Connected: How A Social Network Works in Everything From STD’s to Friendship

When I purchased this book I read the title and subtitle and figured it was just about Twitter and Facebook and those type of social networks. While they certainly appear, Connected, by Nicholas A. Cristakis and James H. Fowler, is not a book solely about technology. It’s a book about the relationships around us and how those connections work.

This book focuses on our ties to others and how they affect emotions, sex, health, politics, money, evolution and technology. But most of all it is about what makes us uniquely human. To know who we are, we must understand how we are connected.

While there is a fair bit of repetition in the book, the authors are using some basic principles throughout each chapter. They use the chapters to show you how these basic principles apply to different networks. They cover politics, your influence on those around you, how those around you influence you, and a number of other fields.

Let’s start by defining some of the core findings and terms before we dive into what they mean in the different areas covered by the authors.

You can find an audio version of this post here: Should I Read It 012 – Connected. Make sure you don’t miss an episode of Should I Read It by subscribing

The Core Concepts Threaded in Connection

The first concept we need to cover is the two fundamental aspects of any social network, connection and contagion.

First, there is connection, which has to do with who is connected to whom.

This is your relationship with those around you. Not just your family, but any relationship, including the one with your barista. But a network not just a collection of people, according to the authors it must contain one more thing to be a network. It must contain connection.

While a network, like a group, is a collection of people, it includes something more: a specific set of connections between people in the group. These ties, and the particular pattern of these ties, are often more important than the individual people themselves. They allow groups to do things that a disconnected collection of individuals cannot. The ties explain why the whole is greater than the sum of its parts. And the specific pattern of the ties is crucial to understanding how networks function.

Most of the rest of the book examines how our connections and our place in the network affects us and those around us. Are we loosely connected on the outside of a network? Then we might commit suicide and detach from the network, but we might infect (see contagion in a second) others we had connection to, with suicide and spread it. As we left the network we made those few we were connected to that were also on the fringe less connected. They’re now more on the fringe of the network.

Second, there is contagion, which pertains to what, if anything, flow across the ties.

Many things can flow across the ties you have. It can be good or bad, from love to STD’s. They all work quite similar, as we find out as we keep reading Connection.

One example they use to illustrate contagion is a bucket brigade. We could run back and forth along a path to bring water to a fire, but that is very inefficient. The bucket brigade passes buckets along (this is what flows) and thus it can move much more water to the end with much less effort from the group as a whole.

Murder can also be a contagion just like suicide which we’ve already referenced.

It can spread either in a directed fashion (retaliating against the perpetrators) or in a generalized fashion (harming nondisputants nearby). Either way, however, a single murder can set off a cascade of killings. Acts of aggression typically diffuse outward from a starting point — like a bar fight when one man swings at another who ducks, resulting in a third man getting hit, and soon (in what has become a cliche precisely because it evokes deep-seated notions of unleashed aggression) punches are flying everywhere.

To be on a proper footing to understand connection and contagion, we need to have at least a cursory grasp of the rules of contagion and connection.

Rule 1: We Shape Our Network

We make decisions about who we connect with, and we usually connect with people that are similar to us. We also decide how many people we connect with and how we connect with them. We can choose put ourselves on the outside of a network.

Rule 2: Our Networks Shape Us

As much as we shape our networks, they shape us. If we are loosely connected, having few friends, then we are shaped by that. In fact we learn later that it’s quite possible for us to continue to drift further away as we have no friends because we may suffer depression and thus cut off the contacts we have already.

Having lots of friends also shapes us, in that it can make it much easier to make key connections we need because we have friends of friends of friends that we can reach. This is the three degree rule, which we’ll explain in a bit.

Rule 3: Our Friends Affect Us

This may seem obvious, but our friends affect us. If we sit beside a friend, or anyone that eats a lot, we are more like to eat a lot. If a friend quits smoking, we are more likely to quit.

So, if you want to get in shape, start building friendships with people that are in shape already or working towards fitness.

Rule 4: Our Friends’ Friends’ Friends Affect Us

Our friends’ friends’ friends also affect us. If that far away connection, that we may not even know, gains weight we are more likely to gain weight. If we are connected to them through many friends, then we are even more likely to gain weight as well.

Our own research has shown that the spread of influence in social networks obeys what we call the Three Degrees or Influence Rule. Everything we do or say tends to ripple through our network, having an impact on our friends (one degree), our friends’ friends (two degrees), and even our friends’ friends’ friends (three degrees). Our influence gradually dissipates and ceases to have a noticeable affect on people beyond the social frontier that lies at three degrees of separation.

This tendency of things to spread along connection lines is called hyperdyadic spread.

Another term that is used in the book and relates specifically to the Three Degrees of Influence Rule is the idea that relationships are transitive. If you look it up, the definitions have symbols and variables in them. Just think of it as a triangle.

A transitive relationship is 3 things that are related on at least one edge, so they form that triangle. That’s you and two friends that hang out with each other, but not as a group. At least you don’t have to hang out as a group.

In my life it’s like my friend where we regularly have dinner and go hiking. I also work out with her running coach at CrossFit but the three of us don’t hang out all together. That’s a transitive relationship.

Rule 5: The Network Has a Life of its Own

The final rule is that some things in a network can only be understood by studying the network as a whole. You can’t understand what’s going on if you only study a single person, or just a few people. You must model the whole network to see what’s going on.

While it’s not officially part of this rule, networks also tend to magnify what is fed into them.

Social networks, it turns out, tend to magnify whatever they are seeded with.

This also brings the famous quote to mind: “You are the sum of the five people you hang out with most”. Knowing of the Three Degree rule, it can be extended to say that you’re also the product of the friends their friends have. What those friends of friends are feeding into the network is what will get amplified.

You’ll be amplifying it so make sure it’s stuff you want to amplify.

Emotions are non-specific but fast

We have two main methods of communicating. Language and emotions. Emotions show themselves with our body language. A single glance can transmit so much good or bad.

What emotions lack in specificity compared to oral language, they make up for in speed. You can tell whether your spouse is mad at you very quickly, but having her explain it to you may take a good deal more time.

While I don’t like the subtle jab that it must be a female that will take a while to express her feelings verbally, but will quickly give you the cold shoulder, it does a decent job of helping you feel what goes on. The speed at which we instantly feel what others are feeling also helps explain how feelings act as contagions in groups.

The whole group can feel the tension of a situation and without any type of verbal communication respond to it, for good or for ill.

You only care that you’re doing better than others

It seems insane to me, but most people would rather make $30k a year knowing everyone else around them makes $28k than make $36k with others making $38k.

People assess how well they are doing not so much by how much money they make or how much stuff they consume but, rather, by how much they make and consume compared to other people they know.

Dave Ramsey, the financial guru, has a quote to show this insanity for what it is. I goes something like: “You purchase things you don’t want with money you don’t have to impress people you don’t even like.”

We’ll see this a few times in the book. We almost always gauge our success based off how we think others are doing. If they have a bigger house, we are dissatisfied with our house.

Dunbar’s Numbers

The final big concept you should understand is Dunbar’s numbers. While they aren’t specifically introduced until much later in the book, once you know what Dunbar’s numbers are you’ll see them throughout much of the material in Connected.

Here is a definition from Wikipedia:

Dunbar’s number is a suggested cognitive limit to the number of people with whom one can maintain stable social relationships—relationships in which an individual knows who each person is and how each person relates to every other person.

Dunbar actually had three numbers for our groups.

  • 38 “overnight camp”
  • 148 “band or village”
  • 1155 tribe

They key one that we see around is the 148 number for the band or village and it’s usually rounded to 150. Recently we’ve even seen research that tells us our new and fancy social networks don’t break this number. Even in Facebook we have about 150 real friends. That’s people we can keep track of our connection with.

There has been much greater variability in size found with the overnight camp and tribe numbers, and they are much less cited. Most times when someone is citing Dunbar, they are only really talking about the 150 band or village number.

With those key concepts under your belt, you’re ready to dive into the rest of Connected where the authors are going to show you how the key concepts work throughout life.

When you smile, the world smiles with you

We may think that how we feel is our own thing. We control it. We are a black box and it’s up to us what goes on inside.

Nope, that’s a lie. Reference the Three Degree Rule, how we feel is greatly influenced by those around us. Wait staff at a restaurant can get a better tip from you if they smile at you.

Now that doesn’t mean that if we are a 4 out of 10 on the happiness scale, we can become a 7. We tend to have a fixed state for our long term disposition.

…each of us tends to stay put in a particular long-term disposition; we appear to have a set point for personal happiness that is not easy to change. In fact, like other personality traits, personal happiness appears to be strongly influenced by our genes.

This fixed position over the long term is the hedonic treadmill in action. Sure it felt like you had so so much money at first when you got a raise, but 6 months in it was just the normal income. You adjusted your expectations to the new level of income.

You have less choice about your partner than you think

Because we are so sure of our individual power to make decisions, we lose sight of the extraordinary degree to which our choice of a partner is determined by our surroundings and, in particular, by our social network.

I met my wife at camp. I went to camp because I went to a college that was run by the same parent organization as the camp. I went to the college because my chiropractor told me I’d probably like it and then wrote me a reference letter. I met my chiropractor at church.

Unsurprisingly my wife was also a church person in the same denomination. Many of our core beliefs are very similar, which shouldn’t surprise anyone.

We mostly marry people that are like us, even as we marry more and more across racial lines. While people increasingly meet their partner online, family is still much more likely to introduce you to your partner.

If you’re in the centre of a network, better connected then you have more choice of partners.

Bigger and broader social networks yield more options for partners, facilitate the flow of information about suitable partners via friends of friends, and provide for easier (more efficient, more accurate) searching. Hence, they field “better” partners or spouses in the end.

The authors also talked about the benefits of marriage to both partners in a traditional marriage.

…being married adds seven years to a man’s life and two years to a woman’s life — better than most medical treatments.

They also talked about having your spouse die and that when this happens men die much sooner than women. They supposed that1 this was because the main benefit that a woman received was financial and that this benefit stayed around after the death of her spouse through things like insurance. The many benefit that a man received was emotional, and this is gone when their spouse dies.

The emotional support spouses provide has numerous biological and psychological benefits. Being near a familiar person — even an acquaintance, let alone a spouse — can have effects as diverse as lowering heart rate, improving immune function, and reducing depression.

Many men don’t make broad connections on a deep emotional level so they don’t have friends to turn to when their spouse dies. They loose the health benefits of marriage then. At least that’s the guess, and I’d love to see more research on this that’s more current than Connected.

As Cristakis and Fowler talked about marriage they also brought up the network affects of abstinence pledges. I’ve seen these go through churches and schools and my belief was that with more people on board, there would be better adherence to the stated ideal.

The research says that I’m wrong. The key to keeping an abstinence pledge is the special status it confers upon the person taking it. When it’s no longer special, it becomes meaningless and thus people don’t stick with it.

This hurts me as much as it hurts you

Later in the book we start to look at the less savoury things that can get passed around a network, specifically we start with STD’s.

In opposition to most networks, that look like a web of connections, most sexual networks are like a ring because of an unacknowledged rule that best friends don’t swap partners. Oh sure it happens, and many people would deny that the rule exists, but the network research shows that it does.

They looked a school with well above average incidents of STD’s and what they found was that the rule above was broken. Girls would go to parties and offer to have sex with all the boys that were there.

The more paths that connect you to other people in your network, the more susceptible you are to what flows within it.

Because many of these girls were central hubs of connection, STD’s spread throughout the entire population of the school with blazing speed.

In short, when trying to understand the spread of STD’s, how and even whether the disease spreads depends on the larger patterns of contact in the overall network. Without information on individuals’ partners’ partners and their interconnectedness to other individuals in the population, we cannot determine whether a person is at high risk or low risk of contracting an STD. In fact, the situation is even more complex since ideally, in addition to the structure of the network, they way the ties and overall network structure changes across time should also be taken into account.

The big thing that helped stop and rollback the spread of STD’s in the school was not some abstinence campaign, it was a campaign to get the rule about not swapping partners back in the mainstream thoughts of the students. This stopped the “hubs” of connection.

As Christakis and Fowler explored STD’s they also explored body image and media. While it’s a common assumption that people are heavily influenced by the images they see, this isn’t quite supported by their research.

People see images of ideal body types in the media, but they are less influenced by such images — by this ideology — than they are by the actions and the appearance of the very real people to whom they are actually connected.

You’re much more likely to be influenced by the body shapes and norms of those around you. Remember the Three Degree rule here, that your friends’ friends’ friends body image will affect your body image.

One of the final interesting points as they looked at some “bad” things and contagion was a gender difference in alcohol consumption influence. My initial assumption would have been than men drinking heavily would strongly influence those around them, it turns out that a women drinking heavily is a much stronger influence.

If a woman starts drinking heavily, both her male and her female friends are likely to follow suit. But when a man starts drinking more, he has much less effect on either his female friends or his male buddies down at the bar.

Bank runs and irrational decisions

Have you ever known something was true, and yet didn’t follow this rational decision through to it’s end. You followed the lead of someone you knew even when you knew the decision was poor? This is emotional group contagion at work.

Bank runs are classic examples of how individually rational behavior can lead to communally irrational behavior. we are all capable of thinking with our heads, but our hearts keep in touch with the crowd, and sometimes this leads us to disaster. Social networks can make a problem worse because they make it possible for the first people who panics to influence many others (like the couple who decided to withdraw their money once they discovered their friends had). The wisdom of crowds can quickly turn to folly.

You also see his affect in ratings of products. If you see a 5 star rating of something you’re more likely to give a 5 star rating.

Agile project management methods, like Extreme Programming and Scrum, try to combat this tendency with their planning poker ideas for ranking the difficultly of tasks. Everyone around the table pulls out their card with the difficulty ranking on it and places it face down. Then you all flip the cards over at once.

If you let someone go first, then you have influence the ranking of everyone else. This is double so when the first person to go has some authority over the rest of the team.

When we look at money, we also need to acknowledge the political drum that gets banged about trickle down economics. That is the idea that when you benefit people at the top of the ladder, the benefits drip their way down to people lower on the ladder.

What the research shows in Connected is that this simply isn’t true when it comes to social networks.

While elites like corporate directors clearly benefit from shaping social networks to suit their needs, it is less clear whether these benefits reach other levels of society. If anything, social networks might be seen as an explanation for why economic inequality continues to rise. The logic is simple: if you are rich, you can attract more friends, and if you have more friends, you can find more ways to become rich. And recent changes in technology might make the problem worse. When it is easier to search and navigate social networks, the positive-feedback loop between social connections and success could create a social magnifier that concentrates even more power and wealth in the hands of those who already had it.

Given that Connected was published almost 10 years ago, one would think that the drum would stop being beaten. Alas, politics is a fickle beast that doesn’t adhere to sanity much of the time.

The Whole is Great

If you were at a fair and needed to guess the weight of a huge pumpkin to win a prize few individual guesses are close to correct. But a funny thing happens when you take all the guesses and then average them, it’s almost always really really close.

Social networks can manifest a kind of intelligence that augments or complements individual intelligence, the way an ant colony is “intelligent” even if individual ants are not, or the way flocks of birds determine where to fly by combining the desires of each bird.

We see this in Wikipedia as well. It went from a thing that many teachers said should never rear it’s ugly head as a reference, to something that is updated rapidly and accurately many times a day.

Now this is a good way that the sum is better than the whole. Throughout the book Christakis and Fowler use the term “good” as a reference about what the network produces. They don’t literally mean something that is beneficial to society, they are simply reference whatever it is that is produced by the network.

It can be that the “good” produced disadvantages most others in a society.

But in an increasingly interconnected world, people with many ties may become even better connected while those with few ties may get left farther and farther behind. As a result, rewards may flow even more toward those with particular locations in social networks. This is the real digital divide.

If we want to address this stratification of society then we need to connect across race, religion, income, and any other way. It’s only with this type of forced connecting that we can start to see benefits of networks start to equalize for all. If full equalization is in fact the goal.

Just putting better books or technology in a a school doesn’t address the issue of the connections that students can make inside a school.

To address differences in education, health, or income, we must also address the personal connections of the people we are trying to help. To reduce crime, we need to optimize the kinds of connections potential criminals have—a challenging proposition since we sometimes need to detain criminals.

Any holistic solution must address the connections that can be made and allow students to make connections that increase the positive benefits that can be had.

A Few Things I Didn’t Detail

There are a few topics I didn’t cover in the review. In politics, no a single vote doesn’t matter mathematically, but if you vote your friends are more likely to vote and the Three Degree Rule exerts it’s force. If you’re marketing a political movement, you should be finding influencers that are well connected in a group and can get others out to vote. Ryan Holiday talks about this same idea in Perennial Seller, and gives you some great strategies to connect to these influencers.

Christakis and Fowler also had a whole chapter discussing the early formation of our social networks and the tension that is in every network. It’s summed up well in this quote from the book:

Do we help our friends or help ourselves? And what are the consequences? Will we look dumb if we help others? Will we look mean if we do not? Is it possible to be nice and survive? And how can we possibly make these decisions when we have many friends in a dancing pattern of shifting alliances and interests?

They hypothesize that early on those who could network better, work together, helped the group get more food. Then those genes were more likely to pass on and we became the social creatures we are today.

In a few ways Connected shows it’s age amongst all the good that is in there. The authors state with certainty that we’ll have a central place to manage our online social profiles and that we won’t have the silo’s that we currently clearly have. I wonder how they’d update that statement with the current state of social media, because it’s only going more centralized in search of a business model.

Connected wraps up with a reading guide so that you could lead a group through the material. It provides a bunch of great questions to answer amongst the group to dig deeper into the material.

Should You Read Connected?

If you want to dig deeper into the research than I could ever provide in a review, then yes you should read Connected. If this is merely an interesting topic to have some cursory knowledge about, then you’ve got most of it.

Go back and do some extra research on the core topics I highlighted at the beginning and then move on to some other reading. It’s not that Connected is a poor book in any way, it just may not be the key book that you need to read to take the next step in your life.

Purchase Connected on Amazon

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  1. And had research that at least partially supported the guess. 

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