A 61-Million-Person Experiment in Social Influence and Political Mobilization

Finally, a break from annotating technical stuff. Don’t get me wrong I like it but…here’s where it hits the road: Changes in voting behavior.

viting messages displayed on FacebookHere we have a study published in 2012 in Nature on a randomized controlled study of changes in users voting behavior after seeing different versions of messages on Facebook. One group saw a message urging them to vote accompanied by profile pictures of their friends who had voted. Another group saw the same message but without pictures of their friends. A control group saw no message about voting.

The study included 61 million voting-age Facebook users, and verified changes in voting behavior by matching them with publicly available voter records. The results suggest that a single message encouraging voting, when accompanied by faces of close friends who say they voted, increased the 2010 turnout by 340,000 votes.

It turns out we are influenced by our friends. See for yourself:


Bond, Robert M., et al. “A 61-Million-Person Experiment in Social Influence and Political Mobilization.” Nature, vol. 489, no. 7415, Sept. 2012, pp. 295–98.

In a report published in Nature, the authors describe a randomized controlled study of responses to voter mobilization messages placed on the social media network Facebook on the voting day of November 2, 2010. The study targeted messages to more than 61 million Facebook users over the age of 17, and randomly assigned them to one of three groups. For the “social message group” a message was displayed at the top of their Facebook news feed urging the user to vote with a link to find their local polling place, along with a clickable “I Voted” button showing a count of Facebook users who had clicked the button, and up to six profile pictures of the user’s Facebook friends who had also clicked the button. The “information message group” was shown the same information with the exclusion of the faces of their Facebook friends. The control group received no voting message in their news feed.

The researchers were able to assess the impact of the messages by measuring three user actions: clicking on the “I Voted” button, clicking the link to the local polling place, and registering a vote in the election. They measured actual voting behavior by matching 6.3 million Facebook users to public voting records. Users in the social message group were 2.08 percent more likely to click the “I Voted” button and 0.26 percent more likely to click the local polling place link than members of the “information message” group. More importantly, examination of the voting records showed that members of the social message group were 0.39 percent more likely to actually vote than those in the information message and control groups.

The authors posit that the voting behavior of those in the social message group was influenced by strong social ties with their Facebook friends, whose faces were displayed in the message encouraging them to vote. To validate this they conducted a network analysis of “close” friends based on frequency of interaction among all Facebook friends. They found that while friends outside the “close” group had little or no effect on a user’s voting behavior, messages that included the profile picture of close friends increased the probability of the user voting. Close friends were also found to influence the users’ self-expression of voting behavior with the “I Voted” button, and in clicking the link to local polling place locations.

The study notes that while these increases in voting behaviors are small, they are the result of a single message displayed on voting day. In addition, in a voting population of 236 million people, small percentage increases add up to significantly more votes: in this case a total of more than 340,000 additional votes. Considering that in the 200 presidential election George Bush defeated Al Gore by a total of 537 votes in Florida, it becomes evident that, as the authors put it, “online political mobilization works.”