arXiv:2509.14254cs.CLcs.AI2025-09被引 1

通过分析大模型内部层特征,提升幻觉检测能力。

Hallucination Detection with the Internal Layers of LLMs

  • 利用大模型内部层的动态加权融合机制进行幻觉检测。
  • 在三大评测集上表现优于传统探针方法,但跨模型泛化仍有挑战。
  • 跨基准训练和参数冻结可缓解泛化问题,适合关注模型可靠性的研究者。

大型语言模型(LLMs)在自然语言处理任务中取得了显著成功,但存在生成幻觉的缺陷——即输出看似合理却无事实依据。近期研究表明,基于探针的分类器可通过分析模型内部表示实现幻觉检测,且无需重新训练模型,计算成本低。本文提出一种新方法,利用内部层的动态加权组合来提升检测性能,并在TruthfulQA、HaluEval、ReFact三个基准上进行评估。实验表明:所提方法优于传统探针方法,但跨模型与跨基准泛化仍具挑战;通过跨基准训练和参数冻结,可有效缓解泛化问题,在单个基准上表现更好,且迁移时性能下降更小。这些发现为通过内部表示分析提升模型可靠性提供了新路径。

原文摘要 · Abstract (English)

Large Language Models (LLMs) have succeeded in a variety of natural language processing tasks [Zha+25]. However, they have notable limitations. LLMs tend to generate hallucinations, a seemingly plausible yet factually unsupported output [Hua+24], which have serious real-world consequences [Kay23; Rum+24]. Recent work has shown that probing-based classifiers that utilize LLMs' internal representations can detect hallucinations [AM23; Bei+24; Bur+24; DYT24; Ji+24; SMZ24; Su+24]. This approach, since it does not involve model training, can enhance reliability without significantly increasing computational costs. Building upon this approach, this thesis proposed novel methods for hallucination detection using LLM internal representations and evaluated them across three benchmarks: TruthfulQA, HaluEval, and ReFact. Specifically, a new architecture that dynamically weights and combines internal LLM layers was developed to improve hallucination detection performance. Throughout extensive experiments, two key findings were obtained: First, the proposed approach was shown to achieve superior performance compared to traditional probing methods, though generalization across benchmarks and LLMs remains challenging. Second, these generalization limitations were demonstrated to be mitigated through cross-benchmark training and parameter freezing. While not consistently improving, both techniques yielded better performance on individual benchmarks and reduced performance degradation when transferred to other benchmarks. These findings open new avenues for improving LLM reliability through internal representation analysis.

幻觉检测大模型内部表征

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