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Need-to-Know Stuff: Social Network Theory

Need-to-Know Stuff: Social Network Theory


If you haven’t heard of Social Network Theory, here’s a primer, based on ‘Connected’ by Christakis and Fowler

Maths makes it possible to observe Social Networks and the impact that they have on the way ideas, disease, and even trends like obesity travel through society.

Nicholas Christakis and his colleague James Fowler explain in their book Connected:

If your friend’s, friend’s, friend puts on weight you are at increased risk of weight gain too….

That’s mind-blowing stuff because you can’t directly control the fact that someone you don’t even know, the friend of a friend of a friend is putting on weight, and yet their weight gain impacts on you!

Christakis explains that human Social Networks tend to have similar structures, but they do differ in how they ‘transmit’ phenomena like ideas, disease, social behaviours. Sometimes being geographically close is important to transmission (in the case of infectious disease), and sometimes not, in the case of obesity. However the rule of thumb is that networks ‘transmit’ to three degrees of separation before social decay happens, which is why your friend’s, friend’s friend’s weight gain might matter to you.

In their work, Christakis and Fowler have investigated how transmission in Social Networks happens, and have shown that it can’t be explained just because the people in the Network are similar (bigger people being friends with bigger people). Nor is the transmission explicable because all the people in the Social Network are being exposed to the same thing at the same time. The transmission of obesity is also explained by induction or the social domino effect.

In other words, simply being in a Social Network, being connected, changes our lives in ways we might not be consciously aware of, or indeed be actively choosing.

Christakis believes it’s important to recognise the significance of the Social Network as an entity in itself. Why? Because Social Networks are social structures for transmission:

Networks magnify whatever they are seeded with

It is likely that Social Networks are features of human nature as old as time.

It is also likely that our genetics pre-dispose us to where we find ourselves within a Social Network. We might be in the centre connected to lots of people who are also connected. We might be on the periphery, connected to fewer people. (Sociable vs shy).

The fact that humans vary in their connectedness is important, because the Social Network relies on people being differently connected in order meet different challenges.

Christakis gives the example of hunting for a Lion in a primitive society. Imagine you live in the primitive society and you want to find a Lion.

Imagine you want to kill the Lion. In Social Networks, most people have a number of strong connections. Maybe six friends? If you want to find the Lion it is helpful for you if your friends don’t know each other and nor do their friends’ friends. That means you have a greater pool of information coming back to you about where the Lion is…

If you want to kill the Lion, then it’s better if your friends are all friends with each other, they will act as a tighter unit that way.

So in technical terms the ‘transitivity of the node’ is important to the network. If all your friends are friends of each other, you have high transitivity going on, if you friends are not friends of each other transitivity is low.

So, why does Social Network Theory matter?

First, it’s critical to the way we think. We exist, as humans as individuals, but we also exist as a constituent part of a Social Network. We are nodes!

Social scientists, and anybody interested in how ideas, behaviours and phenomenon spread (i.e. people in business) need to understand be thinking about how social networks work and how they can be influenced, not just how individuals, or even groups work. It’s the connected nature of social networks that matter…

Being reduced in significance to a small cog in a big machine, being turned by the other cogs turning, might feel a little too humbling to many of us. it threatens our feeling of free will and agency. But go back to the friend’s friend’s friend influencing your weight gain. If you flip it, your behaviour affects them too. It’s comforting to think that being virtuous in small ways can be amplified across your social network.

Christakis has experimented with altruism too and has found proof that ‘paying it forwards’ affects people’s behaviour. So if you do something generous it is likely to seed generous behaviour in others. We copy bad habits, we copy good ones too.

Second, Christakis believes Social Networks can be influenced or changed, either by imposing change on the structure, or by changing the flow of the network. He’s working at the moment on how to propagate clean water solutions in Nigeria by using mathematical modelling to select the best people within the network (village in this case) to spread the clean water solution.

The importance of Social Networks can’t be understated. Better understanding of how networks transmit, and the ability to alter the network, could help us contain the bad (I can’t help thinking about an alternative world where Hitler was prevented from ‘seeding’ his ideas) and promote the good.

At a more base level, businesses with their new access to Big Data should be able to tap into Social Network theory to understand what their customer networks look like (if I was Tesco or Boots, that’s what I’d be trying to do with my Clubcard and Advantage Card data…), and I’d be trying to identify where and how to ‘seed’ new initiatives so they spread most effectively.

Personally, I believe Social Network theory could be the most important new thinking to hit Social Science since…Marx? I only wish I was better at maths, because ultimately it’s the Science part of Social Science that’s going to help us understand human nature via Social Network theory.

If you found this interesting I suggest you read Connected, The Amazing Power of Social Networks and How They Shape Our Lives by Nicholas Christakis MD, PhD & James Fowler, PhD


Kath Rhodes, Qual Street Owner

I love love learning and so I invest time and resources with Ambreen and Claire into exploring social psychology, neuro science, creativity and new techniques in research. Read all about it and help yourself to the ideas that will deliver your business the insight it needs

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