Your Friends & Their Friends Affect Everything in Your Life

Number 142

Did you notice recent headlines announcing that obesity is contagious? Several studies suggest that you are more likely to gain weight if you hang out with fat people. The importance of social connections in the spread of obesity is just one of the topics being examined by the new science of human networks.

Two scientists explore some of the fascinating findings about social networks in “Connected – How Your Friends’ Friends’ Friends Affect Everything You Feel, Think and Do.” Authors Nicholas Christakis and James Fowler make a convincing case that, like schools of fish changing direction in unison, we are unconsciously led by the people around us. Here are some of their conclusions:

• Our networks shape us. We all belong to social networks that have properties and functions not actively controlled by the people within them. These networks give rise to cultures that are more complicated than the participants realize, and develop much like a cake that becomes something greater than the sum of its ingredients. Humans are “ultrasocial” and our brains are deeply influenced by the networks to which we belong.
• Our networks are smart. Social networks can manifest an intelligence that augments or complements individual intelligence, the way an ant colony can act smarter than the smartest single ant.
• Happiness is contagious to three degrees of separation. Our emotions and behaviors are greatly influenced by the emotions and behaviors of those in our networks. You are influenced not only by your close contacts, but also by your contacts’ contacts, and their contacts, as well. For example, the authors found that a person is about 15 percent more likely to be happy if a directly connected person (i.e. a person at one degree of separation) is happy. But happiness continues to spread, like ripples in a pond. The happiness effect for people at two degrees of separation (the friend of a friend) is 10 percent, and for people at three degrees (the friend of a friend of a friend) is 6 percent.
• Our networks can support change. We might be more effective in tackling social issues, like crime or public health, by addressing groups of people, and not just individuals. For example, to help people quit smoking or lose weight perhaps we need to involve their families, friends and even their friends’ friends.
• Your actions matter. The authors say, “the surprising power of social networks is not just the effect others have on us. It is also the effect we have on others…The ubiquity of human connection means that each of us has a much bigger impact on others than we can see.”