Improving Reinforcement Learning from Human Feedback Using Contrastive Rewards

Fuente: arXiv
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Hauptverfasser: Shen, Wei, Zhang, Xiaoying, Yao, Yuanshun, Zheng, Rui, Guo, Hongyi, Liu, Yang
Format: Preprint
Veröffentlicht: 2024
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author Shen, Wei
Zhang, Xiaoying
Yao, Yuanshun
Zheng, Rui
Guo, Hongyi
Liu, Yang
author_facet Shen, Wei
Zhang, Xiaoying
Yao, Yuanshun
Zheng, Rui
Guo, Hongyi
Liu, Yang
contents Reinforcement learning from human feedback (RLHF) is the mainstream paradigm used to align large language models (LLMs) with human preferences. Yet existing RLHF heavily relies on accurate and informative reward models, which are vulnerable and sensitive to noise from various sources, e.g. human labeling errors, making the pipeline fragile. In this work, we improve the effectiveness of the reward model by introducing a penalty term on the reward, named as \textit{contrastive rewards}. %Contrastive rewards Our approach involves two steps: (1) an offline sampling step to obtain responses to prompts that serve as baseline calculation and (2) a contrastive reward calculated using the baseline responses and used in the Proximal Policy Optimization (PPO) step. We show that contrastive rewards enable the LLM to penalize reward uncertainty, improve robustness, encourage improvement over baselines, calibrate according to task difficulty, and reduce variance in PPO. We show empirically contrastive rewards can improve RLHF substantially, evaluated by both GPTs and humans, and our method consistently outperforms strong baselines.
format Preprint
id arxiv_https___arxiv_org_abs_2403_07708
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Improving Reinforcement Learning from Human Feedback Using Contrastive Rewards
Shen, Wei
Zhang, Xiaoying
Yao, Yuanshun
Zheng, Rui
Guo, Hongyi
Liu, Yang
Computation and Language
Artificial Intelligence
Reinforcement learning from human feedback (RLHF) is the mainstream paradigm used to align large language models (LLMs) with human preferences. Yet existing RLHF heavily relies on accurate and informative reward models, which are vulnerable and sensitive to noise from various sources, e.g. human labeling errors, making the pipeline fragile. In this work, we improve the effectiveness of the reward model by introducing a penalty term on the reward, named as \textit{contrastive rewards}. %Contrastive rewards Our approach involves two steps: (1) an offline sampling step to obtain responses to prompts that serve as baseline calculation and (2) a contrastive reward calculated using the baseline responses and used in the Proximal Policy Optimization (PPO) step. We show that contrastive rewards enable the LLM to penalize reward uncertainty, improve robustness, encourage improvement over baselines, calibrate according to task difficulty, and reduce variance in PPO. We show empirically contrastive rewards can improve RLHF substantially, evaluated by both GPTs and humans, and our method consistently outperforms strong baselines.
title Improving Reinforcement Learning from Human Feedback Using Contrastive Rewards
topic Computation and Language
Artificial Intelligence
url https://arxiv.org/abs/2403.07708