RLHF Fine-Tuning of LLMs for Alignment with Implicit User Feedback in Conversational Recommenders

Fuente: arXiv
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Autori principali: Yang, Zhongheng, Sun, Aijia, Zhao, Yushang, Yang, Yinuo, Li, Dannier, Zhou, Chengrui
Natura: Preprint
Pubblicazione: 2025
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author Yang, Zhongheng
Sun, Aijia
Zhao, Yushang
Yang, Yinuo
Li, Dannier
Zhou, Chengrui
author_facet Yang, Zhongheng
Sun, Aijia
Zhao, Yushang
Yang, Yinuo
Li, Dannier
Zhou, Chengrui
contents Conversational recommender systems (CRS) based on Large Language Models (LLMs) need to constantly be aligned to the user preferences to provide satisfying and context-relevant item recommendations. The traditional supervised fine-tuning cannot capture the implicit feedback signal, e.g., dwell time, sentiment polarity, or engagement patterns. In this paper, we share a fine-tuning solution using human feedback reinforcement learning (RLHF) to maximize implied user feedback (IUF) in a multi-turn recommendation context. We specify a reward model $R_ϕ$ learnt on weakly-labelled engagement information and maximize user-centric utility by optimizing the foundational LLM M_θ through a proximal policy optimization (PPO) approach. The architecture models conversational state transitions $s_t \to a_t \to s_{t +1}$, where the action $a_t$ is associated with LLM-generated item suggestions only on condition of conversation history in the past. The evaluation across synthetic and real-world datasets (e.g.REDIAL, OpenDialKG) demonstrates that our RLHF-fine-tuned models can perform better in terms of top-$k$ recommendation accuracy, coherence, and user satisfaction compared to (arrow-zero-cmwrquca-teja-falset ensuite 2Round group-deca States penalty give up This paper shows that implicit signal alignment can be efficient in achieving scalable and user-adaptive design of CRS.
format Preprint
id arxiv_https___arxiv_org_abs_2508_05289
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle RLHF Fine-Tuning of LLMs for Alignment with Implicit User Feedback in Conversational Recommenders
Yang, Zhongheng
Sun, Aijia
Zhao, Yushang
Yang, Yinuo
Li, Dannier
Zhou, Chengrui
Machine Learning
Conversational recommender systems (CRS) based on Large Language Models (LLMs) need to constantly be aligned to the user preferences to provide satisfying and context-relevant item recommendations. The traditional supervised fine-tuning cannot capture the implicit feedback signal, e.g., dwell time, sentiment polarity, or engagement patterns. In this paper, we share a fine-tuning solution using human feedback reinforcement learning (RLHF) to maximize implied user feedback (IUF) in a multi-turn recommendation context. We specify a reward model $R_ϕ$ learnt on weakly-labelled engagement information and maximize user-centric utility by optimizing the foundational LLM M_θ through a proximal policy optimization (PPO) approach. The architecture models conversational state transitions $s_t \to a_t \to s_{t +1}$, where the action $a_t$ is associated with LLM-generated item suggestions only on condition of conversation history in the past. The evaluation across synthetic and real-world datasets (e.g.REDIAL, OpenDialKG) demonstrates that our RLHF-fine-tuned models can perform better in terms of top-$k$ recommendation accuracy, coherence, and user satisfaction compared to (arrow-zero-cmwrquca-teja-falset ensuite 2Round group-deca States penalty give up This paper shows that implicit signal alignment can be efficient in achieving scalable and user-adaptive design of CRS.
title RLHF Fine-Tuning of LLMs for Alignment with Implicit User Feedback in Conversational Recommenders
topic Machine Learning
url https://arxiv.org/abs/2508.05289