人类对模型能力的信念影响偏好判断,调整信念可提升强化学习效果。
A Descriptive and Normative Theory of Human Beliefs in RLHF
- 引入人类信念作为偏好建模的新因素,突破传统奖励函数视角。
- 实验表明信念偏差会显著影响人工标注,干预可有效改变信念。
- 提出理想信念理论框架,指导实践中如何减少信念错配。
在强化学习中的人类反馈(RLHF)中,人类偏好通常被建模为人类奖励函数或最优状态-动作值的函数。本文提出,人类对训练中智能体能力的认知也对偏好生成起关键作用。我们围绕这一假设提出两个问题:人类对智能体能力的信念是否影响其提供的偏好?理想的信念体系应是什么?我们提出一种融合人类信念的新偏好模型,并建立规范性理论,基于人类信念与理想信念之间的不匹配程度,界定了最终学习策略的误差上限。通过人类实验验证,信念确实显著影响偏好,且可通过简单干预改变。此外,合成实验表明,假设智能体最优往往并非最优策略。结果从理论和实证上表明,缩小人类信念与智能体实际能力间的差距,可提升RLHF性能,为从业者提供新实践准则。
原文摘要 · Abstract (English)
Human preferences in RLHF are typically modeled as a function of the human's reward function or corresponding optimal state-action values. In this work, we propose that human beliefs about the capabilities of the agent being trained also play a key role in preference generation. We examine two questions related to this hypothesis, one descriptive and one normative, respectively: Do human labelers' beliefs about agent capabilities affect the preferences that they provide? And what is the ideal set of beliefs about an agent -- and resulting preferences -- for humans to have? We propose a new preference model that incorporates human beliefs and provide a normative theory that bounds the error on the final learned policy based on the mismatch between the human's beliefs and an idealized set of beliefs. We then confirm via a human study that beliefs about agent capabilities do, in fact, significantly affect preferences and can be influenced through simple interventions. Additionally, we empirically show through synthetic experiments that it is often suboptimal for human preference labelers to assume agent optimality. Collectively, these results theoretically and empirically demonstrate how reducing the mismatch between human beliefs and agent capabilities can lead to more performant RLHF and point toward new best practices for RLHF practitioners.
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