PruneCD: Contrasting Pruned Self Model to Improve Decoding Factuality

Fuente: arXiv
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Hauptverfasser: Yu, Byeongho, Lee, Changhun, Jin, Jungyu, Park, Eunhyeok
Format: Preprint
Veröffentlicht: 2025
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author Yu, Byeongho
Lee, Changhun
Jin, Jungyu
Park, Eunhyeok
author_facet Yu, Byeongho
Lee, Changhun
Jin, Jungyu
Park, Eunhyeok
contents To mitigate the hallucination problem in large language models, DoLa exploits early exit logits from the same model as a contrastive prior. However, we found that these early exit logits tend to be flat, low in magnitude, and fail to reflect meaningful contrasts. To address this, we propose PruneCD, a novel contrastive decoding method that constructs the amateur model via layer pruning rather than early exit. This design leads to more informative and well-aligned logits, enabling more effective contrastive decoding. Through qualitative and quantitative analyses, we demonstrate that PruneCD consistently improves factuality with minimal inference overhead, offering a robust and practical approach to mitigating hallucinations in LLMs.
format Preprint
id arxiv_https___arxiv_org_abs_2509_16598
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle PruneCD: Contrasting Pruned Self Model to Improve Decoding Factuality
Yu, Byeongho
Lee, Changhun
Jin, Jungyu
Park, Eunhyeok
Computation and Language
Artificial Intelligence
To mitigate the hallucination problem in large language models, DoLa exploits early exit logits from the same model as a contrastive prior. However, we found that these early exit logits tend to be flat, low in magnitude, and fail to reflect meaningful contrasts. To address this, we propose PruneCD, a novel contrastive decoding method that constructs the amateur model via layer pruning rather than early exit. This design leads to more informative and well-aligned logits, enabling more effective contrastive decoding. Through qualitative and quantitative analyses, we demonstrate that PruneCD consistently improves factuality with minimal inference overhead, offering a robust and practical approach to mitigating hallucinations in LLMs.
title PruneCD: Contrasting Pruned Self Model to Improve Decoding Factuality
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2509.16598