Mitigating Hallucinations in Large Language Models Via Decoder Layer Skipping

Fuente: arXiv
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Autores principales: Li, Hanze, You, Jinhao, Guo, Yichen, Tang, Kai, Xie, Shuangyang, Huang, Xiande
Formato: Preprint
Publicado: 2026
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author Li, Hanze
You, Jinhao
Guo, Yichen
Tang, Kai
Xie, Shuangyang
Huang, Xiande
author_facet Li, Hanze
You, Jinhao
Guo, Yichen
Tang, Kai
Xie, Shuangyang
Huang, Xiande
contents Large Language Models (LLMs) have achieved strong performance across diverse natural language tasks, yet their outputs often suffer from hallucinations -- content that is misaligned with factual information. In this work, we conduct a comprehensive layer-wise analysis of the decoding process and reveal that hallucinations tend to originate from deeper decoder layers. To address this issue, we introduce \textbf{DeLask} (\textbf{De}coder \textbf{La}yer \textbf{Sk}ipping), a novel decoding framework that dynamically skips layers prone to producing hallucinations. DeLask leverages the theoretical insight that the forward computation of an $L$-layer Transformer is conditionally equivalent to $L$ steps of gradient descent. We define a \emph{driftance value} by computing the cosine similarity between gradients derived from consecutive decoder steps, identifying problematic layers when the descent direction reverses. Rather than discarding such layers entirely, DeLask partially aggregates their hidden states with preceding layers, thereby preserving consistency while suppressing erroneous signals. Extensive experiments across diverse LLMs and benchmarks demonstrate that DeLask consistently mitigates hallucinations and enhances overall reliability, providing a lightweight and generalizable decoding framework for improving the robustness of large-scale language models.
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id arxiv_https___arxiv_org_abs_2606_00819
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Mitigating Hallucinations in Large Language Models Via Decoder Layer Skipping
Li, Hanze
You, Jinhao
Guo, Yichen
Tang, Kai
Xie, Shuangyang
Huang, Xiande
Artificial Intelligence
Large Language Models (LLMs) have achieved strong performance across diverse natural language tasks, yet their outputs often suffer from hallucinations -- content that is misaligned with factual information. In this work, we conduct a comprehensive layer-wise analysis of the decoding process and reveal that hallucinations tend to originate from deeper decoder layers. To address this issue, we introduce \textbf{DeLask} (\textbf{De}coder \textbf{La}yer \textbf{Sk}ipping), a novel decoding framework that dynamically skips layers prone to producing hallucinations. DeLask leverages the theoretical insight that the forward computation of an $L$-layer Transformer is conditionally equivalent to $L$ steps of gradient descent. We define a \emph{driftance value} by computing the cosine similarity between gradients derived from consecutive decoder steps, identifying problematic layers when the descent direction reverses. Rather than discarding such layers entirely, DeLask partially aggregates their hidden states with preceding layers, thereby preserving consistency while suppressing erroneous signals. Extensive experiments across diverse LLMs and benchmarks demonstrate that DeLask consistently mitigates hallucinations and enhances overall reliability, providing a lightweight and generalizable decoding framework for improving the robustness of large-scale language models.
title Mitigating Hallucinations in Large Language Models Via Decoder Layer Skipping
topic Artificial Intelligence
url https://arxiv.org/abs/2606.00819