This is an Urbanscale Article titled “Of sidewalks and signals: Learning to listen on the urban frequency,” written by Adam Greenfield in New York City on the 11th of January 2012.

My contribution to the catalogue for Invisible Fields, an innovative show on the “geographies of radio waves” José Luis de Vicente and Honor Harger put together last year. Attentive readers may recognize one or two familiar passages. The accompanying image is a frame from one of Timo Arnall’s short films, shot off a monitor on which it was playing during the show’s run at Barcelona’s Arts Santa Mònica.

When I say the word city, what’s the first thing you think of?

For most of us, I’d wager, the word conjures up images of things that are for the most part just that: things, physical facts. Judging from the friends, students and total strangers of whom I ask this question, anyway, our initial impressions tend to be oddly static dioramas, mute arrays of buildings and streets and sidewalks; only after a moment, if at all, do we remember the unceasing flows of people that animate a place and make it what it is. And this is likely to be true whether our first thought happens to be of Grand Central Station, Shibuya crossing, the choked streets of Lagos or the markets of Bangkok.

Two lenses, then. Through one, the city is coextensive with its stones and monuments, more or less independent of the acts that take place among them; through the other, it’s nothing other than the sum of those acts. If you’re like me, you may be disposed to think that one of these two ways of describing a place has by far the deeper claim on truth — and it isn’t the former.

So what are we to make of the invisible electromagnetic sleet that attends any human place, this pulsing cloud of signal that threatens to exhaust my store of metaphors and which it’s already half a cliché to discuss? Doesn’t any consideration of this belong to the city of stones?

Well, maybe. Just maybe, if the inquiry is confined to the physics of signal absorption in densely built-up areas, the differentials of attenuation in concrete and brick. But even there, the all-too-human isn’t far beneath the surface. Because literally anything beyond the very simplest question in the domain — whether we’re concerned with the placement of relays to ensure line-of-sight propagation or the politics of spectrum allocation — is bound to invoke the presence of human actors and institutions, our values and our priorities. We’re always already present in the Hertzian city.

And inevitably, no matter how ghostly or immaterial it may be, the veil of electromagnetic traffic that suffuses a city is going to have implications for the visible behavior of the people in it — interestingly enough, in ways that diminish the relative significance of the built environment. Any close observer of human behavior in the contemporary city will have noticed that our decisions are no longer informed entirely, or even predominantly, by our physical surroundings. The quality which now conditions choice and action belongs primarily to the region of the electromagnetic spectrum that lies roughly between 3 MHz and 64 GHz: the domain of microwave transmissions, mobile telephony, and WiFi networks.

If you doubt the claim to determinism here, you need go no further than the nearest busy sidewalk to garner evidence in its favor. Note how many of the people you see are quite literally receiving instructions from the aether. How many of them are turning at this corner because that’s what Google’s walking directions specified? How many are following some gradient of ostensible hipness dictated by a social-location service? And how many are about to step heedlessly into traffic, because they’re more present in the nonplace of their phone conversation than they are in the onrushing here and now?

Watch what happens at any subway entrance, any time a train comes in, as passengers emerge from the signal-free purgatory of the underground and immediately reestablish their presence on the network. Observe the behavior of workers leaving an office building at the end of the day, as they say their goodbyes to their colleagues and don headsets for the journey home.

Now compare what you see to William H. Whyte’s classic time-and-motion studies of the Midtown Manhattan of the 1980s, collected in The Social Life of Small Urban Spaces. Spend even a few minutes watching Whyte’s video — you can find it on Vimeo, if you’re so inclined, stream it to your phone as you walk down the street — and you cannot help but notice how differently people once lived the city, and not so very long ago.

Before pulling the dense shroud of connectivity over ourselves and our cities, people used to be co-present, at least in potential. They were available to one another, in ways we’ve largely ceased to be, and it shaped their microbehavior in ten thousand unconscious ways, from the things they carried to the way they held their bodies and moved through space. We’re very close here to William Gibson’s observation that “some very considerable part of the gestural language of public places, that had once belonged to cigarettes, now belonged to phones.”

If you still doubt the thesis, you can simply pay close attention to the people headed back into the subway. In my talks, I very often tell the story of something I saw in Hong Kong over ten years ago now: a series of young women moving briskly through the turnstiles of the MTR, swinging their handbags in the air with balletic grace as they did so.

What were they doing? They were using the system’s RFID-equipped Octopus farecards — using them brilliantly and intuitively, but in a way that system’s architects had never foreseen.

These architects most likely imagined that people would use their cards in the conventional manner, by tapping the card neatly against a turnstile-mounted reader. At some point soon after the system’s introduction, however, one or another canny passenger obviously figured out that they didn’t have to do this: because the reader was powerful enough to acquire and read an antenna tens of centimeters away, even through layers of fabric, they could leave the card wherever it was most convenient for them, and never have to fish it out at all.

The result wasn’t merely the elegant gesture I’d seen enacted time and again. Because the elaborate interaction between card and turnstile, turnstile and database, database and barrier had been compressed into the third of a second it might take someone to swing their handbag through a reader field, each one of the women I’d seen was able to move through the process of fare collection and into the subway without breaking her normal walking pace. And this, in turn, markedly improved the number of passengers the station could accommodate in a given period of time, what traffic-analysis engineers call “throughput.”

There turns out to be a surprisingly close coupling between parameters of a system’s technical operation and the kinds of behavior that arise in response to it, as I learned when I related this anecdote in the course of a talk I gave in Tokyo a year or so later. During the Q&A session, someone in the audience pointed out that one of that city’s major public transit systems, JR East, also offered its customers an RFID-based smartcard, called Suica…and yet he’d never seen women in Tokyo making the handbag gesture I’d described. And he asked the obvious question: Why not?

I had to confess that I didn’t know. As it turned out, though, someone in the audience that day did. As she explained it, the designers of the Suica system, acting out of concern over the long-term health implications of radio-frequency fields for human users, had deliberately lowered the power of their readers, and therefore abbreviated their system’s range. No range, no handbag ballet, and an entirely different rhythm at the turnstile.

And here we get to the crux of the issue: in both Hong Kong and Tokyo, the consequences of decisions made by engineers about the properties of a technical system operating in the electromagnetic spectrum cascaded upward not merely to the level at which they could afford or constrain individual behavior, but that at which they affected the macro-level performance of the entire subway system.

Similar things are true at the larger scale of social activity, as well. If “city people are constantly making and ‘unmaking’ places by talking about them,” as geographer Yi-Fu Tuan argues, and “[a] network of gossip can elevate one shop to prominence and consign another to oblivion,” how could it not matter that such communication now propagates across the urban fabric at the speed of light? The terms on which this “gossip” is conducted, its persistence and its domain of effect, have all been altered beyond recognition. What people are saying online, how they rate the businesses around them, which social networks the customers of those businesses happen to use — these are the things which now tell.

You don’t have to like what this all implies. Most days I myself do not. But if you care about cities and what people can do with them, you do need to understand what’s going on here:

The irritating guy with the popped collar standing next to you at the bar? He paid less for his G&T than you did, because he’s the Mayor of this place on Foursquare, and the management has cannily decreed Mayors get a 5% discount. Ten minutes from now, the place is going to fill up with his equally annoying buddies, absolutely ruining your hope of a quiet drink. And they’re going to show up not because he did so much as call them to tell them where he’d be, but because he’s got things set so his Foursquare account automatically posts to his Facebook page. Buddies of his that don’t even use Foursquare will come, to slouch at the bar, stab at their phones and try and figure out where the party’s going next.

You’ll settle up and leave, miffed, and ease on down the road a spell to a place you know where you can get a decent bowl of penne — nothing special, but good and hearty and cheap, and you’ll chase it with the big bouncy house red, and all will be well and right with the world. Except the Italian place is gone, gone because it racked up too many nasty reviews on Yelp, or somebody Googlebombed its listing, or its hundred healthcode violations made it positively radioactive on Everyblock.

Two years from now, these names will most likely be different. But the point will remain: if the technologies these services are built on are opaque to you, if you don’t know what they are and how they work, you’ll never have the foggiest clue why things shook out the way they did. Your evening will have a completely different shape and texture than what it would have prior to their advent. You’ll have been tossed this way and that by gusts and squalls blowing in a parallel dimension, whose sole physical trace is modulations of a signal imperceptible to the human sensorium.

Of course, you could just as easily argue that your evening out would have been inflected in all sorts of delightful ways by these prevailing winds. Either way, though: inflected it will be. The trouble is that these effects, which do so much to shape the experience of the contemporary urban environment, are produced by a series of institutional and individual actors with relatively little feel for the unique complications of that environment.

Put bluntly, engineers aren’t paid to care about high-quality urban experiences. They’re given a series of constraints — physical, technical and economic — and within these constraints they are responsible for devising an optimal solution. Requiring that the solution they arrive at be something that underwrites a congenial, humane environment is not generally among the criteria they are issued.

Worse, designers of informatic systems have tended to treat the ground on which their systems take effect as what Deleuze called “any-space-whatever”: an abstract, generic, unconditioned space at degree zero, containing infinite potentials for connection. But as more sensitive observers — I think of writers like Paul Dourish and Malcolm McCullough — take pains to point out, this can never be so. Space is always some particular space, technical systems are always given meaning by being situated in a specific locale and human community.

Meanwhile, the urbanists that might have supplied technologists with vital corrective insight have tended to be far from the cutting edge of technical development, in their turn unfamiliar with the impact of things like mobile phone use on cities and their users. As urbanist discourse has embraced ideas like transit-oriented development, traffic calming and urban wetlands, it has lacked any account of the ways in which the behavior of people in cities has changed over the past quarter-century, largely due to the influence of the technologies we’ve discussed. All of these things, to be sure, are entirely laudable ends to work toward…but none of them does a damn thing to respond to the novel circumstances we now find ourselves in, as residents and users of cities.

What we need now, acutely, is a generation of technologists who understand the texture and nuance of city life, and, in parallel, a generation of urbanists with some nous for the technologies that now do so much to shape that life. Perhaps together, they can offer us a third and unifying lens, a lens through which the city of stones and the city as lived can be seen to be one and the same place. Endmark