arXivDaily arXiv每日学术速递 周一至周五更新
arXiv 2602.02495cs.CLcs.AIcs.LG

无奖励的冲突目标对齐

Reward-free Alignment for Conflicting Objectives

Columbia University(哥伦比亚大学)

Peter Chen, Xiaopeng Li, Xi Chen, Tianyi Lin

AI总结:

提出RACO框架,通过冲突规避梯度下降的裁剪变体直接利用成对偏好数据解决多目标冲突,实现帕累托最优对齐。

摘要:

直接对齐方法越来越多地用于将大型语言模型(LLMs)与人类偏好对齐。然而,许多现实世界的对齐问题涉及多个相互冲突的目标,简单的偏好聚合可能导致训练不稳定和糟糕的权衡。特别是,加权损失方法可能无法识别同时改善所有目标的更新方向,而现有的多目标方法通常依赖显式奖励模型,增加了额外复杂性并扭曲了用户指定的偏好。本文的贡献有两方面。首先,我们提出了一种用于冲突目标的无奖励对齐框架(RACO),该框架直接利用成对偏好数据,并通过一种新颖的冲突规避梯度下降的裁剪变体解决梯度冲突。我们提供了收敛到尊重用户指定目标权重的帕累托临界点的保证,并进一步证明在双目标设置中裁剪可以严格改善收敛速度。其次,我们使用一些启发式方法改进了我们的方法,并进行了实验,以证明所提框架在LLM对齐中的兼容性。在多个LLM家族(Qwen 3、Llama 3、Gemma 3)上的多目标摘要和安全对齐任务的定性和定量评估表明,与现有的多目标对齐基线相比,我们的方法始终能实现更好的帕累托权衡。

英文摘要:

Direct alignment methods are increasingly used to align large language models (LLMs) with human preferences. However, many real-world alignment problems involve multiple conflicting objectives, where naive aggregation of preferences can lead to unstable training and poor trade-offs. In particular, weighted loss methods may fail to identify update directions that simultaneously improve all objectives, and existing multi-objective approaches often rely on explicit reward models, introducing additional complexity and distorting user-specified preferences. The contributions of this paper are two-fold. First, we propose a Reward-free Alignment framework for Conflicted Objectives (RACO) that directly leverages pairwise preference data and resolves gradient conflicts via a novel clipped variant of conflict-averse gradient descent. We provide convergence guarantees to Pareto-critical points that respect user-specified objective weights, and further show that clipping can strictly improve convergence rate in the two-objective setting. Second, we improve our method using some heuristics and conduct experiments to demonstrate the compatibility of the proposed framework for LLM alignment. Both qualitative and quantitative evaluations on multi-objective summarization and safety alignment tasks across multiple LLM families (Qwen 3, Llama 3, Gemma 3) show that our method consistently achieves better Pareto trade-offs compared to existing multi-objective alignment baselines.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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