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Online Debates
Polarization, echo chambers and polluted information environments: measuring, modelling and mitigating the pollution of online debates.
The Web and online social networks have turned everyone into a potential news medium. Direct, unfiltered communication makes access to information more democratic, but it also exposes readers to manipulative, biased and disinformative content.
The pollution of public debate is a significant issue for modern democracies. With no recognised authority vouching for quality, and with recommender systems that reinforce confirmation bias, it becomes hard to judge the information people actually consume. We study these Polluted Information Environments (PIEs) with data-driven network models.
Why debates get polluted
Algorithmic bias
Recommendation and advertising systems feed confirmation bias and help build alternative realities.
Polarization & echo chambers
Like-minded users cluster together and the debate fragments, amplifying extreme positions.
Objectives
- 1
Build a data-driven framework for online debates, combining AI/ML data enrichment with higher-order, feature-rich and dynamic network models.
- 2
Apply it to Polluted Information Environments to study how they form and evolve, and how predictable their evolution is.
- 3
Measure pollution with statistically sound inference, evaluate mitigation strategies and estimate how predictable pollution dynamics are.
Related publications
All publications-
Quantifying opinion homophily in online social networks: A bounded confidence perspective
arXiv (Cornell University)@article{luan2026quantifying, title = {Quantifying opinion homophily in online social networks: A bounded confidence perspective}, author = {Luan, Yangyang and Ancona, Camilla and Bernardo, Carmela and Pansanella, Valentina and Iudice, Francesco Lo and Rossetti, Giulio and Vasca, Francesco and Wu, Xiaoqun and Altafini, Claudio}, journal = {arXiv (Cornell University)}, year = {2026}, doi = {10.48550/arxiv.2604.23157}, url = {https://doi.org/10.48550/arxiv.2604.23157}, publisher = {Cornell University}, } -
Low-Vocality Engagement Shapes Online Participation
arXiv (Cornell University)@article{mesina2026vocality, title = {Low-Vocality Engagement Shapes Online Participation}, author = {Mesina, Veronica and Failla, Andrea and Pappalardo, Luca and Rossetti, Giulio}, journal = {arXiv (Cornell University)}, year = {2026}, doi = {10.48550/arxiv.2606.21665}, url = {https://doi.org/10.48550/arxiv.2606.21665}, publisher = {Cornell University}, } -
Joint Effects of Recommender Systems and Network Structure on the Visibility of Content and Creators
arXiv (Cornell University)@article{morini2026joint, title = {Joint Effects of Recommender Systems and Network Structure on the Visibility of Content and Creators}, author = {Morini, Virginia and Pansanella, Valentina and Pappalardo, Luca and Pedreschi, Dino and Rossetti, Giulio}, journal = {arXiv (Cornell University)}, year = {2026}, doi = {10.48550/arxiv.2607.00258}, url = {https://doi.org/10.48550/arxiv.2607.00258}, publisher = {Cornell University}, } -
Structure, Topics, and Diffusion Effects of Bluesky Starter Packs
arXiv preprint arXiv:2608.17489@article{failla2026starter, title = {Structure, Topics, and Diffusion Effects of Bluesky Starter Packs}, author = {Failla, Andrea and Freitas, V. and Rossetti, Giulio and Ferreira, C.}, journal = {arXiv preprint arXiv:2608.17489}, year = {2026}, } -
Simulating Toxicity Diffusion with Moderation-Aware SEIZ Models
In ECML-PKDD Workshops@inproceedings{pollacci2026toxicity, title = {Simulating Toxicity Diffusion with Moderation-Aware SEIZ Models}, author = {Pollacci, Laura and Milli, Letizia and Rossetti, Giulio and Guidotti, Riccardo}, booktitle = {ECML-PKDD Workshops}, year = {2026}, } -
Out-of-Network Attention Dynamics on Bluesky
arXiv preprint arXiv:2610.01971@article{failla2026outofnetwork, title = {Out-of-Network Attention Dynamics on Bluesky}, author = {Failla, Andrea and Mesina, Veronica and Rossetti, Giulio}, journal = {arXiv preprint arXiv:2610.01971}, year = {2026}, } -
Whose Voice Matters? Authority and Influence in the Italian Twitter Debates on Covid-19
In Studies in computational intelligence@incollection{mesina2025whose, title = {Whose Voice Matters? Authority and Influence in the Italian Twitter Debates on Covid-19}, author = {Mesina, Veronica Valenzuela and Failla, Andrea and Morini, Virginia and Rossetti, Giulio}, booktitle = {Studies in computational intelligence}, year = {2025}, pages = {352--363}, doi = {10.1007/978-3-031-82431-9_29}, url = {https://doi.org/10.1007/978-3-031-82431-9_29}, publisher = {Springer Nature}, } -
TETRA: TExtual TRust Analyzer for a Gricean Approach to Social Networks
In Lecture notes in computer science@incollection{mazzoni2025tetra, title = {TETRA: TExtual TRust Analyzer for a Gricean Approach to Social Networks}, author = {Mazzoni, Federico and Mazzarino, Simona and Rossetti, Giulio}, booktitle = {Lecture notes in computer science}, year = {2025}, pages = {364--378}, doi = {10.1007/978-3-031-78980-9_23}, url = {https://doi.org/10.1007/978-3-031-78980-9_23}, publisher = {Springer Science+Business Media}, } -
Quantifying Attraction to Extreme Opinions in Online Debates
In Lecture notes in computer science@incollection{perra2025quantifying, title = {Quantifying Attraction to Extreme Opinions in Online Debates}, author = {Perra, Davide and Failla, Andrea and Rossetti, Giulio}, booktitle = {Lecture notes in computer science}, year = {2025}, pages = {411--424}, doi = {10.1007/978-3-031-78980-9_26}, url = {https://doi.org/10.1007/978-3-031-78980-9_26}, publisher = {Springer Science+Business Media}, } -
Characterizing User Archetypes and Discussions on Social Hypernetworks
Big Data and Cognitive Computing, 9(9)@article{failla2025characterizing, title = {Characterizing User Archetypes and Discussions on Social Hypernetworks}, author = {Failla, Andrea and Citraro, Salvatore and Rossetti, Giulio and Cauteruccio, Francesco}, journal = {Big Data and Cognitive Computing}, year = {2025}, volume = {9}, number = {9}, pages = {236--236}, doi = {10.3390/bdcc9090236}, url = {https://doi.org/10.3390/bdcc9090236}, publisher = {Multidisciplinary Digital Publishing Institute}, } -
Beyond Boundaries: Capturing Social Segregation on Hypernetworks
In Lecture notes in computer science@incollection{failla2025beyond, title = {Beyond Boundaries: Capturing Social Segregation on Hypernetworks}, author = {Failla, Andrea and Rossetti, Giulio and Cauteruccio, Francesco}, booktitle = {Lecture notes in computer science}, year = {2025}, pages = {40--55}, doi = {10.1007/978-3-031-78541-2_3}, url = {https://doi.org/10.1007/978-3-031-78541-2_3}, publisher = {Springer Science+Business Media}, } -
“I’m in the Bluesky Tonight”: Insights from a year worth of social data
PLoS ONE, 19(11)@article{failla2024bluesky, title = {“I’m in the Bluesky Tonight”: Insights from a year worth of social data}, author = {Failla, Andrea and Rossetti, Giulio}, journal = {PLoS ONE}, year = {2024}, volume = {19}, number = {11}, pages = {e0310330--e0310330}, doi = {10.1371/journal.pone.0310330}, url = {https://doi.org/10.1371/journal.pone.0310330}, publisher = {Public Library of Science}, } -
From Perils to Possibilities: Understanding how Human (and AI) Biases affect Online Fora
arXiv (Cornell University)@article{morini2024perils, title = {From Perils to Possibilities: Understanding how Human (and AI) Biases affect Online Fora}, author = {Morini, Virginia and Pansanella, Valentina and Abramski, Katherine and Cau, Erica and Failla, Andrea and Citraro, Salvatore and Rossetti, Giulio}, journal = {arXiv (Cornell University)}, year = {2024}, doi = {10.48550/arxiv.2403.14298}, url = {https://doi.org/10.48550/arxiv.2403.14298}, publisher = {Cornell University}, } -
Characterizing User Archetypes and Discussions on Scored.co
arXiv (Cornell University)@article{failla2024characterizing, title = {Characterizing User Archetypes and Discussions on Scored.co}, author = {Failla, Andrea and Citraro, Salvatore and Rossetti, Giulio and Cauteruccio, Francesco}, journal = {arXiv (Cornell University)}, year = {2024}, doi = {10.48550/arxiv.2407.21753}, url = {https://doi.org/10.48550/arxiv.2407.21753}, publisher = {Cornell University}, } -
A survey on the impacts of recommender systems on users, items, and human-AI ecosystems
arXiv (Cornell University)@article{pappalardo2024survey, title = {A survey on the impacts of recommender systems on users, items, and human-AI ecosystems}, author = {Pappalardo, Luca and Citraro, Salvatore and Cornacchia, Giuliano and Nanni, Mirco and Pansanella, Valentina and Rossetti, Giulio and Gezi̇ci, Gizem and Giannotti, Fosca and Lalli, Margherita and Mauro, Giovanni and Barlacchi, Gabriele and Gambetta, Daniele and Morini, Virginia and Pedreschi, Dino and Ferragina, Emanuele}, journal = {arXiv (Cornell University)}, year = {2024}, doi = {10.48550/arxiv.2407.01630}, url = {https://doi.org/10.48550/arxiv.2407.01630}, publisher = {Cornell University}, } -
A framework for the diachronic and linguistic analysis of online polarized discussions
In Complex networks@inproceedings{cau2023framework, title = {A framework for the diachronic and linguistic analysis of online polarized discussions}, author = {Cau, Erica and Morini, Virginia and Rossetti, Giulio}, booktitle = {Complex networks}, year = {2023}, } -
Higher-Order Estimate of Open Mindedness in Online Political Discussions
In International School and Conference on Network Science@inproceedings{ferro2023higher, title = {Higher-Order Estimate of Open Mindedness in Online Political Discussions}, author = {Ferro, Giulia and Pansanella, Valentina and Rossetti, Giulio}, booktitle = {International School and Conference on Network Science}, year = {2023}, } -
Mass Media Impact on Opinion Evolution in Biased Digital Environments: a Bounded Confidence Model
Scientific Reports@article{pansanella2023mass, title = {Mass Media Impact on Opinion Evolution in Biased Digital Environments: a Bounded Confidence Model}, author = {Pansanella, Valentina and Sirbu, Alina and Kert{\'e}sz, J{\'a}nos and Rossetti, Giulio}, year = {2023}, journal = {Scientific Reports}, } -
Trends and Topics: Characterizing Echo Chambers’ Topological Stability and In-group Attitudes
arXiv preprint arXiv:2307.15610@article{cau2023trends, title = {Trends and Topics: Characterizing Echo Chambers' Topological Stability and In-group Attitudes}, author = {Cau, Erica and Morini, Virginia and Rossetti, Giulio}, journal = {arXiv preprint arXiv:2307.15610}, year = {2023}, } -
I like you if you are like me: How the Italians’ opinion on Twitter about migrants changed after the 2022 Russo-Ukrainian conflict
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Modeling algorithmic bias: simplicial complexes and evolving network topologies
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Change my Mind: Data Driven Estimate of Open-Mindedness from Political Discussions
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Attributed Stream-Hypernetwork analysis: Homophilic Behaviors in Pairwise and Group Political Discussions on Reddit
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Will You Take the Knee? Italian Twitter Echo Chambers’ Genesis during EURO 2020
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Toward a Standard Approach for Echo Chamber Detection: Reddit Case Study
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Sockpuppet Detection: a Telegram case study
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From mean-field to complex topologies: network effects on the algorithmic bias model
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Capturing Political Polarization of Reddit Submissions in the Trump Era
In 28th Symposium on Advanced Database Systems@inproceedings{morini2020capturing, title = {Capturing Political Polarization of Reddit Submissions in the Trump Era}, author = {Morini, Virginia and Pollacci, Laura and Rossetti, Giulio}, booktitle = {28th Symposium on Advanced Database Systems}, year = {2020}, } -
Opinion dynamic modeling of fake news perception
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