but as firms grew they threw their factories out into the periphery.  Just as Apple manufactures in Taiwan, or Google puts it’s servers next to hydroelectric plants.  It is, just possible, that the Internet will displace these social/knowledge endowment as well.  While I don’t know how that will play out for cities what I do know is that it’s harder than it looks replicating those in on the fabric provided by the net.

I suspect we all know, but I just what to be sure it’s on the record, that Long Tail ideas suffer from the Base Rate Fallacy.

Which is to say that stocking more products in your store, more books on the library shelf, more details in your server logs, or keeping more of your options open does not automatically lead to a better experience. Unless of course you enjoy searching, sorting, organizing, or hording.