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arXiv 2602.09305cs.LG
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基于强化学习的LLM推理中的奖励建模:设计、挑战与评估

Reward Modeling for Reinforcement Learning-Based LLM Reasoning: Design, Challenges, and Evaluation

University of Houston(得克萨斯大学);The Ohio State University(俄亥俄州立大学)

Pei-Chi Pan, Yingbin Liang, Sen Lin

AI总结:

本文探讨了奖励建模在提升LLM推理性能中的关键作用,提出了一种以推理为中心的分类视角,分析了奖励机制、奖励黑客问题及评估挑战,旨在构建更稳健、可验证的推理模型。

摘要:

大型语言模型(LLMs)展现出变革性潜力,但其推理仍不一致且不可靠。基于强化学习(RL)的微调是改进的关键机制,但其有效性根本上由奖励设计决定。尽管重要,奖励建模与核心LLM挑战——如评估偏差、幻觉、分布偏移和高效学习——之间的关系仍不明确。本文认为,奖励建模不仅是实现细节,而是推理对齐的核心架构,影响模型学习内容、泛化能力及输出可信度。我们引入了以推理为中心的强化学习(RARL),一种将多样化奖励范式组织为多步推理的分类视角。在此视角下,我们提出奖励机制的分类,分析奖励黑客作为普遍失败模式,并探讨奖励信号如何统一从推理时间扩展到幻觉缓解的挑战。我们进一步批判性评估现有基准,突出数据污染和奖励不匹配等漏洞,并概述更稳健评估的方向。通过整合碎片化的研究线索并明确奖励设计与基本推理能力之间的相互作用,本文为构建稳健、可验证和可信的推理模型提供了基础路线图。

英文摘要:

Large Language Models (LLMs) demonstrate transformative potential, yet their reasoning remains inconsistent and unreliable. Reinforcement learning (RL)-based fine-tuning is a key mechanism for improvement, but its effectiveness is fundamentally governed by reward design. Despite its importance, the relationship between reward modeling and core LLM challenges--such as evaluation bias, hallucination, distribution shift, and efficient learning--remains poorly understood. This work argues that reward modeling is not merely an implementation detail but a central architect of reasoning alignment, shaping what models learn, how they generalize, and whether their outputs can be trusted. We introduce Reasoning-Aligned Reinforcement Learning (RARL), a reasoning-centric taxonomic perspective that organizes diverse reward paradigms for multi-step reasoning. Within this perspective, we present a taxonomy of reward mechanisms, analyze reward hacking as a pervasive failure mode, and examine how reward signals unify challenges ranging from inference-time scaling to hallucination mitigation. We further critically evaluate existing benchmarks, highlighting vulnerabilities such as data contamination and reward misalignment, and outline directions for more robust evaluation. By integrating fragmented research threads and clarifying the interplay between reward design and fundamental reasoning capabilities, this work provides a foundational roadmap for building reasoning models that are robust, verifiable, and trustworthy.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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