Merge-of-Thought Distillation

Fuente: arXiv
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Main Authors: Shen, Zhanming, Qin, Zeyu, Huang, Zenan, Chen, Hao, Hu, Jiaqi, Zhuang, Yihong, Lu, Guoshan, Chen, Gang, Zhao, Junbo
Format: Preprint
Published: 2025
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_version_ 1866909850010648576
author Shen, Zhanming
Qin, Zeyu
Huang, Zenan
Chen, Hao
Hu, Jiaqi
Zhuang, Yihong
Lu, Guoshan
Chen, Gang
Zhao, Junbo
author_facet Shen, Zhanming
Qin, Zeyu
Huang, Zenan
Chen, Hao
Hu, Jiaqi
Zhuang, Yihong
Lu, Guoshan
Chen, Gang
Zhao, Junbo
contents Efficient reasoning distillation for long chain-of-thought (CoT) models is increasingly constrained by the assumption of a single oracle teacher, despite the practical availability of multiple candidate teachers and growing CoT corpora. We revisit teacher selection and observe that different students have different "best teachers," and even for the same student, the best teacher can vary across datasets. Therefore, to unify multiple teachers' reasoning abilities into a student to overcome conflicts among various teachers' supervision, we propose Merge-of-Thought Distillation (MoT), a lightweight framework that alternates between teacher-specific supervised fine-tuning branches and weight-space merging of the resulting student variants. On competition math benchmarks, using only about 200 CoT samples, applying MoT to a Qwen3-14B student surpasses strong models including Deepseek-R1, Qwen3-32B, and OpenAI-O1, demonstrating substantial gains. Besides, MoT consistently outperforms the best single-teacher distillation, improves general reasoning beyond mathematics while reducing catastrophic forgetting, and shows robustness to distribution-shifted and peer-level teachers. Finally, we have demonstrated MoT possesses consensus CoT by eliminating teacher-specific inductive biases and inter-teacher conflicts while repeatedly reinforcing the learning of consensus reasoning features. These results position MoT as a simple, effective route to efficiently distilling long CoT capabilities from diverse teachers into compact students.
format Preprint
id arxiv_https___arxiv_org_abs_2509_08814
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Merge-of-Thought Distillation
Shen, Zhanming
Qin, Zeyu
Huang, Zenan
Chen, Hao
Hu, Jiaqi
Zhuang, Yihong
Lu, Guoshan
Chen, Gang
Zhao, Junbo
Machine Learning
Artificial Intelligence
Computation and Language
Efficient reasoning distillation for long chain-of-thought (CoT) models is increasingly constrained by the assumption of a single oracle teacher, despite the practical availability of multiple candidate teachers and growing CoT corpora. We revisit teacher selection and observe that different students have different "best teachers," and even for the same student, the best teacher can vary across datasets. Therefore, to unify multiple teachers' reasoning abilities into a student to overcome conflicts among various teachers' supervision, we propose Merge-of-Thought Distillation (MoT), a lightweight framework that alternates between teacher-specific supervised fine-tuning branches and weight-space merging of the resulting student variants. On competition math benchmarks, using only about 200 CoT samples, applying MoT to a Qwen3-14B student surpasses strong models including Deepseek-R1, Qwen3-32B, and OpenAI-O1, demonstrating substantial gains. Besides, MoT consistently outperforms the best single-teacher distillation, improves general reasoning beyond mathematics while reducing catastrophic forgetting, and shows robustness to distribution-shifted and peer-level teachers. Finally, we have demonstrated MoT possesses consensus CoT by eliminating teacher-specific inductive biases and inter-teacher conflicts while repeatedly reinforcing the learning of consensus reasoning features. These results position MoT as a simple, effective route to efficiently distilling long CoT capabilities from diverse teachers into compact students.
title Merge-of-Thought Distillation
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2509.08814