PTCG: Persona-guided Tree-based Counterargument Generation

Eunbeen Son, Yohan Jo, Joonsuk Park, JinYeong Bak


Abstract
The ability to generate counterarguments is important for critical thinking and balanced discourse, yet existing approaches typically produce only a single counterargument, failing to capture the diversity and persuasiveness required in real-world debates. To address this limitation, we propose Persona-guided Tree-based Counterargument Generation (PTCG), a framework that combines Tree-of-Thoughts–inspired step-wise generation and pruning with speaker persona selection. By estimating the author’s persona from the original argument and incorporating speaker personas representing distinct perspectives, PTCG operationalizes perspective-taking and enables the generation of diverse counterarguments. Results from LLM-as-a-Judge, classifier-based assessment, and human evaluations indicate that PTCG shows consistent improvements in both the diversity and persuasiveness of counterarguments compared to baseline methods.
Anthology ID:
2026.findings-emnlp.133
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
2705–2734
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.133/
DOI:
Bibkey:
Cite (ACL):
Eunbeen Son, Yohan Jo, Joonsuk Park, and JinYeong Bak. 2026. PTCG: Persona-guided Tree-based Counterargument Generation. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 2705–2734, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
PTCG: Persona-guided Tree-based Counterargument Generation (Son et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.133.pdf