Implicit Reasoning in Large Language Models: A Comprehensive Survey

Fuente: arXiv
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Main Authors: Li, Jindong, Fu, Yali, Fan, Li, Liu, Jiahong, Shu, Yao, Qin, Chengwei, Yang, Menglin, King, Irwin, Ying, Rex
Format: Preprint
Published: 2025
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author Li, Jindong
Fu, Yali
Fan, Li
Liu, Jiahong
Shu, Yao
Qin, Chengwei
Yang, Menglin
King, Irwin
Ying, Rex
author_facet Li, Jindong
Fu, Yali
Fan, Li
Liu, Jiahong
Shu, Yao
Qin, Chengwei
Yang, Menglin
King, Irwin
Ying, Rex
contents Large Language Models (LLMs) have demonstrated strong generalization across a wide range of tasks. Reasoning with LLMs is central to solving multi-step problems and complex decision-making. To support efficient reasoning, recent studies have shifted attention from explicit chain-of-thought prompting toward implicit reasoning, where reasoning occurs silently via latent structures without emitting intermediate textual steps. Implicit reasoning brings advantages such as lower generation cost, faster inference, and better alignment with internal computation. Although prior surveys have discussed latent representations in the context of reasoning, a dedicated and mechanism-level examination of how reasoning unfolds internally within LLMs remains absent. This survey fills that gap by introducing a taxonomy centered on execution paradigms, shifting the focus from representational forms to computational strategies. We organize existing methods into three execution paradigms based on \textbf{\textit{how and where internal computation unfolds}}: latent optimization, signal-guided control, and layer-recurrent execution. We also review structural, behavioral and representation-based evidence that supports the presence of implicit reasoning in LLMs. We further provide a structured overview of the evaluation metrics and benchmarks used in existing works to assess the effectiveness and reliability of implicit reasoning. We maintain a continuously updated project at: https://github.com/digailab/awesome-llm-implicit-reasoning.
format Preprint
id arxiv_https___arxiv_org_abs_2509_02350
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Implicit Reasoning in Large Language Models: A Comprehensive Survey
Li, Jindong
Fu, Yali
Fan, Li
Liu, Jiahong
Shu, Yao
Qin, Chengwei
Yang, Menglin
King, Irwin
Ying, Rex
Computation and Language
Artificial Intelligence
Large Language Models (LLMs) have demonstrated strong generalization across a wide range of tasks. Reasoning with LLMs is central to solving multi-step problems and complex decision-making. To support efficient reasoning, recent studies have shifted attention from explicit chain-of-thought prompting toward implicit reasoning, where reasoning occurs silently via latent structures without emitting intermediate textual steps. Implicit reasoning brings advantages such as lower generation cost, faster inference, and better alignment with internal computation. Although prior surveys have discussed latent representations in the context of reasoning, a dedicated and mechanism-level examination of how reasoning unfolds internally within LLMs remains absent. This survey fills that gap by introducing a taxonomy centered on execution paradigms, shifting the focus from representational forms to computational strategies. We organize existing methods into three execution paradigms based on \textbf{\textit{how and where internal computation unfolds}}: latent optimization, signal-guided control, and layer-recurrent execution. We also review structural, behavioral and representation-based evidence that supports the presence of implicit reasoning in LLMs. We further provide a structured overview of the evaluation metrics and benchmarks used in existing works to assess the effectiveness and reliability of implicit reasoning. We maintain a continuously updated project at: https://github.com/digailab/awesome-llm-implicit-reasoning.
title Implicit Reasoning in Large Language Models: A Comprehensive Survey
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2509.02350