When Harry Meets Superman: The Role of The Interlocutor in Persona-Based Dialogue Generation

Daniela Occhipinti, Marco Guerini, Malvina Nissim


Abstract
Endowing dialogue agents with persona information has proven to significantly improve the consistency and diversity of their generations. While much focus has been placed on aligning dialogues with provided personas, the adaptation to the interlocutor’s profile remains largely underexplored. In this work, we investigate three key aspects: (1) a model’s ability to align responses with both the provided persona and the interlocutor’s; (2) its robustness when dealing with familiar versus unfamiliar interlocutors and topics, and (3) the impact of additional fine-tuning on specific persona-based dialogues. We evaluate dialogues generated with diverse speaker pairings and topics, framing the evaluation as an author identification task and employing both LLM-as-a-judge and human evaluations. By systematically masking or disclosing information about interlocutor, we assess its impact on dialogue generation. Results show that access to the interlocutor’s persona improves the recognition of the target speaker, while masking it does the opposite. Although models generalise well across topics, they struggle with unfamiliar interlocutors. Finally, we found that in zero-shot settings, LLMs often copy biographical details, facilitating identification but trivialising the task.
Anthology ID:
2025.acl-long.879
Volume:
Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venue:
ACL
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
17964–17985
Language:
URL:
https://preview.aclanthology.org/ingestion-acl-25/2025.acl-long.879/
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Bibkey:
Cite (ACL):
Daniela Occhipinti, Marco Guerini, and Malvina Nissim. 2025. When Harry Meets Superman: The Role of The Interlocutor in Persona-Based Dialogue Generation. In Proceedings of the 63rd Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 17964–17985, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
When Harry Meets Superman: The Role of The Interlocutor in Persona-Based Dialogue Generation (Occhipinti et al., ACL 2025)
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PDF:
https://preview.aclanthology.org/ingestion-acl-25/2025.acl-long.879.pdf