Robert M. Bond

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

Human behaviour is thought to spread through face-to-face social networks, but it is difficult to identify social influence effects in observational studies, and it is unknown whether online social networks operate in the same way–. Here we report results from a randomized controlled trial of political mobilization messages delivered to 61 million Facebook users during the 2010 US congressional elections. The results show that the messages directly influenced political self-expression, information seeking and real-world voting behaviour of millions of people. Furthermore, the messages not only influenced the users who received them but also the users’ friends, and friends of friends. The effect of social transmission on real-world voting was greater than the direct effect of the messages themselves, and nearly all the transmission occurred between ‘close friends’ who were more likely to have a face-to-face relationship. These results suggest that strong ties are instrumental for spreading both online and real-world behaviour in human social networks.

Inferring Tie Strength from Online Directed Behavior

Some social connections are stronger than others. People have not only friends, but also best friends. Social scientists have long recognized this characteristic of social connections and researchers frequently use the term tie strength to refer to this concept. We used online interaction data (specifically, Facebook interactions) to successfully identify real-world strong ties. Ground truth was established by asking users themselves to name their closest friends in real life. We found the frequency of online interaction was diagnostic of strong ties, and interaction frequency was much more useful diagnostically than were attributes of the user or the user’s friends. More private communications (messages) were not necessarily more informative than public communications (comments, wall posts, and other interactions).

The Social Origins of Adult Political Behavior

Political socialization research has focused on the role of parents, extracurricular activities, and the school curriculum during adolescence on shaping early adult political behavior (Beck & Jennings, 1982; Flanagan, Syvertsen, & Stout, 2007; Torney-Purta, Richardson, & Barber, 2004). However, no study to date has examined how properties of adolescents’ social networks affect the development of adult political outcomes. Using social network analysis, we find that both a respondent’s social integration in high school and his friends’ perceptions of their own social integration affect the respondent’s later political behavior as a young adult. Peer and network effects are at work in political socialization. This has important implications for our understanding of the development of social capital, political trust, and political participation, as well as our general understanding about how one’s social network influences one’s own attitudes and behavior.

Quantifying Social Media’s Political Space: Estimating Ideology from Publicly Revealed Preferences on Facebook

We demonstrate that social media data represent a useful resource for testing models of legislative and individual-level political behavior and attitudes. First, we develop a model to estimate the ideology of politicians and their supporters using social media data on individual citizens’ endorsements of political figures. Our measure allows us to place politicians and more than 6 million citizens who are active in social media on the same metric. We validate the ideological estimates that result from the scaling process by showing they correlate highly with existing measures of ideology from Congress, and with individual-level self-reported political views. Finally, we use these measures to study the relationship between ideology and age, social relationships and ideology, and the relationship between friend ideology and turnout.

Social influence and political mobilization: Further evidence from a randomized experiment in the 2012 U.S. presidential election

A large-scale experiment during the 2010 U.S. Congressional Election demonstrated a positive effect of an online get-out-the-vote message on real world voting behavior. Here, we report results from a replication of the experiment conducted during the U.S. Presidential Election in 2012. In spite of the fact that get-out-the-vote messages typically yield smaller effects during high-stakes elections due to saturation of mobilization efforts from many sources, a significant increase in voting was again observed. Voting also increased significantly among the close friends of those who received the message to go to the polls, and the total effect on the friends was likely larger than the direct effect, suggesting that understanding social influence effects is potentially even more important than understanding the direct effects of messaging. These results replicate earlier work and they add to growing evidence that online social networks can be instrumental for spreading offline behaviors.

Yahtzee: An Anonymized Group Level Matching Procedure

Researchers often face the problem of needing to protect the privacy of subjects while also needing to integrate data that contains personal information from diverse data sources. The advent of computational social science and the enormous amount of data about people that is being collected makes protecting the privacy of research subjects ever more important. However, strict privacy procedures can hinder the process of joining diverse sources of data that contain information about specific individual behaviors. In this paper we present a procedure to keep information about specific individuals from being “leaked” or shared in either direction between two sources of data without need of a trusted third party. To achieve this goal, we randomly assign individuals to anonymous groups before combining the anonymized information between the two sources of data. We refer to this method as the Yahtzee procedure, and show that it performs as predicted by theoretical analysis when we apply it to data from Facebook and public voter records.

Social Endorsement Cues and Political Participation

Which individuals are most responsive to get-out-the-vote (GOTV) messages that emphasize the social aspects of voting? Recent literature has shown that GOTV messages that emphasize the social environment in which an individual is embedded are particularly effective at increasing voting rates. Until now, we have not had good estimates for the types of people for whom social GOTV messages are most effective. We report a new set of disaggregated results of a randomized controlled trial of political mobilization messages delivered to 61 million Facebook users during the 2010 U.S. Congressional elections. The results suggest that social endorsement cues are differentially effective for different types of political behaviors—political expression, information seeking, and voting—and for different kinds of people, based on both demographic and social characteristics, raising new questions about the mechanisms explaining social pressure effects.

The Contagious Spread of Violence Among US Adolescents Through Social Networks

OBJECTIVES To test the hypothesis that violence among US adolescents spreads like a contagious disease through social networks. METHODS Participants were a nationally representative sample of 90 118 US students aged 12 to 18 years who were involved in the National Longitudinal Study of Adolescent Health. Violence was assessed by having participants report the number of times in the preceding 12 months they had been involved in a serious physical fight, had hurt someone badly, and had pulled a weapon on someone. RESULTS Participants were 48% more likely to have been involved in a serious fight, 183% more likely to have hurt someone badly, and 140% more likely to have pulled a weapon on someone if a friend had engaged in the same behavior. The influence spread up to 4 degrees of separation (i.e., friend of friend of friend of friend) for serious fights, 2 degrees for hurting someone badly, and 3 degrees for pulling a weapon on someone. CONCLUSIONS Adolescents were more likely to engage in violent behavior if their friends did the same, and contagion of violence extended beyond immediate friends to friends of friends.

Complex networks: Network healing after loss

Research now shows that human social networks surrounding a person who unexpectedly dies recover from the loss through strengthening of the relationships between friends and acquaintances of the deceased individual. The study demonstrates how individuals change their interaction patterns to support one another during a time of grief.

Contagion in social attitudes about prejudice

Abstract Members of the same household share similar social attitudes, but the source of the similarity in attitudes may be attributed to many processes. This study uses data from a randomized field experiment to identify contagion in attitude change about anti-transgender prejudice. During a face-to-face canvassing experiment, registered voters who answered the door were exposed to either a message encouraging active perspective taking intended to reduce transphobia or a recycling message. Here, I show that the messages delivered to one household member are likely to reduce anti-transgender prejudice in the cohabitants as well. This finding suggests that door-to-door canvassing messages intended to elicit attitude change are likely to be socially transmitted.