Should I Trust You? Detecting Deception in Negotiations using Counterfactual RL

Wichayaporn Wongkamjan, Yanze Wang, Feng Gu, Denis Peskoff, Jonathan K. Kummerfeld, Jonathan May, Jordan Lee Boyd-Graber


Abstract
An increasingly common socio-technical problem is people being taken in by offers that sound “too good to be true”, where persuasion and trust shape decision-making. This paper investigates how AI can help detect these deceptive scenarios. We analyze how humans strategically deceive each other in Diplomacy, a board game that requires both natural language communication and strategic reasoning. This requires extracting logical forms representing proposals—agreements that players suggest during communication—and computing their relative rewards using agents’ value functions. Combined with text-based features, this can improve our deception detection. Our method detects human deception with a high precision when compared to a Large Language Model approach that flags many true messages as deceptive. Future human-AI interaction tools can build on our methods for deception detection by triggering friction to give users a chance of interrogating suspicious proposals.
Anthology ID:
2025.findings-acl.1287
Volume:
Findings of the Association for Computational Linguistics: ACL 2025
Month:
July
Year:
2025
Address:
Vienna, Austria
Editors:
Wanxiang Che, Joyce Nabende, Ekaterina Shutova, Mohammad Taher Pilehvar
Venue:
Findings
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
25099–25113
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URL:
https://preview.aclanthology.org/display_plenaries/2025.findings-acl.1287/
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Bibkey:
Cite (ACL):
Wichayaporn Wongkamjan, Yanze Wang, Feng Gu, Denis Peskoff, Jonathan K. Kummerfeld, Jonathan May, and Jordan Lee Boyd-Graber. 2025. Should I Trust You? Detecting Deception in Negotiations using Counterfactual RL. In Findings of the Association for Computational Linguistics: ACL 2025, pages 25099–25113, Vienna, Austria. Association for Computational Linguistics.
Cite (Informal):
Should I Trust You? Detecting Deception in Negotiations using Counterfactual RL (Wongkamjan et al., Findings 2025)
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https://preview.aclanthology.org/display_plenaries/2025.findings-acl.1287.pdf