publications

2026

1. Political Ideology Shifts in Large Language Models

   Pietro Bernardelle, Stefano Civelli, Leon Fröhling, Riccardo Lunardi, and 2 more authors

   In Information Processing & Management (IPM), Elsevier, 2026

   arXiv
2. LLMs Encode Relevance as a Layer-Wise Cross-Lingual Signal

   Pietro Bernardelle, Samaneh Mohtadi, Stefano Civelli, Joel Mackenzie, and 1 more author

   In Proceedings of the 35th International ACM Conference on Knowledge and Information Management (CIKM), 2026

   arXiv
3. Persona Conditioning as an Assessor-Sensitivity Probe for LLM-Based IR Evaluation

   Samaneh Mohtadi, Pietro Bernardelle, Joel Mackenzie, and Gianluca Demartini

   In Proceedings of the 35th International ACM Conference on Knowledge and Information Management (CIKM), 2026

   arXiv
4. A Shared Geometry of Difficulty in Multilingual Language Models

   Stefano Civelli, Pietro Bernardelle, Nicolò Brunello, and Gianluca Demartini

   In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 2: Short Papers), Jul 2026

   DOI arXiv Bib

   @inproceedings{civelli-etal-2026-shared,
     title = {A Shared Geometry of Difficulty in Multilingual Language Models},
     author = {Civelli, Stefano and Bernardelle, Pietro and Brunello, Nicol{\`o} and Demartini, Gianluca},
     editor = {Liakata, Maria and Moreira, Viviane P. and Zhang, Jiajun and Jurgens, David},
     booktitle = {Proceedings of the 64th Annual Meeting of the {A}ssociation for {C}omputational {L}inguistics (Volume 2: Short Papers)},
     month = jul,
     year = {2026},
     address = {San Diego, California, United States},
     publisher = {Association for Computational Linguistics},
     pages = {796--807},
     isbn = {979-8-89176-391-3},
   }

5. Ideology-Based LLMs for Content Moderation

   Stefano Civelli, Pietro Bernardelle, Nardiena A. Pratama, and Gianluca Demartini

   In ACM transactions on intelligent systems and technology, Jul 2026

   DOI arXiv Bib

   @inproceedings{civelli2025ideological,
     author = {Civelli, Stefano and Bernardelle, Pietro and Pratama, Nardiena A. and Demartini, Gianluca},
     title = {Ideology-Based LLMs for Content Moderation},
     year = {2026},
     publisher = {Association for Computing Machinery},
     address = {New York, NY, USA},
     issn = {2157-6904},
     booktitle = {ACM transactions on intelligent systems and technology},
   }

6. SubData: Bridging Heterogeneous Datasets to Enable Theory-Driven Evaluation of Political and Demographic Perspectives in LLMs

   Pietro Bernardelle, Leon Froehling, Stefano Civelli, and Gianluca Demartini

   In Proceedings of the the fifth edition of NLPerspectives, May 2026

   DOI arXiv Bib

   @inproceedings{bernardelle2026subdata,
     title = {{S}ub{D}ata: Bridging Heterogeneous Datasets to Enable Theory-Driven Evaluation of Political and Demographic Perspectives in {LLM}s},
     author = {Bernardelle, Pietro and Froehling, Leon and Civelli, Stefano and Demartini, Gianluca},
     editor = {Dudy, Shiran and Abercrombie, Gavin and Basile, Valerio and Leonardelli, Elisa and Frenda, Simona},
     booktitle = {Proceedings of the the fifth edition of {NLP}erspectives},
     month = may,
     year = {2026},
     address = {Palma, Mallorca (Spain)},
     publisher = {ELRA Language Resources Association (ELRA)},
     pages = {84--97},
   }

7. Political Advertising on Facebook During the 2022 Australian Federal Election: A Social Identity Perspective

   Stefano Civelli, Pietro Bernardelle, Frank Mols, and Gianluca Demartini

   In Proceedings of the International AAAI Conference on Web and Social Media, May 2026

   PDF arXiv Bib

   @inproceedings{civelli2025politicaladv2022,
     title = {Political Advertising on Facebook During the 2022 Australian Federal Election: A Social Identity Perspective},
     author = {Civelli, Stefano and Bernardelle, Pietro and Mols, Frank and Demartini, Gianluca},
     booktitle = {Proceedings of the International AAAI Conference on Web and Social Media},
     year = {2026}
   }

8. Towards Detecting Persuasion on Social Media: From Model Development to Insights on Persuasion Strategies

   Elyas Meguellati, Stefano Civelli, Pietro Bernardelle, Shazia Sadiq, and 2 more authors

   In Proceedings of the International AAAI Conference on Web and Social Media, May 2026

   PDF arXiv Bib

   @inproceedings{meguellati2026spotting,
     title = {Towards Detecting Persuasion on Social Media: From Model Development to Insights on Persuasion Strategies},
     author = {Meguellati, Elyas and Civelli, Stefano and Bernardelle, Pietro and Sadiq, Shazia and King, Irwin and Demartini, Gianluca},
     booktitle = {Proceedings of the International AAAI Conference on Web and Social Media},
     year = {2026},
   }

2025

1. Mapping and Influencing the Political Ideology of Large Language Models using Synthetic Personas

   Pietro Bernardelle, Leon Fröhling, Stefano Civelli, Riccardo Lunardi, and 2 more authors

   In Companion Proceedings of the ACM on Web Conference, May 2025

   DOI PDF arXiv Bib

   @inproceedings{bernardelle2025mapping,
     title = {Mapping and Influencing the Political Ideology of Large Language Models using Synthetic Personas},
     author = {Bernardelle, Pietro and Fr\"{o}hling, Leon and Civelli, Stefano and Lunardi, Riccardo and Roitero, Kevin and Demartini, Gianluca},
     booktitle = {Companion Proceedings of the ACM on Web Conference},
     pages = {864--867},
     year = {2025}
   }

2. The Impact of Persona-based Political Perspectives on Hateful Content Detection

   Stefano Civelli, Pietro Bernardelle, and Gianluca Demartini

   In Companion Proceedings of the ACM on Web Conference, May 2025

   DOI PDF arXiv Bib

   @inproceedings{civelli2025impact,
     author = {Civelli, Stefano and Bernardelle, Pietro and Demartini, Gianluca},
     title = {The Impact of Persona-based Political Perspectives on Hateful Content Detection},
     booktitle = {Companion Proceedings of the ACM on Web Conference},
     pages = {1963--1968},
     year = {2025}
   }

2024

1. Optimizing LLMs with Direct Preferences: A Data Efficiency Perspective

   Pietro Bernardelle and Gianluca Demartini

   In Proceedings of the 2024 Annual International ACM SIGIR Conference on Research and Development in Information Retrieval in the Asia Pacific Region, May 2024

   DOI PDF arXiv Bib

   @inproceedings{bernardelle2024optimizing,
     title = {Optimizing LLMs with Direct Preferences: A Data Efficiency Perspective},
     author = {Bernardelle, Pietro and Demartini, Gianluca},
     booktitle = {Proceedings of the 2024 Annual International ACM SIGIR Conference on Research and Development in Information Retrieval in the Asia Pacific Region},
     pages = {236--240},
     year = {2024}
   }