Reinforcement Learning from Human Feedback with High-Confidence Safety Constraints

Fuente: arXiv
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Autori principali: Chittepu, Yaswanth, Metevier, Blossom, Schwarzer, Will, Hoag, Austin, Niekum, Scott, Thomas, Philip S.
Natura: Preprint
Pubblicazione: 2025
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author Chittepu, Yaswanth
Metevier, Blossom
Schwarzer, Will
Hoag, Austin
Niekum, Scott
Thomas, Philip S.
author_facet Chittepu, Yaswanth
Metevier, Blossom
Schwarzer, Will
Hoag, Austin
Niekum, Scott
Thomas, Philip S.
contents Existing approaches to language model alignment often treat safety as a tradeoff against helpfulness, which can lead to unacceptable responses in sensitive domains. To ensure reliable performance in such settings, we propose High-Confidence Safe Reinforcement Learning from Human Feedback (HC-RLHF), a method that provides high-confidence safety guarantees while maximizing helpfulness. Similar to previous methods, HC-RLHF explicitly decouples human preferences into helpfulness and harmlessness (safety), which are learned by training a reward model and a cost model, respectively. It then employs a two-step process to find safe solutions. In the first step, it optimizes the reward function under an intentionally pessimistic version of the cost constraint. In the second step, the trained model undergoes a safety test to verify whether its performance stays within an upper-confidence bound of the actual cost constraint. We provide a theoretical analysis of HC-RLHF, including proof that it will not return an unsafe solution with a probability greater than a user-specified threshold. For our empirical analysis, we apply HC-RLHF to align three different language models (Qwen2-1.5B, Qwen2.5-3B, and LLaMa3.2-3B) with human preferences. Our results demonstrate that HC-RLHF produces safe models with high probability and can improve harmlessness and helpfulness compared to previous methods.
format Preprint
id arxiv_https___arxiv_org_abs_2506_08266
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Reinforcement Learning from Human Feedback with High-Confidence Safety Constraints
Chittepu, Yaswanth
Metevier, Blossom
Schwarzer, Will
Hoag, Austin
Niekum, Scott
Thomas, Philip S.
Machine Learning
Artificial Intelligence
Computation and Language
Applications
Existing approaches to language model alignment often treat safety as a tradeoff against helpfulness, which can lead to unacceptable responses in sensitive domains. To ensure reliable performance in such settings, we propose High-Confidence Safe Reinforcement Learning from Human Feedback (HC-RLHF), a method that provides high-confidence safety guarantees while maximizing helpfulness. Similar to previous methods, HC-RLHF explicitly decouples human preferences into helpfulness and harmlessness (safety), which are learned by training a reward model and a cost model, respectively. It then employs a two-step process to find safe solutions. In the first step, it optimizes the reward function under an intentionally pessimistic version of the cost constraint. In the second step, the trained model undergoes a safety test to verify whether its performance stays within an upper-confidence bound of the actual cost constraint. We provide a theoretical analysis of HC-RLHF, including proof that it will not return an unsafe solution with a probability greater than a user-specified threshold. For our empirical analysis, we apply HC-RLHF to align three different language models (Qwen2-1.5B, Qwen2.5-3B, and LLaMa3.2-3B) with human preferences. Our results demonstrate that HC-RLHF produces safe models with high probability and can improve harmlessness and helpfulness compared to previous methods.
title Reinforcement Learning from Human Feedback with High-Confidence Safety Constraints
topic Machine Learning
Artificial Intelligence
Computation and Language
Applications
url https://arxiv.org/abs/2506.08266