Separate First, Fuse Later: Mitigating Cross-Modal Interference in Audio-Visual LLMs Reasoning with Modality-Specific Chain-of-Thought

Fuente: arXiv
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Main Authors: Li, Xuanchen, Lu, Yuheng, Cui, Chenrui, Wang, Tianrui, Huang, Zikang, Jiang, Yu, Zhou, Long, Wang, Longbiao, Dang, Jianwu
Format: Preprint
Published: 2026
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author Li, Xuanchen
Lu, Yuheng
Cui, Chenrui
Wang, Tianrui
Huang, Zikang
Jiang, Yu
Zhou, Long
Wang, Longbiao
Dang, Jianwu
author_facet Li, Xuanchen
Lu, Yuheng
Cui, Chenrui
Wang, Tianrui
Huang, Zikang
Jiang, Yu
Zhou, Long
Wang, Longbiao
Dang, Jianwu
contents Audio and vision provide complementary evidence for audio-visual question answering, yet current audio-visual large language models may suffer from cross-modal interference: information from one modality misguides the interpretation of another, thereby inducing hallucinations. We attribute this issue to uncontrolled cross-modal interactions during intermediate reasoning. To mitigate this, we propose Separate First, Fuse Later (SFFL), an audio-visual reasoning framework designed to reduce cross-modal interference. SFFL enforces modality-specific chain-of-thought reasoning, producing separate audio and visual reasoning traces and integrating evidence for answering. We construct modality-preference labels via a data pipeline under different modality input settings. We use these labels as an auxiliary reward in reinforcement learning to encourage a instance-dependent preference for modality cues when answering. We further introduce a modality-specific reasoning mechanism that preserves modality isolation during the separated reasoning stage while enabling full access to cross-modal information at the evidence fusion stage. Experiments demonstrate consistent improvements in both accuracy and robustness, yielding an average relative gain of 5.16\% on general AVQA benchmarks and 11.17\% on a cross-modal hallucination benchmark.
format Preprint
id arxiv_https___arxiv_org_abs_2605_09906
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Separate First, Fuse Later: Mitigating Cross-Modal Interference in Audio-Visual LLMs Reasoning with Modality-Specific Chain-of-Thought
Li, Xuanchen
Lu, Yuheng
Cui, Chenrui
Wang, Tianrui
Huang, Zikang
Jiang, Yu
Zhou, Long
Wang, Longbiao
Dang, Jianwu
Artificial Intelligence
Sound
Audio and vision provide complementary evidence for audio-visual question answering, yet current audio-visual large language models may suffer from cross-modal interference: information from one modality misguides the interpretation of another, thereby inducing hallucinations. We attribute this issue to uncontrolled cross-modal interactions during intermediate reasoning. To mitigate this, we propose Separate First, Fuse Later (SFFL), an audio-visual reasoning framework designed to reduce cross-modal interference. SFFL enforces modality-specific chain-of-thought reasoning, producing separate audio and visual reasoning traces and integrating evidence for answering. We construct modality-preference labels via a data pipeline under different modality input settings. We use these labels as an auxiliary reward in reinforcement learning to encourage a instance-dependent preference for modality cues when answering. We further introduce a modality-specific reasoning mechanism that preserves modality isolation during the separated reasoning stage while enabling full access to cross-modal information at the evidence fusion stage. Experiments demonstrate consistent improvements in both accuracy and robustness, yielding an average relative gain of 5.16\% on general AVQA benchmarks and 11.17\% on a cross-modal hallucination benchmark.
title Separate First, Fuse Later: Mitigating Cross-Modal Interference in Audio-Visual LLMs Reasoning with Modality-Specific Chain-of-Thought
topic Artificial Intelligence
Sound
url https://arxiv.org/abs/2605.09906