Incentivizing Strong Reasoning from Weak Supervision

Published: 15 Nov 2025, Last Modified: 08 Mar 2026AAAI 2026 Bridge LMReasoningEveryoneRevisionsBibTeXCC BY 4.0
Keywords: Large Language Model, Reasoning
TL;DR: We study the problem of incentivizing reasoning of LLMs from weak supervision, and find that weak reasoner teachers—4.7× smaller and 31.5% less performant than the student—can boost student reasoning by 56.25% without expert supervision or costly RL.
Abstract: Large language models (LLMs) have demonstrated impressive performance on reasoning-intensive tasks, but enhancing their reasoning abilities typically relies on either reinforcement learning (RL) with verifiable signals or supervised fine-tuning (SFT) with high-quality long chain-of-thought (CoT) demonstrations, both of which are expensive. In this paper, we study a novel problem of incentivizing the reasoning capacity of LLMs without expensive high-quality demonstrations and reinforcement learning. We investigate whether the reasoning capabilities of LLMs can be effectively incentivized via supervision from significantly weaker models. We further analyze when and why such weak supervision succeeds in eliciting reasoning abilities in stronger models. Our findings show that supervision from significantly weaker reasoners can substantially improve student reasoning performance, recovering close to 94\% of the gains of expensive RL at a fraction of the cost. Experiments across diverse benchmarks and model architectures demonstrate that weak reasoners can effectively incentivize reasoning in stronger student models, consistently improving performance across a wide range of reasoning tasks. Our results suggest that this simple weak-to-strong paradigm is a promising and generalizable alternative to costly methods for incentivizing strong reasoning capabilities at inference-time in LLMs. Code is at https://github.com/W2SR-AAAI/Code.
Submission Number: 30
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