Reflecting ourselves in the city

What can the form of cities tell us about the structure of the brain? And what can the structure of the brain tell us about the form of cities? These are questions that I’d like to address in this talk. In summary, I believe we can learn a good deal about the interaction between the mind and the urban places in which the global majority of people now lives.

After all, the city is the largest intentional product of the human species. We’ve had them for millennia and, in them, we’ve manifested our societies, created our industries and developed our cultures. They are the product of our imaginations, the places where we take decisions – and they are the inspiration for new thought. The link, I want to suggest though, is not just contextual. It’s much deeper than that.

Slide – Masterplan

My role as an architect and urban planner is to design cities, not to probe and dissect brains in the manner of earlier speakers. But that’s not to say that I’m not professionally curious. Far from it because, when architects and urban planners think about the future – where to place new facilities like schools and hospitals, how to connect them with streets, parks and public spaces, and how to make any and all of this look beautiful – when we do any of this we are anticipating human behaviour…

Slide – Public space design

…how people will flow, where they’ll want to stop, sit, read a book or interact with friends and colleagues. And in anticipating human behaviour we’re attempting to simulate the thought processes, the decision sequences, the navigational pathways and, in general, the instincts of other human brains.

Slide – Trafalgar Square

How do we do this? After all, urbanism is a long game. When we started redesigning Trafalgar Square in 1996 we had no idea that, once the square eventually opened in 2003, people would soon be using iPhones in a radical change of human behaviour that is now…


…seeing cities installing traffic signals into the pavement on the basis that people aren’t looking up any more…


…they’re all, apparently, looking down!

As an architect you can draw the physical form of the city but you can’t anticipate every dimension of how it’ll be used by people.

Nor even how the physical form itself will inevitably be adapted over time. There is no building, no street and no public space in the world that is unchanged.

The behaviours of people change and the physical form of the city changes. And of course this is not just a problem for architects. Change is a challenge for everyone. But it’s not necessarily a problem. Technology-driven change and culture-driven change can be highly positive. Indeed change is, I suggest, necessary for the advancement of our species, challenging us to think fresh thoughts and to innovate.

What I’d therefore like to speculate on in this talk is the nature of change and the role of the city in helping the human brain to cope with it.

Let’s start with the nature of change. If we accept that the only constant is change then, for this reason, we need to anticipate that all cities will be adapted over time. Broadly speaking I’d like to suggest that these adaptions follow a pattern where some things vary less and other things much more.


Let’s first consider the physical changes. We’ll then move on to the human behaviours.

The physical city

We can draw a scale from the more permanent physical features on the left to the less permanent on the right. At the left end of it – the most permanent end – is the street network of the city. Once streets are laid down – with all the cables and pipes that run beneath and above them, and then all the buildings that line them – they are very hard to move. And very expensive. For this reason, some streets in London have been here for hundreds of years. Some, like Watling Street, for millennia.

The buildings are rather less permanent. They come and go. The good ones survive longer but an average modern building may only last a few decades.

And, during the life of any building, what happens within them changes. Land uses change. Office buildings get converted into homes; fire stations into restaurants.

The place we see most frequent change is in what I’ve called the Streetscapes: the space between buildings, where the balance between cars, bicycles and pedestrians is seemingly ever changing. Not just as a result of the utilities companies coming along and digging them up on a weekly basis, but in the trends we have seen in the last century…

Slide – Bucharest

…first, towards providing ever more space for cars and then, more recently, in the move to reduce road space and make greater provision for pedestrians and cyclists.

Slide – Cape Town

Back in 1996, Trafalgar Square was an example of government saying that the balance was wrong, and of wanting the square to be less dominated by vehicles.

Architecture and urban planning tread a line between the ends of this scale. Between permanence and ephemerality. Most things are locked in. Others are more flexible.

Slide – Paris

But it’s worth considering that changes to the streetscape will only really have an effect on mobility if the street network, once transformed, is sufficiently connected and intelligible. If all you’re doing is moving moving the kerb to create wider pavements and narrower roadways then your city has “good bones” to begin with. Consider the transformation in European cities from driving to walking. It’s worth reflecting that even in Amsterdam and Copenhagen, people haven’t always ridden bicycles in the great volumes they do today. But London, Amsterdam and Copenhagen have been able to transform through a nip here and a tuck there because they are each historic cities with highly connected networks of fine-grained streets and boulevards. In other words, they have good bones.

Slide – Plan Voisin

The challenge is when you’re dealing with modern, disconnected, low density sprawl. Removing car lanes and giving the space back to bicycles isn’t going to work nearly as well if people live miles from where they work.

In such circumstances far more radical – and expensive – change is needed.

Slide – Nur-Sultan

This is in fact the situation facing many cities worldwide, including Nur-Sultan, the capital of Kazakhstan, where we’re working on a plan to repair a city built almost entirely around the car.

So the lesson is to get it right from the beginning. In my experience there are 5 key ingredients:

– connected streets

– slow speeds

– mixed land uses

– public transport

– cycling.

How can we be more precise about this?

Slide – Spatial Accessibility

The Space Syntax research programme began here at UCL in the 1970s and has investigated the spatial layout of cities and how they’re used by people.

We’ve found that it’s possible to measure the degree to which any street segment – the length of street between two junctions – is connected to all the others in the network. We call this property “Spatial accessibility” and the algorithm that produces it calculates both the distance and the angularity on journeys between every segment and every other segment.

The hotter, redder streets are more accessible and the colder, bluer streets are less accessible.

I’d like to give a very rapid overview of six key discoveries that we’ve made using this measurement:

First, that as spatial accessibility increases then so does movement. This is actually a fundamental scientific discovery to which I can only make a passing mention.

Second, land use

Third, crime

Fourth, land value

Fifth, air quality

Sixth, health.

Slide – King’s Cross

With this knowledge we use the algorithm as a design tool in the masterplanning of new developments.

Case studies:

Slide – Trafalgar Square

Slide – Integrated Urban Model

Slide – Olympic Park

Slide – Changchun

Slide – Darwin Land Value

Slide – Melbourne global

When we look at the historic record we see certain consistencies, at least until the 20thCentury when architects went experimental. Across the urban record, across cultures and geographies – and I’m using Melbourne as my case study here – we see:

  • rectilinear grids: grid structures where streets intersect at approximately 90 degrees
  • a particular kind of spatial hierarchy: a foreground grid of main streets; the boulevard system of the city where the major commercial activities occur and a background grid of minor streets, where people live

Slide – Melbourne Local

  • we see patterns of local centrality, around which different neighbourhoods form
  • and varying street segment lengths, with shorter segments streets in the neighbourhood centres (where there’s more pedestrian activity to occupy the denser street grids) and longer ones further away.

Put these together and you have a kind of spatial DNA: the algorithm of the city hard-coded into its spatial structure.

The human city

So far I’ve described the city as a physical and spatial object. But cities are human organisms too, places in which people move and interact.

And, of course, people change as well.

The drivers of change are various:

Societal. Economic. Environmental. Technological.

These drivers bring new people to cities – for example migration in pursuit of economic opportunity – and they bring new behaviours to everyone.

All of this creates the challenge of the new. And we as a species need to be able to deal with that. So how can cities help?

The role of the city

Well, if societies are set problems by environmental change and the brilliance of continuous human invention then cities create the conditions in which those problems can be answered.

Environmentally, by mitigating the harsh effects of rainfall, wind and sun.

Societally, by bringing people together to experiment with new technologies and rapidly prototype adaptive behaviours. Thus it was with the telephone cable, the elevator, the revolving door, the tram, the car, the iPhone.

And of course cities create the conditions in which invention is most prolific because human interaction sparks human ingenuity. Cities are crucibles of invention.

There is therefore a dual process of invention and adaptation that cities encourage.

Invention doesn’t therefore just happen in the mind. It is witnessed in, inspired by and adapted in the city through physical and spatial structures that are measurable.


The city assists in the various processes that turn ideas into realities:

Copresence – sharing space with others.

Awareness – when anonymity expires.

Interaction – human to human contact.

Transaction – the processes through which people trade.

Invention – the serendipities that provoke unexpected ideas.

Application – cities afford opportunities to rapid prototype new technologies.

Reflection – it’s remarkably easy to be alone in a city.

Publication – having an audience.


The idea that I’d like to leave you with is that cities are computers. Very special computers. Generative computers with a reflective functionality.

But given the intimate connection between the human brain and the process of invention, I think it’s fair to suggest that, when we build the city we are not only building a computer: we are building the computer of our minds.

Cities are not random products of humanity. They’re purposeful. They’re there to create relationships that further the species; that form economic ties; that solve social problems; that create unplanned introductions between people that lead to unexpected conversations from which new, previously unknown ideas emerge.

I believe cities are there to interact directly with the anatomy of the brain.

Slide – grid/place cells

So when I see images of grid cells and place cells I can’t help but do two things:

  • first, compare the patterns in these images and note that we see similar patterns of centrality in cities: principally, but not exclusively, rectilinear, non-triangular shapes; triangles seem highly confusing
  • second, conject that, in creating cities we are creating extensions and enhancements of our brains. Cities are made by us to help us invent and to help us then handle the change that follows. Cities  accelerate – or replace – the otherwise insufferably slow processes of human biological evolution that will eventually enhance our cognitive capacity.

It’s an idea that I look forward to discussing with you.


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