The Urban Village

Or, the scaling of human interactions with city size
contacts average contacts max {{tick.text}} pop: {{hoverPop | number:0}} {{hoverName}} 0 50% {{city.hoverDegree.clustPerc | number:0}}% 20% {{city.hoverDegree.amountPerc | number:0}}% 0 50% {{city.hoverDegree.clustPerc | number:0}}% 20% {{city.hoverDegree.amountPerc | number:0}}% {{x.tickFormat(6, ',.1s')(tick)}} {{hoverDegree | number:0}} contacts

How to explore the data

Citiesare ordered by population size

People in the city are grouped according to the number of phone contacts they have.

The amount of people in the city with a certain number of contacts is displayed on the left.

The probability that two of those contacts know each other is on the right.

Graph showing data from 15 months of telecommunication in cities of Portugal. † ‡

Do you thrive within the crowds of a large metropolis or do you prefer the close community spirit of village life? Analyzing mobile communication data reveals how a person’s social network changes when moving from a small town into a big city. A team of researchers from both the MIT Senseable City Lab and the Santa Fe Institute worked with Orange Labs, British Telecom and Raschke Software Engineering to study how cities affect our social relationships.

linear (β=1) Super-linear (β=1.12) city {{tick.text}} Sum of contacts {{tick.text}} City population
Graph showing the difference between a linear scaling relation and a superlinear one. ‡

Human interaction networks can be inferred from billions of anonymized mobile phone records. This study, focusing on Portugal and the UK, reveals a fundamental pattern: our social connections scale with city size. People who live in a larger town make more calls and call a larger number of different people. The scaling of this relation is 'superlinear,’ meaning that on average, if the size of a town doubles, the sum of phone contacts in the city will more than double – in a mathematically predictable way.

city {{tick.text}} Cluster coefficient {{tick.text}} City population
The chance that two phone contacts from one person know each other is not affected by city size. ‡

Surprisingly, however, group clustering (the odds that your friends mutually know one another) does not change with city size. It seems that even in large cities we tend to build tightly knit communities, or ‘villages,’ around ourselves. There is an important difference, though: if in a real village our connections might simply be defined by proximity, in a large city we can elect a community based on any number of factors, from affinity to interest to sexual preference.

The findings of this research help elucidate the role of cities as accelerators of human interactions, and the effectiveness of urban social space in the diffusion of ideas and information. Eventually, they can help us understand a broader spectrum of social phenomena, from crime to the spread of diseases.

Video

Social networks derived from mobile phone data in Portugal.

Video: Kael Greco, MIT Senseable City Lab.

For more information, see the published paper or the preprint.
You can also download the press release and the visual material.
The project was developed as part of Ericsson’s “Signature of Humanity” project.

† In this graph outliers are not considered to better show the increase in the average number of contacts.

‡ The graph only shows data from cities in Portugal.