自适应调整训练目标,防止大模型自评估时崩溃
A Rolling Stone Gathers No Moss: Adaptive Policy Optimization for Stable Self-Evaluation in Large Multimodal Models
- 根据任务进展动态调整奖励机制,避免奖励欺骗
- 在8个基准上提升推理与自评能力,效果显著
- 无需人工干预,自动聚焦不同子任务的训练进度
自评估是大模型在多轮对话中实现自我改进的关键,但现有基础模型普遍缺乏此能力。虽有研究采用强化学习提升自评估,但固定奖励机制在优化多个目标时易引发奖励欺骗,导致模型崩溃。本文提出AdaPO,一种在线强化学习框架,可依据当前训练状态实时自适应调整各任务的训练目标。为缓解奖励欺骗,AdaPO引入自适应奖励模型(ARM)和基于奖励差距的动态KL正则化机制。ARM通过分析模型生成多轮轨迹的性能分布来评估任务训练状态;动态KL正则化以奖励差距调节惩罚系数,取代固定惩罚。方法能自动平滑地调整学习重点,无需人工干预。在8个基准和多种模型上的实验证明,该方法显著提升了直接推理与自评估能力。代码将开源以促进社区发展。
原文摘要 · Abstract (English)
Self-evaluation, a model's ability to assess the correctness of its own output, is crucial for Large Multimodal Models (LMMs) to achieve self-improvement in multi-turn conversations, yet largely absent in foundation models. Recent work has employed reinforcement learning (RL) to enhance self-evaluation; however, its fixed reward mechanism suffers from reward hacking when optimizing multiple training objectives, leading to model collapse. In this paper we propose AdaPO, an online reinforcement learning framework capable of adaptively adjusting training objective in real time according to the current training state for each task. Specifically, to mitigate reward hacking , AdaPO introduces an Adaptive Reward Model (ARM) and a Reward Aware Dynamic KL Regularization mechanism. ARM assesses the task's training state from the distribution of model generated multi-turn trajectories' performance. Reward Aware Dynamic KL replaces a fixed penalty with dynamic coefficients which is modulated by the reward gap between different multi-turn situations. Notably, our method automatically and smoothly adjusts its learning focus based on sub-tasks' training progress without manual intervention. Extensive experiments over 8 benchmarks and various models show that our method significantly enhances both direct reasoning and self-evaluation capability. We will release our code to contribute to the community.
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