When Attention Escapes: Diagnosing and Mitigating Hallucination in Retrieval-Augmented Generation

Wencheng Su, Qinglong Wang, Zhongjie Ba, Zhixuan Chu, Zhenyu Zhong, Liu Yan, Kui Ren


Abstract
Retrieval-Augmented Generation (RAG) mitigates hallucinations by grounding generation in retrieved evidence, yet failures persist when models underutilize the retrieved context. While prior work attributes this to conflicts between external context and internal parametric knowledge encoded in Feed-Forward Networks (FFNs), our empirical analyses reveal that FFN-derived signals are unstable and insufficient for reliable diagnosis across diverse contexts. We therefore propose the Attention Escape Score (AES), a training-free diagnostic framework that provides a mechanistic lens on RAG hallucinations via dynamic attention routing failures. We models the failures as weakened Semantic Anchoring, increased Contextual Distraction, and heightened Generation Inertia, moving beyond static component-level analyses. Extensive experiments show that AES significantly outperforms state-of-the-art baselines with robust cross-model generalization. Furthermore, we introduce Pruning Escape Routes (PER), a lightweight inference-time intervention that suppresses hallucinations by attenuating identified escape pathways, achieving improved faithfulness with negligible degradation to complex reasoning and general capabilities.
Anthology ID:
2026.findings-emnlp.411
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
8678–8696
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.411/
DOI:
Bibkey:
Cite (ACL):
Wencheng Su, Qinglong Wang, Zhongjie Ba, Zhixuan Chu, Zhenyu Zhong, Liu Yan, and Kui Ren. 2026. When Attention Escapes: Diagnosing and Mitigating Hallucination in Retrieval-Augmented Generation. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 8678–8696, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
When Attention Escapes: Diagnosing and Mitigating Hallucination in Retrieval-Augmented Generation (Su et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.411.pdf