The study is good news both for Facebook, an increasingly indispensable political tool, and for the many political campaigns now using the popular social network to connect with supporters. The study is a strong indication that online support, measured on Facebook as “likes,” and engagement, measured as the number of people “talking about” a branded page, has measurable offline consequences.

Cameron Marlow, head of data science at the social network, said at Facebook "we're excited that this research suggests that social influence and the power of friends may impact voter turnout."

The study, published in the interdisciplinary scientific journal Nature, is based on an experiment involving a nonpartisan, pro-voting Facebook post viewed by 60 million users on Election Day in Nov. 2010.

Researchers compared a group of users who saw a simple reminder to vote to a group of users who saw the same message, but associated with Facebook friends who had engaged with the message. The experimental message allowed Facebook users to click “I voted,” which then passed the message onto their friends.

The principle of social sharing is a tested campaign method on Facebook. Studies indicate that users are more likely to engage with an advertisement if it is associated with someone in their friend group.

To control for users who lied about voting — another potential consequence of online peer pressure — researchers compared voting records to users who clicked “I voted” online.

“Users who got the informational message — who didn’t see photos of friends — voted at the same rates as those who saw no message at all,” according to the UCSD press release. “Those who saw photos of friends, on the other hand, were indeed more likely to vote.”

According to lead researcher and political science professor James Fowler, the social network yielded an additional four voters for every one voter that was directly mobilized by the voting message.

“Social influence made all the difference in political mobilization,” Fowler said, according to the press release. “It’s not the ‘I Voted’ button, or the lapel sticker we’ve all seen, that gets out the vote. It’s the person attached to it.”

Facebook unveiled its own “I’m voting” application ahead of the elections this year in an effort to “make all politics social.” The application also works to mine data for analysis about users’ political opinions that is provided to CNN.

—Updated at 4:08 p.m.