Text-Guided Layer Fusion Mitigates Hallucination in Multimodal LLMs

Fuente: arXiv
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Main Authors: Lin, Chenchen, Su, Sanbao, Luo, Rachel, Chen, Yuxiao, Wang, Yan, Pavone, Marco, Miao, Fei
Format: Preprint
Published: 2026
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author Lin, Chenchen
Su, Sanbao
Luo, Rachel
Chen, Yuxiao
Wang, Yan
Pavone, Marco
Miao, Fei
author_facet Lin, Chenchen
Su, Sanbao
Luo, Rachel
Chen, Yuxiao
Wang, Yan
Pavone, Marco
Miao, Fei
contents Multimodal large language models (MLLMs) typically rely on a single late-layer feature from a frozen vision encoder, leaving the encoder's rich hierarchy of visual cues under-utilized. MLLMs still suffer from visually ungrounded hallucinations, often relying on language priors rather than image evidence. While many prior mitigation strategies operate on the text side, they leave the visual representation unchanged and do not exploit the rich hierarchy of features encoded across vision layers. Existing multi-layer fusion methods partially address this limitation but remain static, applying the same layer mixture regardless of the query. In this work, we introduce TGIF (Text-Guided Inter-layer Fusion), a lightweight module that treats encoder layers as depth-wise "experts" and predicts a prompt-dependent fusion of visual features. TGIF follows the principle of direct external fusion, requires no vision-encoder updates, and adds minimal overhead. Integrated into LLaVA-1.5-7B, TGIF provides consistent improvements across hallucination, OCR, and VQA benchmarks, while preserving or improving performance on ScienceQA, GQA, and MMBench. These results suggest that query-conditioned, hierarchy-aware fusion is an effective way to strengthen visual grounding and reduce hallucination in modern MLLMs.
format Preprint
id arxiv_https___arxiv_org_abs_2601_03100
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Text-Guided Layer Fusion Mitigates Hallucination in Multimodal LLMs
Lin, Chenchen
Su, Sanbao
Luo, Rachel
Chen, Yuxiao
Wang, Yan
Pavone, Marco
Miao, Fei
Computer Vision and Pattern Recognition
Artificial Intelligence
Multimodal large language models (MLLMs) typically rely on a single late-layer feature from a frozen vision encoder, leaving the encoder's rich hierarchy of visual cues under-utilized. MLLMs still suffer from visually ungrounded hallucinations, often relying on language priors rather than image evidence. While many prior mitigation strategies operate on the text side, they leave the visual representation unchanged and do not exploit the rich hierarchy of features encoded across vision layers. Existing multi-layer fusion methods partially address this limitation but remain static, applying the same layer mixture regardless of the query. In this work, we introduce TGIF (Text-Guided Inter-layer Fusion), a lightweight module that treats encoder layers as depth-wise "experts" and predicts a prompt-dependent fusion of visual features. TGIF follows the principle of direct external fusion, requires no vision-encoder updates, and adds minimal overhead. Integrated into LLaVA-1.5-7B, TGIF provides consistent improvements across hallucination, OCR, and VQA benchmarks, while preserving or improving performance on ScienceQA, GQA, and MMBench. These results suggest that query-conditioned, hierarchy-aware fusion is an effective way to strengthen visual grounding and reduce hallucination in modern MLLMs.
title Text-Guided Layer Fusion Mitigates Hallucination in Multimodal LLMs
topic Computer Vision and Pattern Recognition
Artificial Intelligence
url https://arxiv.org/abs/2601.03100