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  If you calculate integration coefficients for an entire region, the numbers can be represented nicely by using the heaviness of the lines on the map to represent the integration coefficient of each street. The heaviest lines have the highest coefficients, or highest integration, in other words. Shown in Figure 12 is such a map for my own neighborhood.13

  Figure 12: A map of my neighbourhood, showing areas of highest coefficiency using heaviest lines

  The most interesting thing about these maps of integration coefficients, and the reason that I’ve burdened you with the details of how they are constructed, is that they work remarkably well to predict how we behave in space. People (and cars) tend to congregate at regions of high integration. In fact, such measures work so well that Bill Hillier’s group has built a successful private consultancy that uses the principles of space syntax analysis to help cities plan buildings, streets, and neighborhoods in ways that promote desirable traffic patterns, both pedestrian and vehicular.

  You might notice that there are some similarities between the analyses of space that I’m describing here and isovists. In both cases, some simple generalizations about the shape of space are being used to describe and predict how we behave in space. Notice as well that in both cases, we don’t even need to describe how space is being used to make predictions about where we will find collections of people in a space. In the case of space syntax, there is a remarkable tendency for people to be found in the greatest numbers in areas of a city that have the highest integration values. The more connected an area is to the rest of the city, the busier it is likely to be.

  Space syntax analyses such as these are not only useful tools for those in the business of designing city spaces. They also connect with our own mental maps of space. In one illustrative study, researchers knocked on doors in an area of London and asked respondents to draw sketch maps of their immediate neighborhood. At this point in the book, it shouldn’t surprise you to know that these sketch maps were often wildly wrong and seldom represented distance and angle with anything like metric accuracy. Our minds simply do not map large-scale space in this way. What the findings did show was that when the sketch maps were subjected to the same space syntax analyses as the real places they were supposed to represent, there were remarkable affinities between the two. Though our mental maps may resemble real spaces only in a weak sense, they share the same syntax as physical space in the manner prescribed by Hillier’s approach. Just as space syntax analysis collapses much of the metric size and shape of space to a series of nodes and lines, so does our mind put maps of space together as a series of simple viewpoints (the nodes) and the connections between them (the lines).14

  Like isovist analysis, one of the most remarkable features of these studies is the finding that the reasons for our movements through a space are much less important than the bare structure of the space—the way that different areas in a space are enclosed and connected. Though knowing the functional organization of a space (where the stores are, where the washrooms are, and so on) can enhance our ability to predict movements through that space, the organization of the space is a much stronger predictor of our movements than what kinds of functions are served by the space. It might seem a little odd for me to tell you that when you jump in your car and drive into the city, or hop off the bus and start walking the streets of the urban core, I can predict exactly where you will go based on how the streets are connected together without needing to know that you have set out to, for instance, buy a pair of shoes. To make sense of this claim, remember that Hillier’s theory is really meant to account for aggregate behavior of large numbers of people in cities. Though the computer that calculates the integration values of streets in your city couldn’t possibly realize that you need new shoes, when many such trips to the city for many purposes are averaged together, the computer can do a pretty good job of predicting how such trips will be organized.

  There’s another way of thinking about the relationship between the shapes and connections of city spaces and the kinds of attractions that might be found in particular places. Imagine that you are an entrepreneur and you want to establish a retail business in a city. How do you look for a site? It doesn’t take a roomful of psychologists or planners to tell you that you want to place your business in an area with lots of foot traffic, and it may be that the best way to find such a site is to use the time-honored methods of William Whyte—go and watch what happens on the street. In other words, it’s probably no accident that successful businesses that depend on walk-in traffic are located in areas with high integration values. What is new and more interesting is that space syntax methods give us a way of predicting where such integration values will be found before we go looking, or even before the streets are built. These methods work so well because they mirror the ways that our mind responds to the properties of space, thus making a direct route from the way our mind works to the shapes of our cities. Our cities succeed or fail depending on how well we understand and manage this deep connection between mind and metropolis.

  THE PSYCHOLOGY OF SPATIAL INTEGRATION

  It may seem strange at first that space syntax takes little account of the distances between locations in a city. In our busy lives, we tend to find the shortest route from one place to another, especially as our familiarity with a city increases. Yet in Hillier’s space syntax, it is only the number of changes in direction that determines the spatial integration of a location. Because Hillier’s methods are designed to predict where people will congregate rather than to explain the wayfinding performance of individuals on single trips, the absence of distance measures in space syntax is not at all problematic in this respect. More surprising, though, is that in spite of our best efforts to plot efficient courses through the city, we are often fooled about distance in ways that are exactly consistent with the space syntax approach.

  Many studies have shown that people who are led along walking or driving routes that have many changes of direction are likely to overestimate the distance that they have traveled.15 Even though we are heavily invested in finding shortcuts, our spatial mind mirrors the nodes and lines of Hillier’s spaces to such a degree that we confuse the dimensions of space in much the way that space syntax predicts. Just as we’ve seen on many occasions now, the rules of mental space often appear to be topological rather than metric, and so they are well reflected by descriptions of physical spaces based on topology.

  Just as there is evidence that we have an intuition for the configuration of space given by isovists (one piece of evidence being our facility with finding locations of prospect and refuge in new spaces), there are also signs that we have a deep latent sense for areas of high integration in more complex spatial configurations.

  Imagine that you’ve landed in an unknown city. You don’t speak the language or understand the signs, and must rely only on your inner navigational senses to find your way from place to place. Over time, your movements are likely to spread slowly from a home base (perhaps your hotel) to other areas of interest—the place with good coffee, the best sidewalk bench for people watching, the nearest Internet café for catching up with the news. Often what happens is that you learn the configuration of a major street first, and then slowly learn to find your bearings from this major street to a growing set of goal locations. It is as if the major street becomes a kind of backbone upon which you build a more extensive skeleton of routes. What makes this strategy so effective is that the major street is likely to be a location of high integration, well connected and intelligible. As long as you can find your way back to this street from a variety of locations, your risk of becoming unfathomably lost is reduced. And because the major street is well integrated, your chances of finding it, even if you become disoriented, are high. Even if you lose your skeleton, the shape of space encourages you to rediscover it by wandering.

  Notice, as well, that it is entirely possible to use this kind of approach to navigation without having any idea how the different goals you seek in th
e course of the day might be related to one another. You might have no clue how to walk directly from the Internet café to the coffee joint, but you know that the two places are connected via your skeleton, and that is all that you need to know to navigate from one to the other with ease. It isn’t that the skeleton helps you to know the spatial relationship between the coffee joint and the café.

  This relationship doesn’t matter so long as you know that both places connect to the spine route. It’s as if the café and the coffee joint are in two different universes, but they’re connected somehow by the skeleton. There is a resemblance here to the findings I described in the first part of the book related to what I called the regionalization of space. We have great difficulty in drawing connections between the visible and the invisible in cities, just as we do in small sets of spaces in psychology laboratories. We learn useful tricks that can guide us from one space to another, often by using idiosyncratic links between places. There may not be anything spatially pretty or efficient about the routes we choose, but they work well most of the time.16

  Many people have had such experiences, even in fairly familiar surroundings, where they might discover that a route they have been taking for years and years (a drive to the office, a walk through a shopping mall) is neither the shortest nor the most efficient. We sometimes even seem to take great pleasure in engaging in lengthy debates about route choices. When meeting friends for dinner in a restaurant, the debate about how best to share the bill is often rivaled only by the one about the best way to get home.

  If there were deeply felt psychological principles of space at work in the organization of cities, then one prediction would be that we could discern patterns in urban streetscapes that reflected those principles. If city plans were laid out according to the whims and wiles of wandering travelers, then I imagine that this is exactly what would happen. We could look at an aerial photograph of a city and read off the inner workings of the minds of the beings who carved streets into the earth. As everyone knows, though, this is not how cities are built. Some cities, especially those of recent vintage in the New World (Washington, D.C., for example), were planned from scratch.

  One of my favorite examples of a planned city is Canberra, the capital of Australia. Canberra’s design was the result of a winning entry in an architectural contest. Walter Burley Griffin, an American architect, couldn’t believe his luck when he was informed that his design, hurried together while on his honeymoon in 1911, had been selected and that he would have a chance to build a city from the ground up. As shown in Figure 13, the organization of the city is almost crystalline in impression, with a long central axis linking perfect sightlines of a war memorial and the parliament buildings. The street plan is filled with radial symmetry, and the center is cut through with a large artificial lake whose original plan called for tight geometric lines but was modified to provide some welcome relief to the mind by including flowing, organic shorelines.

  Figure 13: The planned city of Canberra, easy to navigate but lacking in character

  Canberra is a city of stark, geometric beauty with such perfect visual alignment that one’s breath quickens in response to the sheer audacity of the design, but my own impression when I visited was that there was something sterile and slightly artificial about the space. I felt myself to be a visitor in a giant urban museum piece rather than in the living, breathing crucible of life that we normally expect to find in a city. My occasion for visiting was to deal with some minor administrative matters at an embassy, and I couldn’t help feeling that the form of the city was perfectly in accord with my business there. I negotiated the wide, empty streets in my rental car with little difficulty, found the office I was looking for without delay, and, once my business was completed, I found few reasons to linger.

  When cities build slowly, over thousands of years, some interesting commonalities emerge that show urban spaces as reflecting pools for the shape of the human mind. Hillier’s group has noticed that most cities grow in similar ways, taking on a shape that they describe as a “deformed wheel” in which the central core of the city is connected to the periphery by a series of spokes with high integration values. This pattern is easily visible in London, Rome, and Tokyo and, with a bit of scrutiny, can be found in almost all city maps. Figures 14 and 15 show the deformed wheel organization of London and Tokyo, with shading indicating the depth of integration of individual streets.

  Figure 14: London’s density forms the hub of a “deformed wheel”

  Figure 15: Tokyo shows the same type of “deformed wheel” shape as London

  Not only is this growth pattern the best way to promote continued contact between the central core and the periphery as the city increases in size, but it also makes large cities more intelligible to support good wayfinding. Hillier argues that this deformed wheel organization is driven in part by economic forces that favor minimizing distances between markets and buyers, and in part by the organization of our minds, especially the premium that is placed on viewpoints and vistas. Hillier contrasts his approach to understanding how cities grow with older methods based on concepts of mass and gravitational attraction. Such schemes suggest that places in cities are arranged in accordance with a system of attractive forces between individuals, groups, and institutions. Large institutions or social groups within a city space attract individuals as surely as the asteroid belt orbits the sun. In contrast, Hillier’s space syntax approach is “light based rather than mass based … reflect[ing] the world we see rather than the world of distance and mass.” In Hillier’s scheme, it is not the unseen social forces of human networks of power that drive people through a space, but what attracts the eye.17

  SPACE, CULTURE, AND TRAFFIC

  Though most cities that have grown through gradual organic processes rather than through top-down planning show Hillier’s spoke-and-wheel organization, it is obvious that there are enormous individual differences between cities, many of which are related to culture. One of the joys of world travel for me has always been the jarring confrontations with city plans that don’t conform to the North American linear grid that I’ve grown up with.

  On a recent visit to Beijing, I set out one morning to find a small museum. When I arrived at what I thought was the right address, I entered the building and began to look for exhibits. I encountered an elderly woman standing before an open fire stirring a pot. I tried to speak to her in Mandarin sounded out from a phrase book, but to no avail. My mouth became dry and I began to sweat. Without the ability to communicate verbally, I looked around for spatial clues as to the nature of the room that I stood in and the building that enclosed it.

  The relationships of open and closed spaces resembled little that I had seen before. I had no spatial cultural reference. It took considerable effort for me to understand that I had stumbled into a private residence and not a museum. This is a small example of a general truth. When we embed ourselves in foreign cultures, the strangeness of how built space is used is just as disorienting as an inability to understand the local language. In Beijing, there were times when it was difficult for me to distinguish residence from business, or even residence from sidewalk—some dwellings appeared to consist of nothing more than a cloth awning stretched out over a sidewalk or even a roadway, with a cooking pot over an open fire constituting a kitchen, and some rolled blankets arranged around the outside of the canopy serving as bedrooms. Variations in spatial culture are not always so extreme, but they are persistent and often easy to spot.

  Hillier has used the city of Nicosia in Cyprus as an example of the influence of culture on space. Like many cities, Nicosia contains separate ethnic enclaves. The Greek settlement has a rough linear grid of streets with high integration that would not look out of place in North America. The Turkish settlement, with low integration, short streets, and low intelligibility, is typical of many Muslim town plans.18 Such plans are meant to steer visitors toward a few well-specified public areas and away from residential areas, and generally to
encourage privacy and to discourage co-presence. These differences show that there is an interaction between our cognition of space, the manner in which the arrangement of space sculpts our movements and our behavior, and the requirements of a particular culture. All human beings are affected by the organization of space in similar ways, and we can use this generalization about our minds to organize our movements in ways coherent with cultural values. Skilled architects and designers can bring people together or keep them apart with the same precision that a skilled potter employs to make a jug designed to mete out single drops of precious oil.

  As cities grow, one of the main constraints acting on their form is the ease with which residents can get from one place to another. The deformed wheel suggests that one way to promote such ease is through artful design of the meshwork of streets, but in modern times this can take us only so far. As urban populations have increased to staggering numbers, we have found it necessary to seek ways to conquer space by cheating time. We have learned to move more quickly.

  There can be no doubt that the advent of the internal combustion engine has had more impact on the shapes of our cities than any other single development in the last thousand years. The rules of spatial cognition don’t change—indeed, space syntax studies have shown that we can predict the movements of cars with the same precision that we can foresee the movements of people. The same tools that help us to improve the Tate Gallery or fill a public square with pedestrians can also predict how cars will move in urban street plans. But cars change the scale of cities dramatically. One rule of thumb among urban planners is that people will walk when their goals are located less than a five-minute stroll from their houses. Though the exact number or distance (sometimes referred to as a walkshed) may be a subject of debate, and may vary depending on the demographics and motivations of the walkers, one thing is abundantly clear: a driveshed is much larger than a walkshed. This is not only because cars move much more quickly than pedestrians but also because driving is almost effortless compared with walking. Provided that it is easy for us to climb into a car, and provided that the layout of streets makes it practicable for us to get around at a reasonable speed, we are willing to tolerate vastly exaggerated distances between our homes, our places of employment, and the locations of services and stores that contribute to our happy lives. Although rapid transport using both private cars and public transportation systems has made it possible to accommodate huge numbers of people in urban settings (worldwide, there are more than 300 cities with populations exceeding one million people and a handful of cities with populations in excess of 10 million), it has transformed the nature of the city and given rise to a plethora of difficult problems, many seemingly without any reasonable solution.