MA-RLHF: Reinforcement Learning from Human Feedback with Macro Actions

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Main Authors: Chai, Yekun, Sun, Haoran, Fang, Huang, Wang, Shuohuan, Sun, Yu, Wu, Hua
Format: Preprint
Published: 2024
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author Chai, Yekun
Sun, Haoran
Fang, Huang
Wang, Shuohuan
Sun, Yu
Wu, Hua
author_facet Chai, Yekun
Sun, Haoran
Fang, Huang
Wang, Shuohuan
Sun, Yu
Wu, Hua
contents Reinforcement learning from human feedback (RLHF) has demonstrated effectiveness in aligning large language models (LLMs) with human preferences. However, token-level RLHF suffers from the credit assignment problem over long sequences, where delayed rewards make it challenging for the model to discern which actions contributed to preferred outcomes. This hinders learning efficiency and slows convergence.In this paper, we propose MA-RLHF, a simple yet effective RLHF framework that incorporates macro actions -- sequences of tokens or higher-level language constructs -- into the learning process. By operating at higher level of abstraction, our approach reduces the temporal distance between actions and rewards, facilitating faster and more accurate credit assignment. This results in more stable policy gradient estimates and enhances learning efficiency within each episode, all without increasing computational complexity during training or inference. We validate our approach through extensive experiments across various model sizes and tasks, including text summarization, dialogue generation, question answering, and program synthesis. Our method achieves substantial performance improvements over standard RLHF, with performance gains of up to 30% in text summarization and code generation, 18% in dialogue, and 8% in question answering tasks. Notably, our approach reaches parity with vanilla RLHF 1.7 ~ 2 times faster in terms of training time and continues to outperform it with further training. We make our code and data publicly available at https://github.com/ernie-research/MA-RLHF.
format Preprint
id arxiv_https___arxiv_org_abs_2410_02743
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle MA-RLHF: Reinforcement Learning from Human Feedback with Macro Actions
Chai, Yekun
Sun, Haoran
Fang, Huang
Wang, Shuohuan
Sun, Yu
Wu, Hua
Computation and Language
Reinforcement learning from human feedback (RLHF) has demonstrated effectiveness in aligning large language models (LLMs) with human preferences. However, token-level RLHF suffers from the credit assignment problem over long sequences, where delayed rewards make it challenging for the model to discern which actions contributed to preferred outcomes. This hinders learning efficiency and slows convergence.In this paper, we propose MA-RLHF, a simple yet effective RLHF framework that incorporates macro actions -- sequences of tokens or higher-level language constructs -- into the learning process. By operating at higher level of abstraction, our approach reduces the temporal distance between actions and rewards, facilitating faster and more accurate credit assignment. This results in more stable policy gradient estimates and enhances learning efficiency within each episode, all without increasing computational complexity during training or inference. We validate our approach through extensive experiments across various model sizes and tasks, including text summarization, dialogue generation, question answering, and program synthesis. Our method achieves substantial performance improvements over standard RLHF, with performance gains of up to 30% in text summarization and code generation, 18% in dialogue, and 8% in question answering tasks. Notably, our approach reaches parity with vanilla RLHF 1.7 ~ 2 times faster in terms of training time and continues to outperform it with further training. We make our code and data publicly available at https://github.com/ernie-research/MA-RLHF.
title MA-RLHF: Reinforcement Learning from Human Feedback with Macro Actions
topic Computation and Language
url https://arxiv.org/abs/2410.02743