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arXiv 2602.02427cs.LG

嵌入扰动可能更好地反映大语言模型推理中的中间步骤不确定性

Uncertainty Localization in LLM Reasoning via Embedding Perturbations

University of Arizona(亚利桑那大学);Michigan State University(密歇根州立大学)

Qihao Wen, Jiahao Wang, Yang Nan, Pengfei He, Ravi Tandon, Han Xu

AI总结:

本文研究了大语言模型推理中中间步骤不确定性的量化方法,发现基于嵌入扰动的指标在不确定性评估中表现更优,具有更高的效率和简洁性。

摘要:

大型语言模型(LLMs)在多个领域取得了显著进展;然而,它们仍可能产生不可靠或误导性的输出。为了负责任地应用LLMs,不确定性量化(UQ)技术用于估计模型对其输出的不确定性,表明这些输出可能存在问题的可能性。对于LLMs推理任务,估计最终答案和推理中间步骤的不确定性至关重要,因为这可以实现更精细和有针对性的干预。在本研究中,我们探讨了哪些UQ指标更能反映LLMs在推理过程中的“中间不确定性”。我们的研究发现,LLMs的错误推理步骤通常包含对前一token嵌入扰动高度敏感的token,表明模型在多个竞争延续之间存在不确定性。通过这种敏感度分数,可以方便地在实践中识别不确定(可能错误)的中间步骤。在我们的实验中,我们展示了基于扰动的指标在不确定性量化性能上优于概率、采样和贝叶斯方法,同时具有良好的简洁性和效率。

英文摘要:

Large Language Models (LLMs) have achieved significant breakthroughs across various domains, but they can still produce unreliable or misleading outputs. For responsible LLM applications, uncertainty quantification techniques are used to estimate a model's uncertainty about its outputs, indicating the likelihood that those outputs may be problematic. For LLM reasoning tasks, it is essential to estimate uncertainty not only in the final answer but also in the intermediate reasoning process, particularly to identify where uncertainty arises. Such information may enable more fine-grained and targeted interventions during inference. In this study, we investigate which metrics can effectively localize uncertain places within an LLM reasoning trajectory. Our study reveals that uncertain intermediate continuations are more likely to occur at tokens that are highly sensitive to perturbations in the embeddings of preceding tokens. In our experiments, we show that such perturbation-based metrics achieve stronger performance in localizing uncertain intermediate steps than baseline methods, including probability-based, sampling-based, and Bayesian-based approaches. Meanwhile, our proposed metrics also enjoy good simplicity and efficiency.

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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