用文本反馈提升强化学习,让模型学会自我改进。
Expanding the Capabilities of Reinforcement Learning via Text Feedback
- 引入多轮文本反馈机制,让模型从人类点评中学习
- 在推理题、数学竞赛和创意写作上均超越现有基线
- 适合希望低成本提升大模型生成质量的研究者
强化学习在大语言模型后训练中的成功,依赖于每轮仅一个比特的信息:二元奖励或偏好标签。而知识蒸馏虽提供密集监督,却需昂贵且难扩展的示范数据。本文研究文本反馈作为中间信号:比标量奖励更丰富,又比完整示范更廉价。文本反馈是人机交互的自然形式,在实际场景中已大量存在,如用户、标注员和自动评判者常对LLM输出进行批评。为实现文本反馈的大规模应用,我们提出多轮强化学习框架——从文本反馈中学习(RLTF),其中文本反馈仅用于训练,不用于推理。因此,模型必须学会内化反馈以提升测试时单轮表现。我们提出两种方法:自蒸馏(RLTF-SD),使单轮策略匹配自身反馈条件下的第二轮生成;反馈建模(RLTF-FM),将预测反馈作为辅助目标。我们提供了理论分析,并在推理谜题、竞赛数学和创意写作任务上进行了实证评估。结果表明,两种方法在多个基准上均持续优于强基线,凸显了大规模使用丰富监督信号的潜力。
原文摘要 · Abstract (English)
The success of RL for LLM post-training stems from an unreasonably uninformative source: a single bit of information per rollout as binary reward or preference label. At the other extreme, distillation offers dense supervision but requires demonstrations, which are costly and difficult to scale. We study text feedback as an intermediate signal: richer than scalar rewards, yet cheaper than complete demonstrations. Textual feedback is a natural mode of human interaction and is already abundant in many real-world settings, where users, annotators, and automated judges routinely critique LLM outputs. Towards leveraging text feedback at scale, we formalize a multi-turn RL setup, RL from Text Feedback (RLTF), where text feedback is available during training but not at inference. Therefore, models must learn to internalize the feedback in order to improve their test-time single-turn performance. To do this, we propose two methods: Self Distillation (RLTF-SD), which trains the single-turn policy to match its own feedback-conditioned second-turn generations; and Feedback Modeling (RLTF-FM), which predicts the feedback as an auxiliary objective. We provide theoretical analysis on both methods, and empirically evaluate on reasoning puzzles, competition math, and creative writing tasks. Our results show that both methods consistently outperform strong baselines across benchmarks, highlighting the potential of RL with an additional source of rich supervision at scale.
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