Hybrid Latent Reasoning via Reinforcement Learning

Fuente: arXiv
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Main Authors: Yue, Zhenrui, Jin, Bowen, Zeng, Huimin, Zhuang, Honglei, Qin, Zhen, Yoon, Jinsung, Shang, Lanyu, Han, Jiawei, Wang, Dong
Format: Preprint
Published: 2025
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author Yue, Zhenrui
Jin, Bowen
Zeng, Huimin
Zhuang, Honglei
Qin, Zhen
Yoon, Jinsung
Shang, Lanyu
Han, Jiawei
Wang, Dong
author_facet Yue, Zhenrui
Jin, Bowen
Zeng, Huimin
Zhuang, Honglei
Qin, Zhen
Yoon, Jinsung
Shang, Lanyu
Han, Jiawei
Wang, Dong
contents Recent advances in large language models (LLMs) have introduced latent reasoning as a promising alternative to autoregressive reasoning. By performing internal computation with hidden states from previous steps, latent reasoning benefit from more informative features rather than sampling a discrete chain-of-thought (CoT) path. Yet latent reasoning approaches are often incompatible with LLMs, as their continuous paradigm conflicts with the discrete nature of autoregressive generation. Moreover, these methods rely on CoT traces for training and thus fail to exploit the inherent reasoning patterns of LLMs. In this work, we explore latent reasoning by leveraging the intrinsic capabilities of LLMs via reinforcement learning (RL). To this end, we introduce hybrid reasoning policy optimization (HRPO), an RL-based hybrid latent reasoning approach that (1) integrates prior hidden states into sampled tokens with a learnable gating mechanism, and (2) initializes training with predominantly token embeddings while progressively incorporating more hidden features. This design maintains LLMs' generative capabilities and incentivizes hybrid reasoning using both discrete and continuous representations. In addition, the hybrid HRPO introduces stochasticity into latent reasoning via token sampling, thereby enabling RL-based optimization without requiring CoT trajectories. Extensive evaluations across diverse benchmarks show that HRPO outperforms prior methods in both knowledge- and reasoning-intensive tasks. Furthermore, HRPO-trained LLMs remain interpretable and exhibit intriguing behaviors like cross-lingual patterns and shorter completion lengths, highlighting the potential of our RL-based approach and offer insights for future work in latent reasoning.
format Preprint
id arxiv_https___arxiv_org_abs_2505_18454
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Hybrid Latent Reasoning via Reinforcement Learning
Yue, Zhenrui
Jin, Bowen
Zeng, Huimin
Zhuang, Honglei
Qin, Zhen
Yoon, Jinsung
Shang, Lanyu
Han, Jiawei
Wang, Dong
Computation and Language
Recent advances in large language models (LLMs) have introduced latent reasoning as a promising alternative to autoregressive reasoning. By performing internal computation with hidden states from previous steps, latent reasoning benefit from more informative features rather than sampling a discrete chain-of-thought (CoT) path. Yet latent reasoning approaches are often incompatible with LLMs, as their continuous paradigm conflicts with the discrete nature of autoregressive generation. Moreover, these methods rely on CoT traces for training and thus fail to exploit the inherent reasoning patterns of LLMs. In this work, we explore latent reasoning by leveraging the intrinsic capabilities of LLMs via reinforcement learning (RL). To this end, we introduce hybrid reasoning policy optimization (HRPO), an RL-based hybrid latent reasoning approach that (1) integrates prior hidden states into sampled tokens with a learnable gating mechanism, and (2) initializes training with predominantly token embeddings while progressively incorporating more hidden features. This design maintains LLMs' generative capabilities and incentivizes hybrid reasoning using both discrete and continuous representations. In addition, the hybrid HRPO introduces stochasticity into latent reasoning via token sampling, thereby enabling RL-based optimization without requiring CoT trajectories. Extensive evaluations across diverse benchmarks show that HRPO outperforms prior methods in both knowledge- and reasoning-intensive tasks. Furthermore, HRPO-trained LLMs remain interpretable and exhibit intriguing behaviors like cross-lingual patterns and shorter completion lengths, highlighting the potential of our RL-based approach and offer insights for future work in latent reasoning.
title Hybrid Latent Reasoning via Reinforcement Learning
topic Computation and Language
url https://arxiv.org/abs/2505.18454