Language Model Personalization via Reward Factorization

Fuente: arXiv
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Main Authors: Shenfeld, Idan, Faltings, Felix, Agrawal, Pulkit, Pacchiano, Aldo
Format: Preprint
Published: 2025
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author Shenfeld, Idan
Faltings, Felix
Agrawal, Pulkit
Pacchiano, Aldo
author_facet Shenfeld, Idan
Faltings, Felix
Agrawal, Pulkit
Pacchiano, Aldo
contents Modern large language models (LLMs) are optimized for human-aligned responses using Reinforcement Learning from Human Feedback (RLHF). However, existing RLHF approaches assume a universal preference model and fail to account for individual user preferences, limiting their effectiveness in personalized applications. We introduce a framework that extends RLHF to enable user personalization by leveraging the assumption that user preferences lie in a low-dimensional space. Instead of training a separate model per user, we represent user-specific rewards as a linear combination of base reward functions. Using only ~10 user responses, our method can infer user-specific rewards and align LLM outputs accordingly. We validate our approach through experiments with both synthetic and real users, demonstrating significant personalization achieved by our method. In human evaluations, our method achieves a 67% win rate over default GPT-4o responses.
format Preprint
id arxiv_https___arxiv_org_abs_2503_06358
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Language Model Personalization via Reward Factorization
Shenfeld, Idan
Faltings, Felix
Agrawal, Pulkit
Pacchiano, Aldo
Machine Learning
Modern large language models (LLMs) are optimized for human-aligned responses using Reinforcement Learning from Human Feedback (RLHF). However, existing RLHF approaches assume a universal preference model and fail to account for individual user preferences, limiting their effectiveness in personalized applications. We introduce a framework that extends RLHF to enable user personalization by leveraging the assumption that user preferences lie in a low-dimensional space. Instead of training a separate model per user, we represent user-specific rewards as a linear combination of base reward functions. Using only ~10 user responses, our method can infer user-specific rewards and align LLM outputs accordingly. We validate our approach through experiments with both synthetic and real users, demonstrating significant personalization achieved by our method. In human evaluations, our method achieves a 67% win rate over default GPT-4o responses.
title Language Model Personalization via Reward Factorization
topic Machine Learning
url https://arxiv.org/abs/2503.06358