2 October 2024
This is the fifth of a series of posts on complexity. We’ll be exploring some of the ways that studying complex systems gives us a more nuanced way of understanding the world, how this is relevant to all our lives, and the unique contributions we can make to this new way of understanding the world from Aotearoa New Zealand.
On a Thursday afternoon in June, a power pylon toppled over in a small rural area in Aotearoa New Zealand, cutting power to most of the Northland region.
This happened after contractors removed too many nuts from the bolts securing the pylon during cleaning. The seemingly mundane act of removing these nuts led to catastrophic effects: the three unsecured legs of the pylon lifted, the tower toppled off its base, and the resulting electricity outage affected 100,000 properties.
Electricity is distributed through a network, and this particular pylon was crucial to the network. The removal of the pylon had a massive impact on the transmission of power between communities.
Things spread through networks
Networks are made up of nodes and links. Electricity networks are easy to imagine, with power stations and substations the nodes, and power lines the links that connect them.
Not all networks are as visible as power grids. For example, we can think of people as nodes in social networks, and their interactions as links between them. Information, ideas and disease travel through these networks as power may flow through an electrical grid.
When we talk about “spread”, we’re looking at how something travels from one node to another across a network. Sometimes we want things to spread through networks with as little difficulty as possible, such as electricity or food. In other cases, we want to prevent things spreading through the network, like disease or extremist ideologies.
In the 21st century, understanding how things spread on networks is vital for the world to thrive. The Covid-19 pandemic made this very clear. Knowing that the virus spread through close contact with infected individuals, governments were able to make policies and give advice on the most effective way to sever networks to prevent spread. Just like that downed power pylon in Northland, removing links prevented spread on the network.
The networks that spread information fundamentally shape our experience of the world
Information is another thing that spreads on networks. This happens over many scales – from talking to your neighbour over the fence, to reading online news from the other side of the world.
Even in our digitally-connected world, information is still closely related to geography. We still prefer to interact with people who share our worldview, which in turn influences where we choose to live and work, and the kind of information that we access – nodes can often choose which links are created which, in turn, influences the nature of future links.
Companies that depend on producing and implementing new knowledge depend on these networks. It’s no accident that Silicon Valley developed around Stanford University and continues to be a hub for the high tech sector. These environments make it easy for information to spread between like-minded people and are often constructed intentionally – as in the case of science parks. In short, the dissemination of information within networks can profoundly affect the design and growth of physical spaces.
Important nodes in information networks that spread information between communities are often referred to as `brokers’ or `structural holes’. These brokers are an important part of how societies reach consensus. One example of brokerage in the context of information spreading is how iwi and other communities are represented in governmental bodies through elected representatives. These people act as bridges between communities and the broader political system, facilitating the flow of information between them. They relay the community’s concerns to the government and bring back key updates, ensuring both sides stay informed and engaged.
The structure of networks affects how things spread
The structure of the network, including how densely connected it is and whether it contains distinct groups or isolated nodes, plays a crucial role in how quickly and widely information spreads. Communities within the network may facilitate rapid sharing within their group but slow the flow to others. Additionally, the strength and frequency of connections between nodes can impact the speed of diffusion – strong, frequent interactions often lead to faster spread, while weak or sporadic ties may slow it down.
Different things can simultaneously spread across a network. This was highlighted during Covid-19 as the spread of disease and information between people interacted in complex ways – such as misinformation influencing behaviour – with tangible effects on the health of people across the world.
Food and values spread like electricity
Thinking in networks shows how different phenomena, both tangible and abstract, spread in remarkably similar ways. The simple example of electricity supply failing due to a fallen pylon can give us insight into seemingly unrelated things, like the distribution of food – or values and beliefs.
The food that we depend on for survival is distributed through a network. This was made starkly clear by the disruption of Covid-19, which restricted the flow of food between food producers and household consumers. Food producers, retailers and restaurants – or, nodes in the network – were affected by unwell workers working at reduced capacity, or closed as non-essential businesses, and the links between these nodes were disrupted.
However, while the usual regular food supply chains were constrained, local communities self-organised to decentralise the network. Alternative food networks were established to get food to people who needed it, through informal and voluntary efforts by communities. That is, new links sprung up organically and at a more local scale to compensate for disruption at the national scale. Communities saw the value in these emergent experiments, which has meant that some of these novel and innovative networks have persisted. This new coexistence of food distribution networks at distinct scales has improved the resilience of aspects of the spread of these vital, and delicious, components of our daily lives.
This example demonstrates how seemingly different things like food and values can spread through networks and interact with each other in unexpected ways. While food moves through a physical network, values hitch a ride and shape the way in which these networks form and persist—the values that led to informal food networks being set up have also helped sustain them, as their success reinforced the underlying beliefs that keep them going.
Qualitatively different but quantitatively similar
Electricity, ideas, values, food, disease – many different things spread across networks. Although they are different in character, these networks often have the same universal underlying architecture, and behave in quantitatively similar ways. This means that by studying networks, we can gain insight into the spread of seemingly very different phenomena.
If a power pylon can fall over and cut power to 100,000 properties, what does this mean for other things that spread across networks?
A collaboration between Te Pūnaha Matatini Principal Investigators Kyle Higham and Emma Sharp, and illustrator Hanna Breurkes. Edited by Jonathan Burgess.