arXiv:2601.22664cs.AI2026-01被引 18

通过实时捕捉策略模型变化,提升奖励模型对齐效果。

Real-Time Aligned Reward Model beyond Semantics

  • 利用策略模型的隐藏状态实现动态对齐
  • 缓解因策略分布漂移导致的奖励偏差
  • 适合追求高稳定性的RLHF应用

基于人类反馈的强化学习(RLHF)是使大语言模型对齐人类偏好关键方法,但易受奖励过优化影响:策略模型会过拟合奖励模型,利用虚假奖励模式而非真实意图。现有缓解方法主要依赖表面语义信息,无法有效应对奖励模型与策略模型间因连续策略分布漂移造成的错位,导致奖励差异持续扩大,加剧过优化问题。为此,本文提出R2M(Real-Time Aligned Reward Model),一种轻量级RLHF框架。R2M突破传统仅依赖预训练语言模型语义表示的奖励模型局限,转而利用策略模型在强化学习过程中的演化隐藏状态(即策略反馈),实现与策略实时分布偏移的对齐。该工作为通过实时利用策略反馈提升奖励模型性能开辟了新方向。

原文摘要 · Abstract (English)

Reinforcement Learning from Human Feedback (RLHF) is a pivotal technique for aligning large language models (LLMs) with human preferences, yet it is susceptible to reward overoptimization, in which policy models overfit to the reward model, exploit spurious reward patterns instead of faithfully capturing human intent. Prior mitigations primarily relies on surface semantic information and fails to efficiently address the misalignment between the reward model (RM) and the policy model caused by continuous policy distribution shifts. This inevitably leads to an increasing reward discrepancy, exacerbating reward overoptimization. To address these limitations, we introduce R2M (Real-Time Aligned Reward Model), a novel lightweight RLHF framework. R2M goes beyond vanilla reward models that solely depend on the semantic representations of a pretrained LLM. Instead, it leverages the evolving hidden states of the policy (namely policy feedback) to align with the real-time distribution shift of the policy during the RL process. This work points to a promising new direction for improving the performance of reward models through real-time utilization of feedback from policy models.

RLHF奖励模型对齐

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