Detecting Hallucinations in Graph Retrieval-Augmented Generation via Attention Patterns and Semantic Alignment

Fuente: arXiv
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Autori principali: Li, Shanghao, Han, Jinda, Wang, Yibo, Zhu, Yuanjie, Song, Zihe, He, Langzhou, Alghythee, Kenan Kamel A, Yu, Philip S.
Natura: Preprint
Pubblicazione: 2025
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author Li, Shanghao
Han, Jinda
Wang, Yibo
Zhu, Yuanjie
Song, Zihe
He, Langzhou
Alghythee, Kenan Kamel A
Yu, Philip S.
author_facet Li, Shanghao
Han, Jinda
Wang, Yibo
Zhu, Yuanjie
Song, Zihe
He, Langzhou
Alghythee, Kenan Kamel A
Yu, Philip S.
contents Graph-based Retrieval-Augmented Generation (GraphRAG) enhances Large Language Models (LLMs) by incorporating external knowledge from linearized subgraphs retrieved from knowledge graphs. However, LLMs struggle to interpret the relational and topological information in these inputs, resulting in hallucinations that are inconsistent with the retrieved knowledge. To analyze how LLMs attend to and retain structured knowledge during generation, we propose two lightweight interpretability metrics: Path Reliance Degree (PRD), which measures over-reliance on shortest-path triples, and Semantic Alignment Score (SAS), which assesses how well the model's internal representations align with the retrieved knowledge. Through empirical analysis on a knowledge-based QA task, we identify failure patterns associated with over-reliance on salient paths and weak semantic grounding, as indicated by high PRD and low SAS scores. We further develop a lightweight post-hoc hallucination detector, Graph Grounding and Alignment (GGA), which outperforms strong semantic and confidence-based baselines across AUC and F1. By grounding hallucination analysis in mechanistic interpretability, our work offers insights into how structural limitations in LLMs contribute to hallucinations, informing the design of more reliable GraphRAG systems in the future.
format Preprint
id arxiv_https___arxiv_org_abs_2512_09148
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Detecting Hallucinations in Graph Retrieval-Augmented Generation via Attention Patterns and Semantic Alignment
Li, Shanghao
Han, Jinda
Wang, Yibo
Zhu, Yuanjie
Song, Zihe
He, Langzhou
Alghythee, Kenan Kamel A
Yu, Philip S.
Computation and Language
Artificial Intelligence
I.2.7
Graph-based Retrieval-Augmented Generation (GraphRAG) enhances Large Language Models (LLMs) by incorporating external knowledge from linearized subgraphs retrieved from knowledge graphs. However, LLMs struggle to interpret the relational and topological information in these inputs, resulting in hallucinations that are inconsistent with the retrieved knowledge. To analyze how LLMs attend to and retain structured knowledge during generation, we propose two lightweight interpretability metrics: Path Reliance Degree (PRD), which measures over-reliance on shortest-path triples, and Semantic Alignment Score (SAS), which assesses how well the model's internal representations align with the retrieved knowledge. Through empirical analysis on a knowledge-based QA task, we identify failure patterns associated with over-reliance on salient paths and weak semantic grounding, as indicated by high PRD and low SAS scores. We further develop a lightweight post-hoc hallucination detector, Graph Grounding and Alignment (GGA), which outperforms strong semantic and confidence-based baselines across AUC and F1. By grounding hallucination analysis in mechanistic interpretability, our work offers insights into how structural limitations in LLMs contribute to hallucinations, informing the design of more reliable GraphRAG systems in the future.
title Detecting Hallucinations in Graph Retrieval-Augmented Generation via Attention Patterns and Semantic Alignment
topic Computation and Language
Artificial Intelligence
I.2.7
url https://arxiv.org/abs/2512.09148