Your Language Model is Its Own Critic: Reinforcement Learning with Value Estimation from Actor's Internal States

Fuente: arXiv
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Main Authors: Choi, Yunho, Lim, Jongwon, Ahn, Woojin, Oh, Minjae, Shim, Jeonghoon, Jo, Yohan
Format: Preprint
Published: 2026
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author Choi, Yunho
Lim, Jongwon
Ahn, Woojin
Oh, Minjae
Shim, Jeonghoon
Jo, Yohan
author_facet Choi, Yunho
Lim, Jongwon
Ahn, Woojin
Oh, Minjae
Shim, Jeonghoon
Jo, Yohan
contents Reinforcement learning with verifiable rewards (RLVR) for Large Reasoning Models hinges on baseline estimation for variance reduction, but existing approaches pay a heavy price: PPO requires a policy-model scale critic, while GRPO needs multiple rollouts per prompt to keep its empirical group mean stable. We introduce Policy Optimization with Internal State Value Estimation), which obtains a baseline at negligible cost by using the policy model's internal signals already computed during the policy forward pass. A lightweight probe predicts the expected verifiable reward from the hidden states of the prompt and generated trajectory, as well as token-entropy statistics, and is trained online alongside the policy. To preserve gradient unbiasedness despite using trajectory-conditioned features, we introduce a cross-rollout construction that predicts each rollout's value from an independent rollout's internal states. Because POISE estimates prompt value using only a single rollout, it enables higher prompt diversity for a fixed compute budget during training. This reduces gradient variance for more stable learning and also eliminates the compute overhead of sampling costs for detecting zero-advantage prompts. On Qwen3-4B and DeepSeek-R1-Distill-Qwen-1.5B across math reasoning benchmarks, POISE matches DAPO while requiring less compute. Moreover, its value estimator shows similar performance to a separate LLM-scale value model and generalizes to various verifiable tasks. By leveraging the model's own internal representations, POISE enables more stable and efficient policy optimization.
format Preprint
id arxiv_https___arxiv_org_abs_2605_07579
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Your Language Model is Its Own Critic: Reinforcement Learning with Value Estimation from Actor's Internal States
Choi, Yunho
Lim, Jongwon
Ahn, Woojin
Oh, Minjae
Shim, Jeonghoon
Jo, Yohan
Machine Learning
Artificial Intelligence
Computation and Language
Reinforcement learning with verifiable rewards (RLVR) for Large Reasoning Models hinges on baseline estimation for variance reduction, but existing approaches pay a heavy price: PPO requires a policy-model scale critic, while GRPO needs multiple rollouts per prompt to keep its empirical group mean stable. We introduce Policy Optimization with Internal State Value Estimation), which obtains a baseline at negligible cost by using the policy model's internal signals already computed during the policy forward pass. A lightweight probe predicts the expected verifiable reward from the hidden states of the prompt and generated trajectory, as well as token-entropy statistics, and is trained online alongside the policy. To preserve gradient unbiasedness despite using trajectory-conditioned features, we introduce a cross-rollout construction that predicts each rollout's value from an independent rollout's internal states. Because POISE estimates prompt value using only a single rollout, it enables higher prompt diversity for a fixed compute budget during training. This reduces gradient variance for more stable learning and also eliminates the compute overhead of sampling costs for detecting zero-advantage prompts. On Qwen3-4B and DeepSeek-R1-Distill-Qwen-1.5B across math reasoning benchmarks, POISE matches DAPO while requiring less compute. Moreover, its value estimator shows similar performance to a separate LLM-scale value model and generalizes to various verifiable tasks. By leveraging the model's own internal representations, POISE enables more stable and efficient policy optimization.
title Your Language Model is Its Own Critic: Reinforcement Learning with Value Estimation from Actor's Internal States
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2605.07579