The Thin Line Between Comprehension and Persuasion in LLMs

Adrian de Wynter, Tangming Yuan


Abstract
Large language models (LLMs) are excellent at maintaining high-level, convincing dialogue, but it remains unclear whether their persuasive success reflects genuine understanding of the discourse. We examine this question through informal debates between humans and LLMs, first by measuring their persuasive skills, and then by relating these to their understanding of what is being talked about: namely, their comprehension of argumentative structures and the pragmatic context on the same debates. We find that LLMs effectively maintain coherent, persuasive debates, and can sway the beliefs of both participants and audiences. We also note that awareness or suspicion of AI involvement encourage people to be more critical of the arguments made. However, we also find that LLMs are unable to show comprehension of deeper dialogical structures, such as argument quality or existence of supporting premises. Our results reveal a disconnect between LLM comprehension and dialogical skills, raising ethical and practical concerns on their deployment on explanation-critical contexts. From an argumentation-theoretical perspective, we experimentally question whether an agent, if it can convincingly maintain a dialogue, is required to show it knows what is talking about.
Anthology ID:
2026.findings-acl.329
Volume:
Findings of the Association for Computational Linguistics: ACL 2026
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
6603–6631
Language:
URL:
https://preview.aclanthology.org/ingest-acl/2026.findings-acl.329/
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Bibkey:
Cite (ACL):
Adrian de Wynter and Tangming Yuan. 2026. The Thin Line Between Comprehension and Persuasion in LLMs. In Findings of the Association for Computational Linguistics: ACL 2026, pages 6603–6631, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
The Thin Line Between Comprehension and Persuasion in LLMs (de Wynter & Yuan, Findings 2026)
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https://preview.aclanthology.org/ingest-acl/2026.findings-acl.329.pdf
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