StanceAgent-R1: Agentic Reinforcement Learning for Zero-Shot Conversational Stance Detection

Xing Li, Jinzhong Ning, Yijia Zhang


Abstract
Conversational stance detection requires identifying the stance of a current utterance toward a target within its dialogue context. Existing methods often rely on sequential encoding, fixed knowledge-integration pipelines, or uniform reasoning strategies, which limits their ability to capture cross-turn dependencies and adapt to instance-specific needs. We propose StanceAgent-R1, an agentic reinforcement learning framework that adaptively routes each instance to evidence-path selection and/or knowledge elicitation. The model is first warm-started with rejection-sampled expert trajectories and then optimized with a progressive trajectory-faithful reward that encourages correct, well-formed, and route-consistent reasoning. Experiments on ZS-CSD, MT-CSD, and C-MTCSD show that StanceAgent-R1 achieves state-of-the-art performance, with further analyses confirming the effectiveness of its agentic design and reward strategy.
Anthology ID:
2026.findings-emnlp.1129
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:
23895–23919
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1129/
DOI:
10.18653/2026.findings-emnlp.1129
Bibkey:
Cite (ACL):
Xing Li, Jinzhong Ning, and Yijia Zhang. 2026. StanceAgent-R1: Agentic Reinforcement Learning for Zero-Shot Conversational Stance Detection. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 23895–23919, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
StanceAgent-R1: Agentic Reinforcement Learning for Zero-Shot Conversational Stance Detection (Li et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1129.pdf