Social networks, which features many distant connections, or "long ties," produces large-scale changes most quickly, scientists have previously thought.
But in a new study, Damon Centola, an assistant professor at the MIT Sloan School of Management, has reached a different conclusion: Individuals are more likely to acquire new health practices while living in networks with dense clusters of connections that is, when in close contact with people they already know well.
Researchers often regard these dense clusters of connections to be redundant when it comes to spreading information; networks featuring such clusters are considered less efficient than networks with a greater proportion of long ties. But getting people to change ingrained habits, Centola found, requires the extra reinforcement that comes from those redundancies. In other words, people need to hear a new idea multiple times before making a change.
"For about 35 years, wisdom in the social sciences has been that the more long ties there are in a network, the faster a thing will spread," says Centola. "It's startling to see that this is not always the case." Centola's paper on the subject, "The Spread of Behavior in an Online Social Network Experiment," is published in the Sept. 3 issue of the journal
Science.
To see what difference the form of a social network makes, Centola ran a series of experiments using an Internet-based health community he developed. The 1,528 people in the study had anonymous online profiles and a series of health interests; they were matched with other participants sharing the same interests "health buddies," as Centola calls them in the paper. Participants received e-mail updates notifying them about the activities of their health buddies.
