eprintid: 3684 rev_number: 7 eprint_status: archive userid: 69 dir: disk0/00/00/36/84 datestamp: 2017-04-18 08:25:38 lastmod: 2017-04-18 08:25:38 status_changed: 2017-04-18 08:25:38 type: article metadata_visibility: show creators_name: Vicario, Michela Del creators_name: Zollo, Fabiana creators_name: Caldarelli, Guido creators_name: Scala, Antonio creators_name: Quattrociocchi, Walter creators_id: creators_id: fabiana.zollo@imtlucca.it creators_id: guido.caldarelli@imtlucca.it creators_id: creators_id: walter.quattrociocchi@imtlucca.it title: Mapping social dynamics on Facebook: The Brexit debate ispublished: pub subjects: H1 subjects: HA subjects: HM divisions: CSA full_text_status: none keywords: Collective debates; Polarization; Online social networks abstract: Abstract Nowadays users get informed and shape their opinion through social media. However, the disintermediated access to contents does not guarantee quality of information. Selective exposure and confirmation bias, indeed, have been shown to play a pivotal role in content consumption and information spreading. Users tend to select information adhering (and reinforcing) their worldview and to ignore dissenting information. This pattern elicits the formation of polarized groups – i.e., echo chambers – where the interaction with like-minded people might even reinforce polarization. In this work we address news consumption around Brexit in {UK} on Facebook. In particular, we perform a massive analysis on more than 1 million users interacting with Brexit related posts from the main news providers between January and July 2016. We show that consumption patterns elicit the emergence of two distinct communities of news outlets. Furthermore, to better characterize inner group dynamics, we introduce a new technique which combines automatic topic extraction and sentiment analysis. We compare how the same topics are presented on posts and the related emotional response on comments finding significant differences in both echo chambers and that polarization influences the perception of topics. Our results provide important insights about the determinants of polarization and evolution of core narratives on online debating. date: 2017 date_type: published publication: Social Networks volume: 50 publisher: Elsevier pagerange: 6 - 16 refereed: TRUE issn: 0378-8733 official_url: http://www.sciencedirect.com/science/article/pii/S0378873316304166 citation: Vicario, Michela Del and Zollo, Fabiana and Caldarelli, Guido and Scala, Antonio and Quattrociocchi, Walter Mapping social dynamics on Facebook: The Brexit debate. Social Networks, 50. 6 - 16. ISSN 0378-8733 (2017)