CRAM: Centroid-Routing and Adaptive MoE for Multimodal Continual Instruction Tuning

Jun-Tao Tang, Zhen-Hao Xie, Yu-Cheng Shi, Da-Wei Zhou


Abstract
Multimodal Large Language Models (MLLMs) unify heterogeneous vision-language tasks under a shared generative framework via instruction tuning, yet real-world deployment demands continuous capability expansion, making Multimodal Continual Instruction Tuning (MCIT) essential. Existing methods either update all tasks with a shared parameter set or allocate dedicated modules for each new task. Shared updates force heterogeneous tasks to compete, causing forgetting of learned capabilities. Conversely, isolated expansion prevents interference but severely limits parameter efficiency over long task streams. To address this dilemma, we propose CRAM (Centroid-Routing and Adaptive MoE). Specifically, by isolating task-specific patterns into independent modules, CRAM mitigates catastrophic forgetting across tasks. To further boost parameter efficiency, we utilize adaptive-rank instantiation to identify the capability gap between existing expert capability and new task demands, and dynamically allocate only the necessary parameters. To ensure stable reuse among tasks, centroid-guided routing recognizes and activates existing experts’ capabilities, while an orthogonality penalty confines new updates to task-specific directions, preventing re-learning general capability. Extensive experiments across diverse benchmarks demonstrate its superiority over existing methods. Code is available at https://github.com/LAMDA-CL/EMNLP2026-CRAM.
Anthology ID:
2026.emnlp-main.1175
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
26936–26953
Language:
URL:
https://aclanthology.org/2026.emnlp-main.1175/
DOI:
Bibkey:
Cite (ACL):
Jun-Tao Tang, Zhen-Hao Xie, Yu-Cheng Shi, and Da-Wei Zhou. 2026. CRAM: Centroid-Routing and Adaptive MoE for Multimodal Continual Instruction Tuning. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 26936–26953, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
CRAM: Centroid-Routing and Adaptive MoE for Multimodal Continual Instruction Tuning (Tang et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.1175.pdf