Over the summer, I read a book titled Connected: How Your Friends’ Friends’ Friends Affect Everything You Feel, Think, and Do. Ever since I read it, I have been thinking of social networks in a whole new light. So this week, I wanted to write about one of the chapters in the book.
First, let’s quickly go over what a “social network” is in this context. I am not talking about Facebook or Twitter. A social network is your group of friends, and their friends, and their friends’ friends, and so on. How distant in your social network someone is from you is considered his or her “degrees of separation.” Your friends are considered one degree of separation from you. Your friend’s friend (someone that you do not know) is two degrees of separation from you. Your friends’ friends’ friends are three degrees of separation from you. This can continue out all the way out to six degrees of separation. Some of you might be thinking, I once heard that everyone in the world is connected within six degrees of separation from each other. This theory was cultivated from a clever study done some time ago, but this is not the focus of this post. *
What I am talking about today is what Christakis & Fowler (2009) call three degrees of influence. In other words, our friends’ friends’ friends can have an effect on how we think, behave, and feel. It is well established people can “catch emotions” from those around them. When college freshmen are randomly assigned to live with a mildly depressed roommate, they also become increasingly depressed throughout the first semester. If your waiter smiles during your dining experience, you are more likely to leave feeling satisfied, and also give a bigger tip. But can someone you have never met effect how you feel?
Amazingly, they can. In studies of large social networks, a person is 15% more likely to be happy if someone one degree of separation apart is happy, 10% more likely two degrees of separation away, and 6% more likely for three degrees of separation. Further, for each happy friend someone has, this increases their likelihood of being happy by about 9%. These effects are not significant after four degrees of separation.
Location within a social network has also been shown to predict happiness. When people are central in a social network, this means that they have more friends, and their friends also have more friends. When someone is peripheral, they do not have a large number of friends, and neither do their friends. When looking at the picture to the right, the dots in the middle of the cluster are considered central, and those on the outside are peripheral. In their analyses, they found that individuals who are centrally located in a social network have higher levels of happiness. So, the happier your friends are, and the more happy friends your friends have, the happier you are.
But wait, does being happy just mean that you attract more friends? When performing a very complicated set of analyses, they found that this was not the case. Over time, happy people’s networks did not expand (they did not become more central). Instead, they found that happiness spread throughout the network. When an individual became happy, so did people one, two, and three degrees away from them.
This is pretty fascinating, but why is it important? First, these effects are not found just for happiness. Throughout the book, the authors detail the same effects for depression, loneliness, obesity, health behaviors, voting, political beliefs, and more. Further, this is a potentially exciting avenue for public health interventions. Let’s say we want to improve health behaviors in a community. What would be an efficacious strategy to provide interventions to a small amount of people (which is cost effective), while also having effects throughout the community? You guessed it, target individuals who are central in the social networks.
One last thing to remember that I think is really important. While the focus of this post is that others can effect how we feel, we can also have a profound effect on others. So the next time you come across a stranger, give them a smile. You never know what that smile can do, not just for them, but others too!
*If you would like to learn more about this, please feel free to message us.
Christakis, N. A., & Fowler, J. H. (2009). Connected: How your friends’ friends’ friends affect everything you feel, think, and do. New York, NY: Back Bay Books.