SEM: Reinforcement Learning for Search-Efficient Large Language Models

Fuente: arXiv
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Hauptverfasser: Sha, Zeyang, Cui, Shiwen, Wang, Weiqiang
Format: Preprint
Veröffentlicht: 2025
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author Sha, Zeyang
Cui, Shiwen
Wang, Weiqiang
author_facet Sha, Zeyang
Cui, Shiwen
Wang, Weiqiang
contents Recent advancements in Large Language Models(LLMs) have demonstrated their capabilities not only in reasoning but also in invoking external tools, particularly search engines. However, teaching models to discern when to invoke search and when to rely on their internal knowledge remains a significant challenge. Existing reinforcement learning approaches often lead to redundant search behaviors, resulting in inefficiencies and over-cost. In this paper, we propose SEM, a novel post-training reinforcement learning framework that explicitly trains LLMs to optimize search usage. By constructing a balanced dataset combining MuSiQue and MMLU, we create scenarios where the model must learn to distinguish between questions it can answer directly and those requiring external retrieval. We design a structured reasoning template and employ Group Relative Policy Optimization(GRPO) to post-train the model's search behaviors. Our reward function encourages accurate answering without unnecessary search while promoting effective retrieval when needed. Experimental results demonstrate that our method significantly reduces redundant search operations while maintaining or improving answer accuracy across multiple challenging benchmarks. This framework advances the model's reasoning efficiency and extends its capability to judiciously leverage external knowledge.
format Preprint
id arxiv_https___arxiv_org_abs_2505_07903
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle SEM: Reinforcement Learning for Search-Efficient Large Language Models
Sha, Zeyang
Cui, Shiwen
Wang, Weiqiang
Computation and Language
Artificial Intelligence
Recent advancements in Large Language Models(LLMs) have demonstrated their capabilities not only in reasoning but also in invoking external tools, particularly search engines. However, teaching models to discern when to invoke search and when to rely on their internal knowledge remains a significant challenge. Existing reinforcement learning approaches often lead to redundant search behaviors, resulting in inefficiencies and over-cost. In this paper, we propose SEM, a novel post-training reinforcement learning framework that explicitly trains LLMs to optimize search usage. By constructing a balanced dataset combining MuSiQue and MMLU, we create scenarios where the model must learn to distinguish between questions it can answer directly and those requiring external retrieval. We design a structured reasoning template and employ Group Relative Policy Optimization(GRPO) to post-train the model's search behaviors. Our reward function encourages accurate answering without unnecessary search while promoting effective retrieval when needed. Experimental results demonstrate that our method significantly reduces redundant search operations while maintaining or improving answer accuracy across multiple challenging benchmarks. This framework advances the model's reasoning efficiency and extends its capability to judiciously leverage external knowledge.
title SEM: Reinforcement Learning for Search-Efficient Large Language Models
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2505.07903