#9: Structuring a social network

Social relationships can be complex systems, reaching their full potential when they are designed like a collection of elements that, in sum, are greater than their parts.

It’s helpful to think of social relationships like a redundant decentralized network, without a central hub. Instead of one, or a few individuals, at the center, acting like the central node through which information must flow, communication overlaps and can result in transformational output.

A social network with a central hub looks like this:

This structure resembles a tree; with one central node, it feels very command and control. More layers, or branches, can be added, but if the branches don’t overlap, and if one individual is in the center, communication will be inefficient and the center node will always miss some information.

Instead, a social network that is decentralized and redundant, takes on the structure of a semi-lattice, like in the diagram below.

Design social networks in a semi-lattice structure

A semi-lattice is a mathematical structure that contains a set of elements that work together to form a system, where the sum of the elements is greater than its parts. In the diagram from above, if Jessica, Omar, Dinah, Sarah, and David, overlap with each other, sharing elements, the bonds between all of the friends are stronger. For example, Dinah may tell Sarah some information that Sarah then relays to David, and then David relays to Jessica. Coming back full circle, when Jessica later talks to Dinah, Jessica is able to package up the information that she heard in a new way, resulting in valuable insight to share with Dinah. Semilattices are an optimal structure to trees.

Urban planners approach city design in this way too. In 1960, Kenzo Tenge, a Japanese architect proposed a city plan for Tokyo that is a semi-lattice structure. His plan beautifully lays out this structure through a series of loops stretched out across the Tokyo Bay.

There are four loops that contain three medium loops. In the second loop, there is one medium loop for the railway station and one for the port. Each medium loops contains three minor loops that are residential neighborhoods, except the third loop that has government and industrial offices.

Contrast the Tokyo Plan of 1960 to the County of London plan of 1943.

The London Plan was proposed to the city council by architects, Abercrombie and Forshaw, in 1943. It is comprised of large numbers of communities, each separated from all adjacent communities, to emphasize the identity of individual communities. The structure is a tree, not a semi-lattice, and could cause unfortunate behaviors like segregation, fragmented information flow, and barriers to idea flow.

Density, not size, is key for a thriving social network

As architect and design theorist Christopher Alexander writes in his 1961 essay, A City is Not a Tree:

The semi-lattice is the structure of living things, of great paintings and symphonies.


In a natural city, play takes place in a thousand places, not in just 1 fenced enclosure of a playground.

The magic of a social network is not in the quantify of elements, but rather in the density of the relationships between elements. Social relationships are meaningful and thrive when they are dense and when they’re full of people who know each other and also know you.

As the line between real-world and virtual communities continues to blur, it presents an opportunity to meet more diverse people and create connections that span virtual communities, eventually cross pollinating and overlapping, forming meaningful output that is greater than the sum of its parts.


A City is Not a Tree, Christopher Alexander

On Social Support Networks, Katerina Bohle Carbonell

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