Monkey Jump: MoE-Style PEFT for Efficient Multi-Task Learning

Nusrat Jahan Prottasha, Md Kowsher, Chun-Nam Yu, Chen Chen, Ozlem Garibay


Abstract
Mixture-of-experts variants of parameter-efficient fine-tuning enable per-token specialization, but they introduce additional trainable routers and expert parameters, increasing memory and training costs. This undermines the core goal of parameter efficient finetuning. We propose Monkey Jump, which brings MoE-style specialization to PEFT without adding extra trainable parameters for experts and routers. Instead of introducing new PEFT adapters as experts, Monkey Jump treats the PEFT adapters already present in each Transformer block (e.g., query, key, value, up, and down projections) as implicit experts and routes tokens among them. Routing is performed via k-means clustering with EMA-updated centers—no gradients, no learned parameters. We theoretically show that token-wise routing increases expressivity and can outperform shared adapters by avoiding cancellation effects. In multi-task experiments spanning 14 text, 14 image, and 19 video benchmarks, Monkey Jump achieves competitive performance with MoE-PEFT methods while using 5.3–9.2× fewer trainable parameters than the MoE variant of the same base method, up to 48% lower memory, and 1.5–2× faster training. Monkey Jump is architecture-agnostic and can be applied to any adapter-based PEFT method.
Anthology ID:
2026.emnlp-main.801
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:
18631–18674
Language:
URL:
https://aclanthology.org/2026.emnlp-main.801/
DOI:
Bibkey:
Cite (ACL):
Nusrat Jahan Prottasha, Md Kowsher, Chun-Nam Yu, Chen Chen, and Ozlem Garibay. 2026. Monkey Jump: MoE-Style PEFT for Efficient Multi-Task Learning. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 18631–18674, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Monkey Jump: MoE-Style PEFT for Efficient Multi-Task Learning (Prottasha et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.801.pdf