Bots increase exposure to negative and inflammatory content in online social systems

Societies are complex systems which tend to polarize into sub-groups of individuals with dramatically opposite perspectives. This phenomenon is reflected -- and often amplified -- in online social networks where, however, humans are no more the only players, and co-exist alongside with social bots, i.e., software-controlled accounts. Analyzing large-scale social data collected during the Catalan referendum for independence on October 1, 2017, consisting of nearly 4 millions Twitter posts generated by almost 1 million users, we identify the two polarized groups of Independentists and Constitutionalists and quantify the structural and emotional roles played by social bots. We show that bots act from peripheral areas of the social system to target influential humans of both groups, bombarding Independentists with violent contents, increasing their exposure to negative and inflammatory narratives and exacerbating social conflict online. Our findings stress the importance of developing countermeasures to unmask these forms of automated social manipulation.Comment: 8 pages, 5 figure

Effectiveness of dismantling strategies on moderated vs. unmoderated online social platforms

Online social networks are the perfect test bed to better understand large-scale human behavior in interacting contexts. Although they are broadly used and studied, little is known about how their terms of service and posting rules affect the way users interact and information spreads. Acknowledging the relation between network connectivity and functionality, we compare the robustness of two different online social platforms, Twitter and Gab, with respect to dismantling strategies based on the recursive censor of users characterized by social prominence (degree) or intensity of inflammatory content (sentiment). We find that the moderated (Twitter) vs unmoderated (Gab) character of the network is not a discriminating factor for intervention effectiveness. We find, however, that more complex strategies based upon the combination of topological and content features may be effective for network dismantling. Our results provide useful indications to design better strategies for countervailing the production and dissemination of anti-social content in online social platforms

Assessing the risks of "infodemics" in response to COVID-19 epidemics

Our society is built on a complex web of interdependencies whose effects become manifest during extraordinary events such as the COVID-19 pandemic, with shocks in one system propagating to the others to an exceptional extent. We analyzed more than 100 millions Twitter messages posted worldwide in 64 languages during the epidemic emergency due to SARS-CoV-2 and classified the reliability of news diffused. We found that waves of unreliable and low-quality information anticipate the epidemic ones, exposing entire countries to irrational social behavior and serious threats for public health. When the epidemics hit the same area, reliable information is quickly inoculated, like antibodies, and the system shifts focus towards certified informational sources. Contrary to mainstream beliefs, we show that human response to falsehood exhibits early-warning signals that might be mitigated with adequate communication strategies.Comment: The dataset analyzed in this paper can be interactively visualized and accessed at https://covid19obs.fbk.eu

Bots influence opinion dynamics without direct human-bot interaction: The mediating role of recommender systems

Bots' ability to influence public discourse is difficult to estimate. Recent studies found that hyperpartisan bots are unlikely to influence public opinion because bots often interact with already highly polarized users. However, previous studies focused on direct human-bot interactions (e.g., retweets, at-mentions, and likes). The present study suggests that political bots, zealots, and trolls may indirectly affect people's views via a platform's content recommendation system's mediating role, thus influencing opinions without direct human-bot interaction. Using an agent-based opinion dynamics simulation, we isolated the effect of a single bot-representing 1% of nodes in a network-on the opinion of rational Bayesian agents when a simple recommendation system mediates the agents' content consumption. We compare this experimental condition with an identical baseline condition where such a bot is absent. Across conditions, we use the same random seed and a psychologically realistic Bayesian opinion update rule so that conditions remain identical except for the bot presence. Results show that, even with limited direct interactions, the mere presence of the bot is sufficient to shift the average population's opinion. Virtually all nodes -not only nodes directly interacting with the bot- shifted towards more extreme opinions. Furthermore, the mere bot's presence significantly affected the internal representation of the recommender system. Overall, these findings offer a proof of concept that bots and hyperpartisan accounts can influence population opinions not only by directly interacting with humans but also by secondary effects, such as shifting platforms recommendation engines internal representations. The mediating role of recommender systems creates indirect causal pathways of algorithmic opinion manipulation.The study was funded by the Max Planck Institute for Human Development. D.B. was partly funded by a research grant from the Institute of Psychology at the Chinese Academy of Sciences

Quantifying echo chamber effects in information spreading over political communication networks

Echo chambers in online social networks, in which users prefer to interact only with ideologically-aligned peers, are believed to facilitate misinformation spreading and contribute to radicalize political discourse. In this paper, we gauge the effects of echo chambers in information spreading phenomena over political communication networks. Mining 12 million Twitter messages, we reconstruct a network in which users interchange opinions related to the impeachment of the former Brazilian President Dilma Rousseff. We define a continuous {political position} parameter, independent of the network's structure, that allows to quantify the presence of echo chambers in the strongly connected component of the network, reflected in two well-separated communities of similar sizes with opposite views of the impeachment process. By means of simple spreading models, we show that the capability of users in propagating the content they produce, measured by the associated spreadability, strongly depends on their attitude. Users expressing pro-impeachment sentiments are capable to transmit information, on average, to a larger audience than users expressing anti-impeachment sentiments. Furthermore, the users' spreadability is correlated to the diversity, in terms of political position, of the audience reached. Our method can be exploited to identify the presence of echo chambers and their effects across different contexts and shed light upon the mechanisms allowing to break echo chambers.Comment: 9 pages, 4 figures. Supplementary Information available as ancillary fil

Social Media, Venue and the Right to a Fair Trial

Judicial failure to recognize social media\u27s influence on juror decision making has identifiable constitutional implications. The Sixth Amendment right to a fair trial demands that courts grant a defendant\u27s change of venue motion when media-generated pretrial publicity invades the unbiased sensibility of those who are asked to sit in judgment. Courts limit publicity suitable for granting a defendant\u27s motion to information culled from newspapers, radio, and television reports. Since about 2014, however, a handful of defendants have introduced social media posts to support their claims of unconstitutional bias in the community. Despite defendants\u27 introduction of negative social media in support of their claims, these same courts have yet to include social media in their evaluation of pretrial publicity bias. But social media is media, and as this article demonstrates, trial court judges faced with deciding change of venue motions have a constitutional obligation to include social media in their evaluations. The collective refusal to treat social media the same as biased television, radio, or print media, suggests an erroneous assumption on the part of lower courts that social media is somehow different. This article identifies three reasons as justification for dismissing social media: social media is too recent a medium to fully understand and analyze, social media is not a legitimate news source, and social media is opinion based. Application of pretrial social media publicity to long-standing Supreme Court change of venue doctrine, coupled with its exploration of scientific and social research on social media influence, debunk these lower court rationalizations. This article demonstrates that the reluctance of courts to consider social media evidence when deciding whether to grant a motion for a change of venue is a violation of any defendant\u27s Sixth Amendment right to a fair trial. On a larger scale, the article demands that courts embrace our new reality. Social media intersects with criminal justice, and our daily lives, in ways that demand judicial recognition

Manipulating the Online Marketplace of Ideas

Social media, the modern marketplace of ideas, is vulnerable to manipulation. Deceptive inauthentic actors impersonate humans to amplify misinformation and influence public opinions. Little is known about the large-scale consequences of such operations, due to the ethical challenges posed by online experiments that manipulate human behavior. Here we introduce a model of information spreading where agents prefer quality information but have limited attention. We evaluate the impact of manipulation strategies aimed at degrading the overall quality of the information ecosystem. The model reproduces empirical patterns about amplification of low-quality information. We find that infiltrating a critical fraction of the network is more damaging than generating attention-grabbing content or targeting influentials. We discuss countermeasures suggested by these insights to increase the resilience of social media users to manipulation, and legal issues arising from regulations aimed at protecting human speech from suppression by inauthentic actors.Comment: 25 pages, 8 figures, 80 reference