VRM: Teaching Reward Models to Understand Authentic Human Preferences

Fuente: arXiv
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Hauptverfasser: Liu, Biao, Xu, Ning, Yang, Junming, Xu, Hao, Geng, Xin
Format: Preprint
Veröffentlicht: 2026
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author Liu, Biao
Xu, Ning
Yang, Junming
Xu, Hao
Geng, Xin
author_facet Liu, Biao
Xu, Ning
Yang, Junming
Xu, Hao
Geng, Xin
contents Large Language Models (LLMs) have achieved remarkable success across diverse natural language tasks, yet the reward models employed for aligning LLMs often encounter challenges of reward hacking, where the approaches predominantly rely on directly mapping prompt-response pairs to scalar scores, which may inadvertently capture spurious correlations rather than authentic human preferences. In contrast, human evaluation employs a sophisticated process that initially weighs the relative importance of multiple high-dimensional objectives according to the prompt context, subsequently evaluating response quality through low-dimensional semantic features such as logical coherence and contextual appropriateness. Motivated by this consideration, we propose VRM, i.e., Variational Reward Modeling, a novel framework that explicitly models the evaluation process of human preference judgments by incorporating both high-dimensional objective weights and low-dimensional semantic features as latent variables, which are inferred through variational inference techniques. Additionally, we provide a theoretical analysis showing that VRM can achieve a tighter generalization error bound compared to the traditional reward model. Extensive experiments on benchmark datasets demonstrate that VRM significantly outperforms existing methods in capturing authentic human preferences.
format Preprint
id arxiv_https___arxiv_org_abs_2603_04974
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle VRM: Teaching Reward Models to Understand Authentic Human Preferences
Liu, Biao
Xu, Ning
Yang, Junming
Xu, Hao
Geng, Xin
Computation and Language
Large Language Models (LLMs) have achieved remarkable success across diverse natural language tasks, yet the reward models employed for aligning LLMs often encounter challenges of reward hacking, where the approaches predominantly rely on directly mapping prompt-response pairs to scalar scores, which may inadvertently capture spurious correlations rather than authentic human preferences. In contrast, human evaluation employs a sophisticated process that initially weighs the relative importance of multiple high-dimensional objectives according to the prompt context, subsequently evaluating response quality through low-dimensional semantic features such as logical coherence and contextual appropriateness. Motivated by this consideration, we propose VRM, i.e., Variational Reward Modeling, a novel framework that explicitly models the evaluation process of human preference judgments by incorporating both high-dimensional objective weights and low-dimensional semantic features as latent variables, which are inferred through variational inference techniques. Additionally, we provide a theoretical analysis showing that VRM can achieve a tighter generalization error bound compared to the traditional reward model. Extensive experiments on benchmark datasets demonstrate that VRM significantly outperforms existing methods in capturing authentic human preferences.
title VRM: Teaching Reward Models to Understand Authentic Human Preferences
topic Computation and Language
url https://arxiv.org/abs/2603.04974