Brackbill, Devon

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Now showing 1 - 3 of 3
  • Publication
    Support or Competition? How Online Social Networks Increase Physical Activity: A Randomized Controlled Trial
    (2016-12-01) Zhang, Jingwen; Brackbill, Devon; Yang, Sijia; Centola, Damon; Becker, Joshua; Herbert, Natalie
    To identify what features of online social networks can increase physical activity, we conducted a 4-arm randomized controlled trial in 2014 in Philadelphia, PA. Students (n = 790, mean age = 25.2) at an university were randomly assigned to one of four conditions composed of either supportive or competitive relationships and either with individual or team incentives for attending exercise classes. The social comparison condition placed participants into 6-person competitive networks with individual incentives. The social support condition placed participants into 6-person teams with team incentives. The combined condition with both supportive and competitive relationships placed participants into 6-person teams, where participants could compare their team's performance to 5 other teams' performances. The control condition only allowed participants to attend classes with individual incentives. Rewards were based on the total number of classes attended by an individual, or the average number of classes attended by the members of a team. The outcome was the number of classes that participants attended. Data were analyzed using multilevel models in 2014. The mean attendance numbers per week were 35.7, 38.5, 20.3, and 16.8 in the social comparison, the combined, the control, and the social support conditions. Attendance numbers were 90% higher in the social comparison and the combined conditions (mean = 1.9, SE = 0.2) in contrast to the two conditions without comparison (mean = 1.0, SE = 0.2) (p = 0.003). Social comparison was more effective for increasing physical activity than social support and its effects did not depend on individual or team incentives.
  • Publication
    The Network Structure Of Collective Innovation
    (2017-01-01) Brackbill, Devon
    Prior research on how to design collaboration networks among scientists, engineers, and strategists surprisingly predicts that inefficient networks that slow down the rate of collaboration will lead to better performance on complex problems. However, empirical research has provided mixed evidence for these ideas. Here, we test this theory using an online Data Science Competition that experimentally manipulates the network efficiency of teams working on a complex problem. The results support the idea that less efficient collaboration networks increase collective performance on complex problems. The results have important implications for designing problem-solving teams in numerous domains.
  • Publication
    Efficacy and Causal Mechanism of an Online Social Media Intervention to Increase Physical Activity: Results of a Randomized Controlled Trial
    (2015-01-01) Zhang, Jingwen; Brackbill, Devon; Yang, Sijia; Centola, Damon
    Objective: To identify what features of social media – promotional messaging or peer networks – can increase physical activity. Method: A 13-week social media-based exercise program was conducted at a large Northeastern university in Philadelphia, PA. In a randomized controlled trial, 217 graduate students from the University were randomized to three conditions: a control condition with a basic online program for enrolling in weekly exercise classes led by instructors of the University for 13 weeks, a media condition that supplemented the basic program with weekly online promotional media messages that encourage physical activity, and a social condition that replaced the media content with an online network of four to six anonymous peers composed of other participants of the program, in which each participant was able to see their peers' progress in enrolling in classes. The primary outcome was the number of enrollments in exercise classes, and the secondary outcomes were self-reported physical activities. Data were collected in 2014. Results: Participants enrolled in 5.5 classes on average. Compared with enrollment in the control condition (mean = 4.5), promotional messages moderately increased enrollment (mean = 5.7, p = 0.08), while anonymous social networks significantly increased enrollment (mean = 6.3, p = 0.02). By the end of the program, participants in the social condition reported exercising moderately for an additional 1.6 days each week compared with the baseline, which was significantly more than an additional 0.8 days in the control condition. Conclusion: Social influence from anonymous online peers was more successful than promotional messages for improving physical activity. Clinical Trial Registration: ClinicalTrials.gov: NCT02267369.