Sustaining Cross-Modal Dependency for Generalizable Vision-Language Model Tuning

Chenhao Ding, Jizhou Han, SongLin Dong, Xinyuan Gao, Qiang Wang, Lixin Xiu, Wei Ke, Yihong Gong, Hideki Nakayama


Abstract
Recent parameter-efficient fine-tuning (PEFT) methods effectively adapt Vision-Language Models (VLMs) to seen tasks, yet often exhibit limited generalization to unseen novel classes. To better understand this phenomenon, we analyze adaptation dynamics from the perspective of cross-modal mutual information (MI). Our empirical analyses reveal a consistent pattern across existing methods: during the adaptation process, cross-modal MI for novel classes frequently encounters early plateaus or declines, indicating weakened cross-modal semantic dependency. Motivated by this observation, we propose Retrieval-Augmented Dynamic Adaptation (RADA), a retrieval-enhanced adaptation framework that continuously injects rich instance-specific semantic priors through an LLM-enhanced dual-modality memory bank and a lightweight modality-agnostic token generator. By facilitating fine-grained cross-modal alignment while preserving pretrained zero-shot ability, RADA achieves more transferable adaptation across diverse scenarios. Extensive experiments across multiple widely used benchmarks demonstrate that RADA consistently achieves state-of-the-art performance while maintaining strong zero-shot capability. In addition, our empirical analyses show that RADA preserves more stable cross-modal dependency trajectories throughout adaptation, offering further insights into the relationship between adaptation dynamics and generalization in VLMs.
Anthology ID:
2026.findings-emnlp.192
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:
4067–4095
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.192/
DOI:
Bibkey:
Cite (ACL):
Chenhao Ding, Jizhou Han, SongLin Dong, Xinyuan Gao, Qiang Wang, Lixin Xiu, Wei Ke, Yihong Gong, and Hideki Nakayama. 2026. Sustaining Cross-Modal Dependency for Generalizable Vision-Language Model Tuning. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 4067–4095, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Sustaining Cross-Modal Dependency for Generalizable Vision-Language Model Tuning (Ding et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.192.pdf