The Contagious Spread of Behaviors Through Social Networks

Summary

In this article, we explore the research of physician and social scientist Nicholas Christakis on the way social behaviors spread contagiously among people. Christakis and his collaborator, James Fowler, used data from the Framingham Heart Study to create a network of people and study how behaviors spread among them. They discovered that behaviors can spread beyond just pairs of individuals and up to three degrees of separation within a network. This has health implications, such as the difficulty in getting people to stop smoking.

The Widower Effect and the Spread of Behaviors
The Human Superorganism and Social Networks
The Three Degrees of Influence Rule
Health Implications of the Three Degrees of Influence Rule
Clusters of Individuals Changing Behavior

The Widower Effect and the Spread of Behaviors

Nicholas Christakis became interested in studying the way social behaviors spread contagiously among people while working as a hospice doctor. He discovered that the widower effect, where one partner’s death increases the risk of the other partner’s death, is a special case of a broader phenomenon where all kinds of behaviors can spread beyond just pairs of individuals. Christakis and Fowler studied a diverse set of human behaviors, including weight gain, exercise, and emotions, and were interested in understanding how they could spread beyond dyads.

The Human Superorganism and Social Networks

Christakis and Fowler used data from the Framingham Heart Study, a famous epidemiological study that has been going on since 1948, to create a network of people and study how behaviors spread among them. They observed that social networks function like a human superorganism, where individuals are like cells in a body. The structure of social networks is important, and certain individuals, such as those with many connections, are more important for the spread of behaviors.

The Three Degrees of Influence Rule

Christakis and Fowler observed a three degrees of influence rule, where certain behaviors can spread up to three degrees of separation within a network. This means that a person’s behavior can influence not only their immediate connections, but also their connections’ connections, and their connections’ connections’ connections. This has implications for the spread of behaviors, such as the difficulty in getting people to stop smoking.

Health Implications of the Three Degrees of Influence Rule

The three degrees of influence rule has health implications, as certain behaviors, such as smoking, can spread through networks up to three degrees of separation before dissipating. Research suggests that smokers tend to be clustered in networks that are not connected to non-smokers, which may explain why smoking rates have plateaued. This observation highlights the difficulty in getting people to change their behavior, as it is not just a matter of convincing individuals, but also their connections.

Clusters of Individuals Changing Behavior

Christakis provides an analogy of a wedding banquet to illustrate how clusters of individuals can change their behavior simultaneously. If a group of people at a wedding banquet suddenly gets up to dance, it can influence others to join in, creating a chain reaction of behavior change. This illustrates how clusters of individuals can change their behavior simultaneously and how social networks can influence the spread of behaviors.

Conclusion

In conclusion, Nicholas Christakis’ research on the contagious spread of behaviors through social networks has important implications for understanding how behaviors spread and how to promote behavior change. The three degrees of influence rule highlights the importance of considering not just individuals, but also their connections, when trying to promote behavior change. Understanding the structure of social networks and how clusters of individuals can change their behavior simultaneously can also be useful for promoting behavior change.