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Exploration-Exploitation Reshaping towards Efficient Reasoning for Large Language Models

Paper · 2026 · Yufeng Shi, Weilin Luo, Yuxiang Zhang et al.

Summary

Large Reasoning Models often overthink, producing very long chains of thought that waste compute and can introduce errors. Most RL-based fixes add length penalties to the reward. The authors argue that this only punishes long outputs after the fact, without steering the model toward shorter reasoning, and that it handles exploration and exploitation poorly.

They propose SIGMA, a GRPO-based training framework with two modules:

  • Self-imitation exploitation adds an SFT-style loss on the model's own rollouts, weighted by how much each rollout compresses the reasoning. It also replaces uniform prompt sampling with a priority table that is updated every step from per-prompt compression rates.
  • Self-guidance exploration has the model rewrite overly long rollouts, either by regenerating under a token budget or by randomly truncating them. Some original responses are kept to limit off-policy drift.

On six benchmarks with DeepSeek-R1-Distill-Qwen models, SIGMA cuts token usage substantially while matching or improving accuracy. It also gives practitioners adjustable controls for trading accuracy against efficiency.

Key points

  • On DeepSeek-R1-Distill-Qwen-1.5B and 7B, SIGMA reduces average token consumption by 43.4% and 40.3% relative to the base models, with higher accuracy.
  • Compared baselines: SFT, DPO, DAPO, AdaptThink, Laser-D, Laser-DE, JET and LCR1.
  • On Qwen3-8B, average length across six datasets falls from 7787 to 4694 tokens (−39.7%), while average accuracy moves only from 81.9% to 81.0%.
  • Ablation on dropping original responses: rewriting half of the rollouts and discarding the originals shortened outputs by 5.7% (1.5B) and 11.0% (7B). However, 7B accuracy collapsed from 72.0% to 61.6%, so keeping raw-distribution samples matters.
  • A larger self-imitation loss coefficient yields shorter outputs but lower accuracy. The 7B model's accuracy degrades less steeply than its output length shrinks.

Our summary of the paper, in our own words — not its text. The work belongs to its authors; read it at the links above.

 Institutions

 Fields, topics and concepts

Cite

Cite as Yufeng Shi, Weilin Luo, Yuxiang Zhang, Zongmeng Zhang, Haoyang Liu, Yubing Wang, Bin Wang, Wengang Zhou and Houqiang Li. 2026. Exploration-Exploitation Reshaping towards Efficient Reasoning for Large Language Models. Findings of the Association for Computational Linguistics: ACL 2026.

The paper itself, not this page. BibTeX from the library's record of the work. DOI 10.18653/v1/2026.findings-acl.1520

@inproceedings{shi2026exploration,
  title = {{Exploration-Exploitation Reshaping towards Efficient Reasoning for Large Language Models}},
  author = {Yufeng Shi, Weilin Luo, Yuxiang Zhang, Zongmeng Zhang, Haoyang Liu, Yubing Wang, Bin Wang, Wengang Zhou and Houqiang Li},
  booktitle = {Findings of the Association for Computational Linguistics: ACL 2026},
  year = {2026},
  doi = {10.18653/v1/2026.findings-acl.1520},
  url = {https://doi.org/10.18653/v1/2026.findings-acl.1520}
}

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