You Have Three Degrees of Influence

When I was in seminary, a group of us spent some time at a homeless shelter and support service.  We were talking to the director at one point when someone asked him what he had been able to determine about the causes of homelessness from his perspective.  He said that in over twenty years of the work he had only ever been able find one commonality: everyone who ended up at the shelter lacked a support network.  They came from all backgrounds and walks of life, different races, education levels, and economic positions.  Anyone, from his perspective, might potentially become homeless.  But the ones who ended up on the street with nowhere else to turn were the ones who were alone, with no friends or family to help them when times became dire.

That's a dramatic example, but it makes the point that social networks matter.  Yet they matter in less obvious, more subtle ways just as much.  You've probably heard someone say, of sexually transmitted diseases, something along the lines of, "When you have sex with a person, you're also having sex with everyone they've ever had sex with."  Social networks are kind of like that, influence spreads from person to person to person, among even those who have never met.  Sometimes influence even skips a direct connection (the carrier) to a connection two or three degrees removed.

I first encountered research around these ideas a few years ago in an article that led to my New Year's post "I Resolve to Be a Better Influence on My Networks."  It's taken a while, but I finally got around to reading the book by the article's subjects: Connected: The Surprising Power of Our Social Networks and How They Shape Our Lives by Nicholas Christakis and James Fowler.  I found it to be a fascinating read, exploring the idea across many fields and areas by delving into a wealth of recent studies.  Here are some of the basic ideas from the introduction and conclusion; you'll have to find a copy of the book to see the nitty-gritty:

Just because we are connected to everyone else by six degrees of separation does not mean that we hold sway over all of these people at any social distance away from us.  Our own research has shown that the spread of influence in social networks obeys what we call the Three Degrees of Influence Rule.  Everything we do or say tends to ripple through our networks, 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 effect on people beyond the social frontier that lies at three degrees of separation.  Likewise, we are influenced by friends within three degrees but generally not those beyond.

The Three Degrees Rule applies to a broad range of attitudes, feelings, and behaviors, and it applies to the spread of phenomena as diverse as political views, weight gain, and happiness. . . . 

The way natural social networks are structured means that most of us are connected to thousands of people. For example, suppose you have twenty social contacts, including five friends, five coworkers, and ten family members, and each of them in turn has similar numbers of friends and family (to make things simple, let's assume they are not the same contacts as yours).  That means you are indirectly connected to four hundred people at two degrees of separation.  And your influence doesn't stop there; it goes one more step to the twenty friends and family of each of those people, yielding a total of 20 x 20 x 20 people, or eight thousand people who are three degrees removed from you. . . . 

Networks influence the spread of joy, the search for sexual partners, the maintenance of health, the functioning of markets, and the struggle for democracy.  Yet, social-network effects are not always positive. Depression, obesity, sexually transmitted diseases, financial panic, violence, and even suicide also spread.  Social networks, it turns out, tend to magnify whatever they are seeded with. . . . 

Understanding the way we are connected is an essential step in creating a more just society and in implementing public policies affecting everything from public health to the economy. . . . 

Some scholars explain collective human behavior by studying the choices and actions of individuals.  Others dispense with individuals and focus exclusively on groups formed by social class, race, or political party affiliation, each with collective identities that cause people in these groups to mysteriously and magically act in concert.  The science of social networks provides a distinct way of seeing the world because it is about individuals and groups, and about how the former actually become the latter.

. . .

The social networks that humans create are themselves public goods.  Everyone chooses their own friends, but in the process an endlessly complex social network is created, and the network can become a resource that no one person controls but that all benefit from.  From the point of view of each person in the network, there is no way to tell exactly what kind of world we inhabit, even though we help create it.  We can see our own friends, family, neighbors, and coworkers, and perhaps we know a little bit about how they are tied to each other, but how we are connected to the network beyond our immediate social horizon is usually a mystery.  Yet, as we have seen time and time again, the precise structure of the network around us and the precise nature of the things flowing through it affect us all.  We are like people on a crowded dance floor: we know that there are ten people pressed up against us, but we are not sure if we are in the middle or at the edge of the room or whether a wave or ecstasy or fear is spreading toward us. . . . 

To address social disparities, then, we must recognize that our connections matter much more than the color of our skin or the size of our wallets.  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.  To make smoking-cessation and weight-loss interventions more effective, we need to involve family, friends, and even friends of friends.  To reduce poverty, we should focus not merely on monetary transfers or even technical training; we should help the poor form new relationships with other members of society.  When we target the periphery of a network to help people reconnect, we help the whole fabric of society, not just any disadvantaged individuals at the fringe. . . . 

Embedded in social networks and influenced by others to whom we are tied, we necessarily lose some of our individuality.  Focusing on network connections lessens the importance of individuals in understanding the behaviors of groups.  In addition, networks influence many behaviors and outcomes that have moral overtones.  If showing kindness and using drugs are contagious, does this mean that we should reshape our own social networks in favor of the benevolent and the abstemious?  If we unconsciously copy the good deeds of others to whom we are connected, do we deserve credit for those deeds?  And if we adopt the bad habits or evil thoughts of others to whom we are closely or even loosely tied, do we deserve blame?  Do they?  If social networks place constraints on the information and opinions we have, how free are we to make choices?

Recognition of this loss of self-direction can be shocking.  But the surprising power of social networks is not just the effect others have on us.  It is also the effect we have on others.  You do not have to be a superstar to have this power.  All you need to do is connect.  The ubiquity of human connection means that each of us has a much bigger impact on others than we can see.  When we take better care of ourselves, so do many other people.  When we practice random acts of kindness, they can spread to dozens or even hundreds of other people.  And with each good deed, we help to sustain the very network that sustains us.