arXiv:2412.10529cs.LGcs.CL2024-12被引 1

通过解耦对齐问题,提升大模型强化学习的反馈质量与训练效率。

Solving the Inverse Alignment Problem for Efficient RLHF

  • 基于逆强化学习思路,重构奖励模型的训练方式。
  • 在相同数据下,收敛速度更快,对齐效果更优。
  • 适合追求高效对齐的大模型训练团队参考。

为强化学习中的人类反馈(RLHF)构建高质量偏好数据集成本高昂且困难。因此,研究者常在大规模离线数据集上训练奖励模型,这些数据集整合了多种生成源及评分/对齐策略。我们假设这种聚合导致奖励模型得分平均化,削弱信号并影响对齐效果。受逆强化学习启发,我们提出语言模型训练中的‘逆对齐问题’,目标是在固定智能体和离线偏好数据集的前提下优化评判器的奖励。我们假设解决此问题可提供更清晰的策略行为反馈,从而提升奖励模型质量。为此,我们在RLHF过程中,反复用与周期性冻结策略一致的数据子集微调奖励模型,相较于使用不匹配或分布外的奖励模型,实验表明该方法能实现更优对齐与更快收敛。

原文摘要 · Abstract (English)

Collecting high-quality preference datasets for reinforcement learning from human feedback (RLHF) is resource-intensive and challenging. As a result, researchers often train reward models on extensive offline datasets which aggregate diverse generation sources and scoring/alignment policies. We hypothesize that this aggregation has an averaging effect on reward model scores, which limits signal and impairs the alignment process. Inspired by the field of inverse RL, we define the 'inverse alignment problem' in language model training, where our objective is to optimize the critic's reward for a fixed actor and a fixed offline preference dataset. We hypothesize that solving the inverse alignment problem will improve reward model quality by providing clearer feedback on the policy's current behavior. To that end, we investigate whether repeatedly fine-tuning a reward model on subsets of the offline preference dataset aligned with a periodically frozen policy during RLHF improves upon vanilla RLHF. Our empirical results demonstrate that this approach facilitates superior alignment and faster convergence compared to using an unaligned or out-of-distribution reward model relative to the LLM policy.

强化学习对齐优化奖励模型高效训练

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