Behavior Influenced More In Denser Networks

A Web-based experiment in which an idea was planted found greater penetration and more rapid spread of the idea in a dense network of participants with overlaps compared with in a loose network. Cynthia Graber reports

Illustration of a Bohr atom model spinning around the words Science Quickly with various science and medicine related icons around the text

Join Our Community of Science Lovers!

Diseases can spread quickly. Someone with a cold infects a few casual contacts, who in turn infect others. Ideas can also spread that way, along so-called random networks. But Damon Centola at MIT says that ideas and beliefs spread faster and more efficiently when they’re reinforced in clustered networks, with overlapping connections among the members.

Centola recruited more than 1,500 participants for what was billed as a Web-based health community. Each had an anonymous profile and was matched with health buddies. In one group, a minimal number of links connected the participants. The other group was denser, with redundant links.

In each group, a seed participant was planted with an idea: to register for an online health forum. Whenever a member registered, the member’s contacts got the message. Ultimately, 54 percent of the participants in the clustered network signed up, compared with only 38 percent in the random nework. And the behavior spread about four times faster in the clustered groups. The study is in the journal Science. [http://bit.ly/96jPpc]


On supporting science journalism

If you're enjoying this article, consider supporting our award-winning journalism by subscribing. By purchasing a subscription you are helping to ensure the future of impactful stories about the discoveries and ideas shaping our world today.


Centola thinks people are more swayed when they hear that multiple contacts are trying something new and that public health officials should take advantage of clustered networks to encourage people’s healthful behaviors.

—Cynthia Graber

[The above text is an exact transcript of this podcast]

It’s Time to Stand Up for Science

If you enjoyed this article, I’d like to ask for your support. Scientific American has served as an advocate for science and industry for 180 years, and right now may be the most critical moment in that two-century history.

I’ve been a Scientific American subscriber since I was 12 years old, and it helped shape the way I look at the world. SciAm always educates and delights me, and inspires a sense of awe for our vast, beautiful universe. I hope it does that for you, too.

If you subscribe to Scientific American, you help ensure that our coverage is centered on meaningful research and discovery; that we have the resources to report on the decisions that threaten labs across the U.S.; and that we support both budding and working scientists at a time when the value of science itself too often goes unrecognized.

In return, you get essential news, captivating podcasts, brilliant infographics, can't-miss newsletters, must-watch videos, challenging games, and the science world's best writing and reporting. You can even gift someone a subscription.

There has never been a more important time for us to stand up and show why science matters. I hope you’ll support us in that mission.

Thank you,

David M. Ewalt, Editor in Chief, Scientific American

Subscribe