On cities, super-linearity, and ontological politics

"Laws" for cities?
Physisct Bettencourt and West claims to have discovered "laws" on why cities grow, or in the words of Geoffrey West himself:
We spend all this time thinking about cities in terms of their local details, their restaurants and museums and weather, I had this hunch that there was something more, that every city was also shaped by a set of hidden laws.” [Interview in New York Times, see below]
Being Physicist as they are, they like to claim they have discovered "laws" it seems, when in fact they have found interesting patterns through amassing data across many cities and then done a quite simple correlation exercise.

Before summarizing these patterns, one can question the usefulness of these studies, especially when it comes to the nitty-gritty everyday practice of city-making, city planning and politics of justice in which the "thinking about cities in terms of their local details" is important indeed to understand just how to materialize more emancipatory and just city-scapes. This becomes clear when "laws" about cities is set against the light of recent writings on African and Global South urbanism that strongly argue for a move away from all-encompassing theory about 'the city' based mainly on Western experience, towards a "broadening [of] our understanding of cities and their futures [...] to produce a cosmopolitan, postcolonial urban studies" (Robinson 2002: 533; see also e.g. Pieterse 2008; Robinson 2002; 2005; 2011; Simone 2004).

At the bottom I have added references to some of the peer-reviewed articles by Bettencourt and West, and also to my article with colleagues on our article on urban transitions and resilience that builds on these patterns to articulate aspects of urban resilience (in New Orleans, Phoenix and Cape Town). For an effective popular description of Bettencourt and West's research, see this article in New York Times, or this TED talk by Geoffrey West.

Patterns across quantified data of cities
Using, what seems to be basic maths, Bettencourt, West and colleagues amassed data on infrastructure (e.g. cable length), innovation (e.g. number of patents), and other 'social interaction' variables (e.g. crime, HIV-infected persons) and simply correlated this to city population size to 'discover' "laws". They conclude that city growth is related to the economy of scale (more people share the same infrastructure, like sewage pipes etc. They found that when a city doubles in size, it requires an increase in resources of only 85 percent (as they point out, this follows the same "laws" as in the biological world; as animals become bigger they need less pipes/blood vessels per kilogram of weight, shown in an earlier article by West lead by biologists before him). 

But, another factor of city growth is rate of innovation (where West notes that Jane Jacobs early on made these same observations):
"whenever a city doubles in size, every measure of economic activity, from construction spending to the amount of bank deposits,increases by approximately 15 percent per capita. It doesn’t matter how big the city is; the law remains the same. “This remarkable equation is why people move to the big city,” West says. “Because you can take the same person, and if you just move them to a city that’s twice as big, then all of a sudden they’ll do 15 percent more of everything that we can measure.” [New York Times article]
The reason, they claim, lies in the larger intensity of social interaction that bigger cities generate. However, the same process generates other outcomes of social interaction, such as crime and HIV/AIDS-infected persons:
"After a city doubles in size, it also experiences a 15 percent per capita increase in violent crimes, traffic and AIDS cases. (Of course, these trends are only true in general. Some cities can bend the equations with additional cops or strict pollution regulations.) “What this tells you is that you can’t get the economic growth without a parallel growth in the spread of things we don’t want,” Bettencourt says. “When you double the population, everything that’s related to the social network goes up by the same percentage.”" [NYT article.]
Processes behind patterns - social network effects?
To re-iterate this (but without talking about "laws", but more truthfully about patterns), we write in Ernstson et al. 2010 "Urban transitions: on urban resilience... and human-dominated ecosystems" (Ambio):

"In support of our third argument, we turn to Bettencourt and colleagues (Bettencourt et al. 2007 which includes West) who recently measured how the size of a city scales with a range of different indicators reflecting the role of energy, population and information in urban dynamics. Using population as the measure of city size, these indicators revealed three important patterns:
Proxies for energy consumption scale sub-linearly with urban size, indicating that when cities grow, they become more energy efficient;
• As is to be expected, the number of basic service providers (bakeries, schools, etc.) scales linearly with urban size;
Surprisingly however, the proxies related to innovation and new wealth creation (such as number of patents, number of employees in research, and wealth per capita) scale super-linearly with urban size, i.e., increase faster than the population (along with more negative social indicators such as crime rate and HIV- infected persons).
This indicates that a key driver behind urban growth is innovation (not just economies of scale in energy consumption). Further, through its tight linkage to economic value creation, urban innovation, especially technical innovation as measured here, is in large part responsible for the attractiveness of a city, i.e., the degree to which individual stakeholders are willing to locate there, to invest in it, and to collaborate with others in it; a process that consequently drives the emergence and development of social networks. [...] 
However, to harness urban innovation, we need to understand why innovation is more pronounced in cities than in rural areas. The answer lies in the concentration of population in cities: the more people interact through recursive alignment processes, the more cognitive dimensions exist within the interactive group, leading to that more problems can be tackled with quicker accumulation of knowledge. This in turn allows the cognition of new problems and even more generation of knowledge in a continuous feedback loop (cf. van der Leeuw and McGlade 1993; van der Leeuw and Aschan-Leygonie 2005).
Based on a social network model of cities, Arbesman, Kleinberg and Strogatz (Arbesman et al. 2009) take this explanation further. They argue (with reference to Granovetter 1973) that bigger cities generate more innovations because they generate more interaction between people that are socially distant to each other (i.e., not family or friends). Such long-distance (or weak) ties means that information that has not met before, meets more frequently the bigger the city is, which aggregates to increased innovation at the urban level (Arbesman et al. 2009).4"
What about cities in Africa?
However, as I understand it, the underlying data of Bettencourt and West do not use data from cities in Africa or the Global South that have larger 'informal economies'. Maybe the underlying principle is still correct, but it might be more difficult to show. How do you measure innovation in a city where most innovation happen in and through the 'informal sector'? I am quite sure thought that the data that Andrew Charman, Leif Petersen and Laurence Piper at Sustainable Livelihoods Foundation are generating on the density of (informal) entrepreneurs in Cape Town could be interpreted in the light of West and Bettencourt. 

What about politics and details?
For West and Bettencourt, the city is an abstraction. And they are amazingly good in treating the general properties of this abstraction; the city to them come as aggregated statistics collected in databases they have found across the world. They state that every city need to live according the the 'laws' they have discovered, although recognizing that certain cities can 'bend' these laws so as to have less crime, or more innovation, that what the laws would predict. However, how to "bend" these laws in individual cities would then be where urban politics sets in. 

Furthermore, their cities are also a-historical since they do not need history to explain anything in the abstract. Needless to say, as "West considers urban theory to be a field without principles, comparing it to physics before Kepler pioneered the laws of planetary motion in the 17th century", we should recall that to "bend the laws" of West and Bettencourt, for instance in lowering crime, or increasing justice, we will need situated and historicized accounts of particular cities to understand how politics towards these normative goals can be achieved through material political practice and activism.

Ontological politics
However, one could go further and state that what is also in-the-making -- through the amassing data, correlating data, publishing in PNAS, giving talks at TED, and being interviewed in New York Times -- is an ontological politics; about creating 'the city' as a knowable thing and in presenting objective knowledge about this thing to the world. In doing so, you will also present yourself as the bearer of legitimate knowledge for this thing, thus winning epistemological battles, and aligning a whole set of knowledge practices such as data-crunching, computer models, and quantifiable knowledge, while ruling out other knowledge practices, such as in-depth and rich ethnographic descriptions of city-making (see e.g. Simone 2004).

This turns the spotlight on the increasing knowledge production around cities and urbanization through books, articles, conferences, TED-talks and the like. The question then is how this kind of "laws" become spread by researchers and policy folks (and those viewing TED to "stay in the know", in fields they do not know in-depth). And how such knowledge claims (and equally how other forms of knowledge-claims about cities) come to support/create forms of urban governing, or governmentality? Which forms of governing, for instance, are supported by knowledge-claims dressed up as "laws"? How are such knowledge-claims met, critiqued and rebutted in academic debates and in practice?


Bettencourt, L. M. A., Lobo, J., Helbing, D., K├╝hnert, C., West, G. B., 2007, Growth, innovation, scaling, and the pace of life in cities, PNAS 104(17):7301-7306.
Bettencourt, L. M. A., Lobo, J., Strumsky, D., 2006, Invention in the city: Increasing returns to patenting as a scaling function of metropolitan size, Research Policy 36:107-120.
Pieterse, E., 2008, City Futures: Confronting the Crisis of Urban Development, in: Global Issues Series, Zed Books, London.
Robinson, J., 2002, Global and world cities: a view from off the map, International Journal of Urban and Regional Research 26:531-554.
Robinson, J., 2005, Urban geography: world cities, or a world of cities, Progress in Human Geography 29:757-765.
Robinson, J., 2011, Cities in a World of Cities: The Comparative Gesture, International Journal of Urban and Regional Research 35:1-23.
Simone, A. (2004). For the City Yet to Come: Changing African Life in Four Cities. London and Durham: Duke University Press

A related site to the type of research pursued by Bettencourt and West is here: 
"A Science of Cities" <http://www.complexcity.info/>


laurencepiper said…
fascinating stuff henrik - especially the innovative benefits of growth...

suspect that there will be a problem with the accuracy of data on cities of the south, not just africa - but quite like the metaphor of politics as about the 'bend' in the 'law'. that rings true!

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