Is Happiness Contagious?

From Science:

Happy With a tanking economy and global violence on the rise, there's at least one thing to smile about: A pair of scientists is reporting that happiness can spread through social networks, meaning that friends of the cheery contract the happiness bug themselves. The data behind the new findings come from, of all things, a massive study of cardiovascular disease. In 1948, researchers began collecting health and other information on U.S. adults as part of the Framingham Heart Study. Today, the project has data on more than 14,000 people, and it has helped researchers identify many of the major risk factors behind heart disease and stroke. Because the Framingham leaders, trying to track volunteers over many years, worried about losing contact with them, they asked all subjects to provide the name of a friend who would know how to find them if necessary. Often, those friends were also part of the study.

Nicholas Christakis, formerly a hospice physician at Harvard, and James Fowler, a political scientist at the University of California, San Diego, used these data to create a social network of nearly 5000 people. The duo then matched the information with various health data. Last year, they reported that weight loss and weight gain could “spread” through the network, meaning that a guy whose friends were overweight was more likely to pack on the pounds himself (ScienceNOW, 25 July 2007). Christakis and Fowler published a similar finding on smoking earlier this year.

Now, the two have turned to something more ethereal: mood.

More here.