Towards Faithful and Controllable Personalization via Critique-Post-Edit Reinforcement Learning

Meiling Tao, Chenghao Zhu, Dongyi Ding, Tiannan Wang, Yuchen Eleanor Jiang, Wangchunshu Zhou


Abstract
Reinforcement learning has driven the largest post-training gains on tasks with verifiable rewards, such as code and math. Extending this success to subjective tasks remains difficult: good responses must satisfy multiple soft criteria simultaneously, and no scalar reward can indicate which aspect of a response should improve. Personalization is a clear instance of this. A personalized response must balance helpfulness, user-specific relevance, and naturalness, yet standard verifiers cannot localize which specific dimension needs improvement. In this regime, supervised fine-tuning quickly saturates, and PPO with Bradley-Terry reward models is prone to reward hacking, especially via length bias, producing verbose or superficially personalized responses. We propose Critique-Post-Edit, an RL framework that combines (1) a personalized Generative Reward Model (GRM) producing multi-dimensional scores and natural-language critiques, and (2) a critique-guided editing step that turns feedback into nearby alternative responses for policy learning. The reward signal stays scalar; our contribution is to use personalized critiques to construct more informative local alternatives (responses close to the on-policy rollout in edit distance) during training. Under length-controlled evaluation, Critique-Post-Edit improves over PPO by 11.0 and 11.6 win-rate points on Qwen2.5-7B and 14B models, respectively. Notably, the 14B model matches or outperforms GPT-4.1 on the evaluated benchmarks. A static mechanism study further shows that critique-guided edits stay more local than extra rollouts and shift scores more favorably than generic rewrites. All of our experiments are on personalization; systematic evaluation on other subjective tasks is left to future work.
Anthology ID:
2026.findings-emnlp.1968
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
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SIGDAT
Publisher:
Association for Computational Linguistics
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Pages:
41965–41985
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URL:
https://aclanthology.org/2026.findings-emnlp.1968/
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Cite (ACL):
Meiling Tao, Chenghao Zhu, Dongyi Ding, Tiannan Wang, Yuchen Eleanor Jiang, and Wangchunshu Zhou. 2026. Towards Faithful and Controllable Personalization via Critique-Post-Edit Reinforcement Learning. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 41965–41985, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Towards Faithful and Controllable Personalization via Critique-Post-Edit Reinforcement Learning (Tao et al., Findings 2026)
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https://aclanthology.org/2026.findings-emnlp.1968.pdf