Explaining multimodal LLMs via intra-modal token interactions

Fuente: arXiv
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Auteurs principaux: Liang, Jiawei, Chen, Ruoyu, Jiao, Xianghao, Liang, Siyuan, Liu, Shiming, Zhang, Qunli, Hu, Zheng, Cao, Xiaochun
Format: Preprint
Publié: 2025
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author Liang, Jiawei
Chen, Ruoyu
Jiao, Xianghao
Liang, Siyuan
Liu, Shiming
Zhang, Qunli
Hu, Zheng
Cao, Xiaochun
author_facet Liang, Jiawei
Chen, Ruoyu
Jiao, Xianghao
Liang, Siyuan
Liu, Shiming
Zhang, Qunli
Hu, Zheng
Cao, Xiaochun
contents Multimodal Large Language Models (MLLMs) have achieved remarkable success across diverse vision-language tasks, yet their internal decision-making mechanisms remain insufficiently understood. Existing interpretability research has primarily focused on cross-modal attribution, identifying which image regions the model attends to during output generation. However, these approaches often overlook intra-modal dependencies. In the visual modality, attributing importance to isolated image patches ignores spatial context due to limited receptive fields, resulting in fragmented and noisy explanations. In the textual modality, reliance on preceding tokens introduces spurious activations. Failing to effectively mitigate these interference compromises attribution fidelity. To address these limitations, we propose enhancing interpretability by leveraging intra-modal interaction. For the visual branch, we introduce \textit{Multi-Scale Explanation Aggregation} (MSEA), which aggregates attributions over multi-scale inputs to dynamically adjust receptive fields, producing more holistic and spatially coherent visual explanations. For the textual branch, we propose \textit{Activation Ranking Correlation} (ARC), which measures the relevance of contextual tokens to the current token via alignment of their top-$k$ prediction rankings. ARC leverages this relevance to suppress spurious activations from irrelevant contexts while preserving semantically coherent ones. Extensive experiments across state-of-the-art MLLMs and benchmark datasets demonstrate that our approach consistently outperforms existing interpretability methods, yielding more faithful and fine-grained explanations of model behavior.
format Preprint
id arxiv_https___arxiv_org_abs_2509_22415
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Explaining multimodal LLMs via intra-modal token interactions
Liang, Jiawei
Chen, Ruoyu
Jiao, Xianghao
Liang, Siyuan
Liu, Shiming
Zhang, Qunli
Hu, Zheng
Cao, Xiaochun
Computer Vision and Pattern Recognition
Artificial Intelligence
Multimodal Large Language Models (MLLMs) have achieved remarkable success across diverse vision-language tasks, yet their internal decision-making mechanisms remain insufficiently understood. Existing interpretability research has primarily focused on cross-modal attribution, identifying which image regions the model attends to during output generation. However, these approaches often overlook intra-modal dependencies. In the visual modality, attributing importance to isolated image patches ignores spatial context due to limited receptive fields, resulting in fragmented and noisy explanations. In the textual modality, reliance on preceding tokens introduces spurious activations. Failing to effectively mitigate these interference compromises attribution fidelity. To address these limitations, we propose enhancing interpretability by leveraging intra-modal interaction. For the visual branch, we introduce \textit{Multi-Scale Explanation Aggregation} (MSEA), which aggregates attributions over multi-scale inputs to dynamically adjust receptive fields, producing more holistic and spatially coherent visual explanations. For the textual branch, we propose \textit{Activation Ranking Correlation} (ARC), which measures the relevance of contextual tokens to the current token via alignment of their top-$k$ prediction rankings. ARC leverages this relevance to suppress spurious activations from irrelevant contexts while preserving semantically coherent ones. Extensive experiments across state-of-the-art MLLMs and benchmark datasets demonstrate that our approach consistently outperforms existing interpretability methods, yielding more faithful and fine-grained explanations of model behavior.
title Explaining multimodal LLMs via intra-modal token interactions
topic Computer Vision and Pattern Recognition
Artificial Intelligence
url https://arxiv.org/abs/2509.22415